date:20160608



% $250 reservation, EV's appearance has changed slightly away from a Sparrow
EV, may not be able to install a rear baby seat but has room for a few bags
of groceries, j1772 port L2-3kW &L1 charging, colors: silver, red, or black
(r:100mi ts:75mph 0-60mph:8s) %

http://www.treehugger.com/cars/solo-single-passenger-electric-three-wheeler-slated-july-launch.html#14649891688571&action=collapse_widget&id=0&data=
The SOLO, a single passenger electric three-wheeler, is slated for July
launch
June 3, 2016  Derek Markham

[images  / Electra Meccanica
http://media.treehugger.com/assets/images/2016/06/SOLO-white.jpg.662x0_q70_crop-scale.jpg
Electra Meccanica SOLO

http://media.treehugger.com/assets/images/2016/06/SOLO-red.jpg.650x0_q70_crop-smart.jpg
]

Looking for a smaller, less costly EV as a supplemental vehicle? The Electra
Meccanica SOLO could be well worth considering.

Vancouver-based Electra Meccanica is taking aim at the small EV market with
its forthcoming SOLO, a three-wheeled single passenger all-electric vehicle,
which is expected to go into full production in July of 2016. This little
electric vehicle isn't intended to replace the family car, as it doesn't
have the large carrying capacity or long range of a gas car, but is instead
expected to be an economical and zero (tailpipe) emissions vehicle that
could be a green and clean commuter option.

The folks behind the SOLO aren't new to the auto industry, as one of the
founders, Henry Reisner, has been building custom vehicles since the 1950s
under the Intermeccanica banner, and the other, Jerry Kroll, has run a high
tech electric racing vehicle development company (as well as being a veteran
race car driver), but this new entry into the EV market is quite different
from the focus of the full-sized electric car industry. It's small, it's
light, and it promises to be both fast and affordable. In an interview last
year, Kroll referred to the car as "the Volkswagen Beetle for the 21st
century," and likened driving it to "wearing Robert Downey Jr.’s Ironman
suit."

"Approximately 90% of travel is done single passenger. Why should you have
to pay for the gas and expense of transporting a 3,000+lb vehicle with only
one person in the car? SOLO is designed to get you to and from work and
around town as needed at minimal expense." - Electra Meccanica

The SOLO is expected to retail for about $19,888 CAD (~ $15,359 USD), which,
while not exactly cheap, is significantly less than many other full-electric
models (although it also has a significantly smaller hauling capacity as
well), and Electra Meccanica has already taken quite a few individual
refundable deposits for pre-orders of the initial model (in addition to the
claimed 20,500 commercial orders), which is expected to go into full
production this summer. With an estimated driving range of 125 miles between
charges, this little EV could meet a very real need, which is the single
passenger commuter vehicle (but would also be an excellent choice for a
courier or delivery vehicle).

According to the company's website, the SOLO will be 'fueled' by a 8.64 kW/h
lithium-ion battery, which will drive a rear electric motor that is said to
deliver up to 82hp and push the vehicle to a top speed of 120 kmh (~75mph),
with an acceleration capability of going from 0-100 kmh (0-62 mph) in about
8 seconds. The car weighs in at about 450 kg (992 lb) and looks to be small
enough to fit into parking spots that most vehicles (other than motorcycles)
could not fit into. It has only a single seat, but is said to be able to fit
"several bags of groceries" in its rear cargo area.

Although many people are somewhat skeptical of any vehicle with only 3
wheels, the SOLO is the result of decades of experience in designing and
building performance cars, and its creators are confident of its stability
on the road:

"Because our engineering team’s specialty is building world-class sports
cars, we focused on applying what we’ve learned over the last 50 years to
the Solo. The batteries are slung low along the frame of the car so as to
create an extremely low center of gravity, providing excellent handling." -
Henry Reisner, Chief Engineer

The SOLO is expected to take a full charge on its battery in about 3 hours
(on a 220V connection), so it seems like it would be possible to drive it
all the way to the full end of its range each day, as long as you've got
access to a charging outlet and a couple of hours before your return trip.
[© 2016 NARRATIVE CONTEN]
...
http://electrameccanica.com/about/
SOLO Technical Specifications
http://electrameccanica.com/wp-content/uploads/2016/04/Solo_Specs2-1.pdf
...
https://www.facebook.com/EMVsolo/
Electra Meccanica SOLO
https://twitter.com/electramecc
...
https://www.linkedin.com/company/electra-meccanica



http://electrek.co/2016/06/03/solo-electra-meccanica-all-electric-three-wheeler/
Electra Meccanica puts its all-electric single passenger commuter to the
test, production pushed to July
[2016/06/03]  F

[EVDL] EVLN: EV-newswire posts for 20160608



http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-26-more-public-EVSE-au-to-support-EV-industries-more-innovative-future-td4682448.html
EVLN: 26 more public EVSE.au to support EV industries' more innovative
future
Greens promise electric car charging stations
The Greens have released a policy to fund 26 charging stations in SA to
increase the uptake of electric cars ...

http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-Watt-determines-an-EV-battery-pack-s-price-td4682449.html
EVLN: Watt determines an EV battery pack's price?
Electric-car battery costs not too sensitive to lithium prices
 ... how much does the volatility of the price of lithium itself affect the
prices of those cells? ...

http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-CAD19-9k-USD15-4k-SOLO-3-wheel-1-seat-BC-ca-built-EV-r-160km-ts-120kph-td4682450.html
EVLN: CAD19.9k/USD15.4k SOLO 3-wheel 1-seat BC.ca-built EV r:160km ts:120kph
The SOLO, a single passenger electric three-wheeler, is slated for July ...
Why should you have to pay for the gas and expense of transporting a
3,000+lb vehicle with only one person in the car? SOLO is designed to ...

http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-Zoe-EV-spotted-in-Bangalore-in-with-UK-license-plates-td4682451.html
EVLN: Zoe EV spotted in Bangalore.in with UK license plates
Renault Zoe electric hatchback spotted in Bangalore
 ... is being sold in the affordable end of the European EV market has been
spotted in Bangalore with ...




http://evdl.org/evln/
For all EVLN EV-newswire posts


{brucedp.150m.com}

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[EVDL] Practical Non-Environmental Reasons to make a Massive Shift from ice to EVs

http://www.planetizen.com/node/86687/non-environmental-reasons-massive-switch-electric-cars
The Non-Environmental Reasons for a Massive Switch to Electric Cars
June 4, 2016 wadams92101

There are several practical reasons people will soon be switching to plugin
electrical vehicles. Judging from past examples, the shift in consumer
preference will be swift and decisive, catching car manufacturers by
surprise.

The everyday practical reasons to choose a plugin electric car over a gas
powered car are already here. However, consumer demand for them have been
underwhelming. Consumer awareness of electric vehicle advantages lags,
believes San Diego land use attorney Bill Adams, using his own learning
curve as an example. Much of the public is still under the impression that
owning an electric vehicle is an exercise in paying more and getting less to
save the climate. He predicts that consumer knowledge about the practical
non-environmental advantages of purchasing an electric car will soon result
in a swift and massive switch in consumer preference from gas to electric
vehicles. Practical benefits include:

1) Convenience: Forget about gas stations—fuel up at home at night. Quick
charging at charge stations for long trips is improving.

2) Fuel Cost: Charging up is cheaper than fueling up.

3) Reliability and maintenance cost: Fewer moving parts mean fewer repairs
and less maintenance.

4) Performance: Electric vehicles have superior torque and no transmission
gear change delays.

5) Tax credits and rebates: For new vehicle purchases, buyers get a $7,500
tax credit, and in California, a $2,500 rebate ($4,000 for people with
income up to 3 x poverty level).

6) Infrastructure: Charging stations are relatively easy and cheap to build
[install] compared to gas stations.

7) Inevitability: The global conversion is inevitable, which itself will
drive demand as consumers will not want to purchase new vehicles that will
become obsolete ...
[© 2016 Planetizen]
...
http://sandiego.urbdezine.com/2016/05/30/reasons-buy-electric-vehicle/
Reasons to buy an electric vehicle that have nothing to do with the
environment (and which portend an imminent and rapid global shift to
electric vehicles)
May 30, 2016

For EVLN EV-newswire posts use:
http://evdl.org/evln/

{brucedp.150m.com}

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View this message in context:
http://electric-vehicle-discussion-list.413529.n4.nabble.com/Practical-Non-Environmental-Reasons-to-make-a-Massive-Shift-from-ice-to-EVs-tp4682454.html
Sent from the Electric Vehicle Discussion List mailing list archive at
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[EVDL] Samsung wises up

2016-06-08 Thread EVDL Administrator via EV

http://www.greencarreports.com/news/1104333_samsung-says-sayonara-to-fuel-
cells-focuses-on-batteries-for-electric-cars

https://v.gd/i7emCJ

South Korea's Samsung SDI has decided to drop its hydrogen fuel-cell 
division, and focus future development resources exclusively on batteries 
for electric cars.

Samsung SDI is already a major player in the electric-car battery market.  
But until recently the company also dabbled in fuel-cell technology, largely 

the province of Japanese companies supplying Toyota and Honda.   But it is 
something executives are now no longer interested in continuing, according 
to a recent report by The Korea Times (via Charged EVs).

Samsung SDI decided to drop its fuel-cell projects because the "outlook of 
the market isn't good," according to a company spokesperson quoted in the 
report.  The same spokesperson said fuel-cell patents and equipment would be 

sold to a local company, but would not name the purchaser.  Kolon Industries 

subsequently acknowledged that it had been approached by Samsung SDI about a 

deal on the equipment and related assets.

Samsung's fuel-cell work dates back to 2005, when it developed small cells 
to power laptops.  However, advances in lithium-ion battery technology 
eventually rendered these fuel cells uncompetitive.

Samsung is in the midst of a larger process of cutting projects and product 
lines it believes to be unprofitable, and redirecting resources to only 
those it considers will remain core businesses.

The company now plans to invest more than 3 trillion won (about $2.5 
billion) in electric-car battery development over the next five years.  
Samsung hopes to become the world's top electric-car battery supplier by 
2020.  Along with LG Chem, Samsung is already set to supply cells for the 
all-electric Audi SUV due in 2018, and supplies cells for the BMW i3 and i8.

Samsung is also one of several companies reportedly in talks with Tesla 
Motors to supply battery cells for the automaker's Model 3 electric car.  
Tesla is already building a massive battery "gigafactory" in Nevada in 
partnership with Panasonic, currently its sole battery supplier.  But to 
meet CEO Elon Musk's stated goal of selling 500,000 cars per year by 
2018-rather than by 2020 as originally planned-Tesla may need additional 
suppliers to achieve the necessary volume.


David Roden - Akron, Ohio, USA
EVDL Administrator

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Re: [EVDL] Off-grid solar house and electric car charging

> The only time high voltage helps is when you need to have long wire
runs...

The operative word  is "long"  And when you wire a house for every room
and for every appliance and for every outlet (whether used fully or not)
then every wire is "long".

The academic argument below is like saying there is nothing wrong with
falling out of an airplane.  Its only when you hit the ground that you
have a problem...

Bob
-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via EV
Sent: Tuesday, June 07, 2016 11:24 PM
To: Larry Gales; Electric Vehicle Discussion List
Subject: Re: [EVDL] Off-grid solar house and electric car charging

Larry Gales via EV wrote:
> Thanks, I was somewhat aware of the increased use of copper, but not
> to the extent that you specify, so it looks like AC is the way to go,
> even for off-grid solar.

Lower voltage means higher current and bigger wires; but it's not as bad
as you think.

First, consider a motor or transformer. You would think that winding it
for a lower voltage / higher current would require more copper... but it
doesn't. Motors and transformers are exactly the same size, have the same
efficiency, same power rating, and use the same amount of copper no matter
what voltage they are built for.

Here's why: If you halve the voltage, you double the current (to get the
same power). But half the voltage requires half the turns. So the wire is
twice as think, but half as long. The total amount of copper thus stays
the same. This only breaks down if the voltage is so low that you need
less than 1 turn, or if the voltage is so high that excessive amounts of
space are taken up by insulation instead of copper.

Now consider a pair of identical 12v batteries. You can wire them in
series (24v), or parallel (12v). For the same power, you'll have the same
current in each battery (since their voltages are all the same).
So, the same wire size to every battery. For the sake of argument, let's
assume you connect a 12" piece of wire to every battery post, and it has
1 milliohm of resistance.

If they're in series, you have a total of 4 feet of wire total, all in
series, and so 4 milliohms of resistance. if the load is 24v at 100 amps,
then this 4 milliohms is burning up I^2R = 100^2 x 0.004 = 40 watts as
heat.

If they're in parallel, the free ends of the + wires connect together, and
the free ends of the - wires connect together. Now you have two parallel
strings, each with 2 feet of wire in it; so each string has half the
resistance or 2 milliohms. But there are two of these strings in parallel,
so the total resistance is 1 milliohm. The same load power is 12v at 200a.
I^2R losses are 200^2 x 0.001 = 40 watts.

Exactly the same size and length of wire, and exactly the same losses!

The same thing happens with PV panels, power semiconductors, and just
about any power devices. Arranging them for low voltage/high current
results in the same losses as arranging them fro high voltage/low current.

The only time high voltage helps is when you need to have long wire runs.
If your PV panels are far from your inverter, then high voltage for the
wires between them will the reduce the amount of copper needed and/or
lower your losses. However, if you're using small low-voltage individual
inverters mounted right on each panel to one big central inverter located
far away, then the small inverters can "win" and use less copper overall.

You have to carefully consider the specifics of the situation, and not
make snap judgements about low voltages being automatically worse.
--
"IC chip performance doubles every 18 months." -- Moore's law "The speed
of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging

2016-06-08 Thread David Kerzel via EV

In example 1 series you have 2 12 inch leads out of the pack.
In example 2 parallel you use all the leads to connect them together and the
12 inch leads out of the pack are missing,  They would add .001 ohm each if
the same size wire which is a second 40 watts.
david

-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via EV
Sent: Tuesday, June 07, 2016 11:24 PM
To: Larry Gales; Electric Vehicle Discussion List
Subject: Re: [EVDL] Off-grid solar house and electric car charging

Larry Gales via EV wrote:
> Thanks, I was somewhat aware of the increased use of copper, but not 
> to the extent that you specify, so it looks like AC is the way to go, 
> even for off-grid solar.

Lower voltage means higher current and bigger wires; but it's not as bad as
you think.

First, consider a motor or transformer. You would think that winding it for
a lower voltage / higher current would require more copper... but it
doesn't. Motors and transformers are exactly the same size, have the same
efficiency, same power rating, and use the same amount of copper no matter
what voltage they are built for.

Here's why: If you halve the voltage, you double the current (to get the
same power). But half the voltage requires half the turns. So the wire is
twice as think, but half as long. The total amount of copper thus stays the
same. This only breaks down if the voltage is so low that you need less than
1 turn, or if the voltage is so high that excessive amounts of space are
taken up by insulation instead of copper.

Now consider a pair of identical 12v batteries. You can wire them in series
(24v), or parallel (12v). For the same power, you'll have the same current
in each battery (since their voltages are all the same). 
So, the same wire size to every battery. For the sake of argument, let's
assume you connect a 12" piece of wire to every battery post, and it has
1 milliohm of resistance.

If they're in series, you have a total of 4 feet of wire total, all in
series, and so 4 milliohms of resistance. if the load is 24v at 100 amps,
then this 4 milliohms is burning up I^2R = 100^2 x 0.004 = 40 watts as heat.

If they're in parallel, the free ends of the + wires connect together, and
the free ends of the - wires connect together. Now you have two parallel
strings, each with 2 feet of wire in it; so each string has half the
resistance or 2 milliohms. But there are two of these strings in parallel,
so the total resistance is 1 milliohm. The same load power is 12v at 200a.
I^2R losses are 200^2 x 0.001 = 40 watts.

Exactly the same size and length of wire, and exactly the same losses!

The same thing happens with PV panels, power semiconductors, and just about
any power devices. Arranging them for low voltage/high current results in
the same losses as arranging them fro high voltage/low current.

The only time high voltage helps is when you need to have long wire runs. If
your PV panels are far from your inverter, then high voltage for the wires
between them will the reduce the amount of copper needed and/or lower your
losses. However, if you're using small low-voltage individual inverters
mounted right on each panel to one big central inverter located far away,
then the small inverters can "win" and use less copper overall.

You have to carefully consider the specifics of the situation, and not make
snap judgements about low voltages being automatically worse.
--
"IC chip performance doubles every 18 months." -- Moore's law "The speed of
software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging

2016-06-08 Thread jerry freedomev via EV

^2R losses are 200^2 x 0.001 = 40 watts.

Exactly the same size and length of wire, and exactly the same losses!

The same thing happens with PV panels, power semiconductors, and just
about any power devices. Arranging them for low voltage/high current
results in the same losses as arranging them fro high voltage/low current.

The only time high voltage helps is when you need to have long wire runs.
If your PV panels are far from your inverter, then high voltage for the
wires between them will the reduce the amount of copper needed and/or
lower your losses. However, if you're using small low-voltage individual
inverters mounted right on each panel to one big central inverter located
far away, then the small inverters can "win" and use less copper overall.

You have to carefully consider the specifics of the situation, and not
make snap judgements about low voltages being automatically worse.
--
"IC chip performance doubles every 18 months." -- Moore's law "The speed
of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging

2016-06-08 Thread Peri Hartman via EV

I think Lee was referring to how you wire the panels together, not the 
house.  You could wire your panels in parallel and, as long as your 
inverter is near the panels, not incur any more line losses than a 
series system.


Peri

-- Original Message --
From: "Robert Bruninga via EV" 
To: "Electric Vehicle Discussion List" 
Sent: 08-Jun-16 5:47:59 AM
Subject: Re: [EVDL] Off-grid solar house and electric car charging


 The only time high voltage helps is when you need to have long wire

runs...

The operative word  is "long"  And when you wire a house for every room
and for every appliance and for every outlet (whether used fully or 
not)

then every wire is "long".

The academic argument below is like saying there is nothing wrong with
falling out of an airplane.  Its only when you hit the ground that you
have a problem...

Bob
-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via 
EV

Sent: Tuesday, June 07, 2016 11:24 PM
To: Larry Gales; Electric Vehicle Discussion List
Subject: Re: [EVDL] Off-grid solar house and electric car charging

Larry Gales via EV wrote:

 Thanks, I was somewhat aware of the increased use of copper, but not
 to the extent that you specify, so it looks like AC is the way to go,
 even for off-grid solar.


Lower voltage means higher current and bigger wires; but it's not as 
bad

as you think.

First, consider a motor or transformer. You would think that winding it
for a lower voltage / higher current would require more copper... but 
it
doesn't. Motors and transformers are exactly the same size, have the 
same
efficiency, same power rating, and use the same amount of copper no 
matter

what voltage they are built for.

Here's why: If you halve the voltage, you double the current (to get 
the
same power). But half the voltage requires half the turns. So the wire 
is

twice as think, but half as long. The total amount of copper thus stays
the same. This only breaks down if the voltage is so low that you need
less than 1 turn, or if the voltage is so high that excessive amounts 
of

space are taken up by insulation instead of copper.

Now consider a pair of identical 12v batteries. You can wire them in
series (24v), or parallel (12v). For the same power, you'll have the 
same

current in each battery (since their voltages are all the same).
So, the same wire size to every battery. For the sake of argument, 
let's
assume you connect a 12" piece of wire to every battery post, and it 
has

1 milliohm of resistance.

If they're in series, you have a total of 4 feet of wire total, all in
series, and so 4 milliohms of resistance. if the load is 24v at 100 
amps,

then this 4 milliohms is burning up I^2R = 100^2 x 0.004 = 40 watts as
heat.

If they're in parallel, the free ends of the + wires connect together, 
and
the free ends of the - wires connect together. Now you have two 
parallel

strings, each with 2 feet of wire in it; so each string has half the
resistance or 2 milliohms. But there are two of these strings in 
parallel,
so the total resistance is 1 milliohm. The same load power is 12v at 
200a.

I^2R losses are 200^2 x 0.001 = 40 watts.

Exactly the same size and length of wire, and exactly the same losses!

The same thing happens with PV panels, power semiconductors, and just
about any power devices. Arranging them for low voltage/high current
results in the same losses as arranging them fro high voltage/low 
current.


The only time high voltage helps is when you need to have long wire 
runs.

If your PV panels are far from your inverter, then high voltage for the
wires between them will the reduce the amount of copper needed and/or
lower your losses. However, if you're using small low-voltage 
individual
inverters mounted right on each panel to one big central inverter 
located
far away, then the small inverters can "win" and use less copper 
overall.


You have to carefully consider the specifics of the situation, and not
make snap judgements about low voltages being automatically worse.
--
"IC chip performance doubles every 18 months." -- Moore's law "The 
speed

of software halves every 18 months." -- Gates' law
--
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Please di

Re: [EVDL] Samsung wises up

[dated]

http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-Samsung-sez-burn-fat-selling-off-fc-s-rolled-into-li-ion-tp4681765.html
EVLN: Samsung sez burn fat> selling-off fc's> $ rolled into li-ion
% Dumping their 100W butane-fc's & focusing on the EV li-ion market, (fuel
cell discussions are OT on the evdl) % 
Samsung SDI Drops Fuel Cell Business To Focus More Intensely On Batteries...
Apr 28 2016


http://www.hydrogenfuelnews.com/tag/samsung-hydrogen-fuel-cell-development/
Samsung SDI to abandon development of hydrogen fuel cells
28 April 2016 ... which it claims has become too expensive to be considered
viable ...


http://www.koreatimes.co.kr/www/news/tech/2016/04/133_202485.html
Samsung to drop fuel cell business
Apr 12, 2016 - Samsung SDI, the battery affiliate of Samsung Group, said
late ... "Samsung SDI decided to drop fuel cell-related business projects,
as the ... 




For EVLN EV-newswire posts use: 
http://evdl.org/evln/


{brucedp.150m.com}

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Re: [EVDL] Off-grid solar house and electric car charging

I thought the original question was about wiring an off grid house for low
voltage DC versus throughout and using all DC appliances and equipment
instead of 120/240 VAC like all other houses

-Original Message-
> I think Lee was referring to how you wire the panels together,
> not the house.  You could wire your panels in parallel and,
> as long as your inverter is near the panels, not incur any more line
> losses > than a series system.


Peri

-- Original Message --
From: "Robert Bruninga via EV" 
To: "Electric Vehicle Discussion List" 
Sent: 08-Jun-16 5:47:59 AM
Subject: Re: [EVDL] Off-grid solar house and electric car charging

>>  The only time high voltage helps is when you need to have long wire
>runs...
>
>The operative word  is "long"  And when you wire a house for every room
>and for every appliance and for every outlet (whether used fully or
>not)  then every wire is "long".
>
>The academic argument below is like saying there is nothing wrong with
>falling out of an airplane.  Its only when you hit the ground that you
>have a problem...
>
>Bob
>-Original Message-
>From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via
>Sent: Tuesday, June 07, 2016 11:24 PM
>To: Larry Gales; Electric Vehicle Discussion List
>Subject: Re: [EVDL] Off-grid solar house and electric car charging
>
>Larry Gales via EV wrote:
>>  Thanks, I was somewhat aware of the increased use of copper,
>> but not to the extent that you specify, so it looks like AC is the
>>  way to go,   even for off-grid solar.
>
>Lower voltage means higher current and bigger wires; but it's not as
>bad as you think.
>
>First, consider a motor or transformer. You would think that winding it
>for a lower voltage / higher current would require more copper... but
>it doesn't. Motors and transformers are exactly the same size, have the
>same efficiency, same power rating, and use the same amount of copper
>no matter what voltage they are built for.
>
>Here's why: If you halve the voltage, you double the current (to get
>the same power). But half the voltage requires half the turns. So the
>wire is twice as think, but half as long. The total amount of copper
>thus stays the same. This only breaks down if the voltage is so low
>that you need less than 1 turn, or if the voltage is so high that
>excessive amounts of space are taken up by insulation instead of
>copper.
>
>Now consider a pair of identical 12v batteries. You can wire them in
>series (24v), or parallel (12v). For the same power, you'll have the
>same current in each battery (since their voltages are all the same).
>So, the same wire size to every battery. For the sake of argument,
>let's assume you connect a 12" piece of wire to every battery post, and
>it has
>1 milliohm of resistance.
>
>If they're in series, you have a total of 4 feet of wire total, all in
>series, and so 4 milliohms of resistance. if the load is 24v at 100
>amps, then this 4 milliohms is burning up I^2R = 100^2 x 0.004 = 40
>watts as heat.
>
>If they're in parallel, the free ends of the + wires connect together,
>and the free ends of the - wires connect together. Now you have two
>parallel strings, each with 2 feet of wire in it; so each string has
>half the resistance or 2 milliohms. But there are two of these strings
>in parallel, so the total resistance is 1 milliohm. The same load power
>is 12v at 200a.
>I^2R losses are 200^2 x 0.001 = 40 watts.
>
>Exactly the same size and length of wire, and exactly the same losses!
>
>The same thing happens with PV panels, power semiconductors, and just
>about any power devices. Arranging them for low voltage/high current
>results in the same losses as arranging them fro high voltage/low
>current.
>
>The only time high voltage helps is when you need to have long wire
>runs.
>If your PV panels are far from your inverter, then high voltage for the
>wires between them will the reduce the amount of copper needed and/or
>lower your losses. However, if you're using small low-voltage
>individual inverters mounted right on each panel to one big central
>inverter located far away, then the small inverters can "win" and use
>less copper overall.
>
>You have to carefully consider the specifics of the situation, and not
>make snap judgements about low voltages being automatically worse.
>--
>"IC chip performance doubles every 18 months." -- Moore's law "The
>speed of software halves every 18 months." -- Gates' law
>--
>Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging


Robert Bruninga via EV wrote:

The only time high voltage helps is when you need to have long wire

runs...

The operative word  is "long"  And when you wire a house for every room
and for every appliance and for every outlet (whether used fully or not)
then every wire is "long".


What is "long" to you may be "short" to others. Let's put numbers on it, 
Robert.


In my house, the longest run from circuit breaker panel to the farthest 
outlet is about 35 feet. Current wiring practices use #12 wire on a 15 
amp circuit. #12 has a resistance of 1.588 milliohms per foot. So this 
35-foot run has a total resistance of 70 feet x 0.001588ohm = 0.111 
ohms. Google tells me that #12-2 with ground is currently selling for 
about $0.28/foot; so 35 feet costs $10.


You're only allowed to load a 15 amp circuit to 12 amps continuously 
(1440 watts). So the worst-case voltage drop is 12a x 0.111ohm = 1.33v, 
and power loss is I^2R = 12^2 x 0.111 = 16 watts. 16w/1440w = 0.011 or 
just over 1% of your power is lost.


24vdc is a common PV panel voltage. Let's assume we simply distributed 
this power directly, through the same 35 feet of #12 wire. (It would be 
silly to do it this way, but just for the sake of argument...)


We have 24v/120v = 1/5th of the voltage, so we need 5 times the current 
to get the same power. The voltage drop will be 5 times more; 1.33v x 5 
= 6.65v. The current is 12 x 5 = 60 amps, and I^2R losses would 25 times 
more, so 16 x 25 = 400 watts. We'd be wasting about 25% of our power in 
wire losses. Besides, #12 wire would overheat and isn't safe at this 
current.


So realistically, we'd increase the wire size; probably to #6. We only 
need 2 wires (not 3) because you don't need a separate ground wire on 
24v systems. Google says #6-2 is $0.87/foot, so the 35-foot run is 
$30.52 ($20 more).


#6 resistance is 0.3951 milliohms/foot, so a 35-foot run is 70 feet x 
0.0003951ohm = 0.01383 ohms. The worst-case voltage drop is 60a x 
0.01383ohm = 0.829v, and power loss is I^2R = 60^2 x 0.01383 = 49.7 
watts. 49.7w/1440w = 0.0345 or about 3.5% of our power is lost.


Bottom line: The 24v approach works fine, but costs $20 more and is 2% 
less efficient. Whether you consider that a little or a lot is a matter 
of opinion.


And... this is the EV list; no one is going to have a 35-foot run in 
their car. And PV panels (or more likely batteries) are a distributed 
source, so you have many small individual wires to each of them anyway; 
not one big cable. Design the system around the situation you've got; 
not with rules of thumb that don't apply to the situation.

--
"IC chip performance doubles every 18 months." -- Moore's law
"The speed of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging


David Kerzel wrote:

In example 1 series you have 2 12 inch leads out of the pack.
In example 2 parallel you use all the leads to connect them together and the
12 inch leads out of the pack are missing,  They would add .001 ohm each if
the same size wire which is a second 40 watts.


View with a fixed-width font like Courier. Ignore the dots; they just 
trick Microsoft into not deleting all the extra spaces.


Example 1 (series), four 12" pieces of wire (the / and \):
+O . . . . . . O . . . . . . O-
. \ . . . . . / \ . . . . . /
. .+ battery - . + battery -

Example 2 (parallel), four 12" pieces of wire (/ and \):
. .+ battery -
. / . . . . . \
.O+ . . . . . -O
. \ . . . . . /
. .+ battery -

Identical wire sizes, wire lengths, and wire resistive losses, 
regardless of whether wired for low voltage or high voltage.


The purpose is not to show that one way or another is always "best". It 
ain't that easy! The point of these examples is that you have to THINK 
about how things are wired, and not just fall for conventional wisdom 
that is often inappropriate or even wrong.

--
"IC chip performance doubles every 18 months." -- Moore's law
"The speed of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging

Just to clarify...

>The only time high voltage helps is when you need to have
> long wire runs [and long means over a few tens of feet]
>
> However, if you're using small low-voltage individual inverters
> mounted right on each panel to one big central inverter located
> far away, then the small inverters can "win" and use less copper
> overall.

Still not true.  The output of microinverters is at 240 VAC  and the average
current in the wires will be double as the same number of panels at 480 VDC.
Further, AC peak currents are 1.4 times higher than DC so the peak currents
(where the losses are) are 2.8 times greater, and since losses in the wire
are proportional to current squared, the losses in the same wire will be
almost 8 times as much.  Hence you always have the choise to either use much
bigger wire, or accept the greater losses at low voltages.

The difference in buying #6 wire instead of #12 is only $180 versus $30.  Or
you can ignore the extra 10% or so losses and use #10 wire.  But over the
life of the system (20 years) the losses in your solar system can add up to
many thousands of dollars.

Maybe I am just being nitpicky, but my solar arrays are all over my yard and
house.  Some runs are over 300 feet!  (shortest is maybe 60').

>You have to carefully consider the specifics of the situation, and not
>make snap judgements about low voltages being automatically worse.

True, just be informed and make your design based on it.Bob
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Re: [EVDL] Off-grid solar house and (series//parallel)

Sorry, this is still misleading in the real world.

> Identical wire sizes, wire lengths, and wire resistive losses,
> regardless of whether wired for low voltage or high voltage.

There is no way you can wire 14 solar panels (10' by 20') array in
parallel with the "same wire sizes and lengths" (and loss) compared to
series.  Physically impossible.  Same is true for a dozen 12v car
batteries.  Impossible to wire them in parallel with the same lengths and
wire sizes (and loss) as series, so your argunment is academically true,
but obfuscates the real world.

The truth is that lower voltage will always require more copper (for the
same losses).  In 1 foot cables between batteries, the difference is
usually not worth worrying about.  But ever since the wars of Edison and
Tesla over a century ago, HV distribution will always take less copper for
the same losses.  But again, copper use is just part of the many overall
design considerations.  And in distribution of power, distance is always
the main variable.  Bob

-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via EV
Sent: Wednesday, June 08, 2016 12:29 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Off-grid solar house and electric car charging

David Kerzel wrote:
> In example 1 series you have 2 12 inch leads out of the pack.
> In example 2 parallel you use all the leads to connect them together
> and the
> 12 inch leads out of the pack are missing,  They would add .001 ohm
> each if the same size wire which is a second 40 watts.

View with a fixed-width font like Courier. Ignore the dots; they just
trick Microsoft into not deleting all the extra spaces.

Example 1 (series), four 12" pieces of wire (the / and \):
+O . . . . . . O . . . . . . O-
. \ . . . . . / \ . . . . . /
. .+ battery - . + battery -

Example 2 (parallel), four 12" pieces of wire (/ and \):
. .+ battery -
. / . . . . . \
.O+ . . . . . -O
. \ . . . . . /
. .+ battery -

Identical wire sizes, wire lengths, and wire resistive losses, regardless
of whether wired for low voltage or high voltage.

The purpose is not to show that one way or another is always "best". It
ain't that easy! The point of these examples is that you have to THINK
about how things are wired, and not just fall for conventional wisdom that
is often inappropriate or even wrong.
--
"IC chip performance doubles every 18 months." -- Moore's law "The speed
of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging


Peri Hartman via EV wrote:

I think Lee was referring to how you wire the panels together, not the
house. You could wire your panels in parallel and, as long as your
inverter is near the panels, not incur any more line losses than a
series system.


Right! PV panels are physically large, even larger than batteries. Thus 
there is inevitably a fair amount of wire needed to connect them together.


We must simply try to locate the source and the load as close together 
as possible. That minimizes the *total* amount of wire (both length and 
cross-sectional area), and that will tend to optimize cost, performance, 
and efficiency. Often, the differences between series/parallel aren't as 
significant as you might think. They can be small enough that other 
factors matter more.


--
"IC chip performance doubles every 18 months." -- Moore's law
"The speed of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging


Robert Bruninga via EV wrote:

Still not true.  The output of microinverters is at 240 VAC  and the average
current in the wires will be double as the same number of panels at 480 VDC.


But each microinverter has its own wire. The total current may be twice 
as much in a 240v system as in a 480v system; but there are twice the 
number of wires, each half the size. You wind up back where you started.



Further, AC peak currents are 1.4 times higher than DC so the peak currents
(where the losses are) are 2.8 times greater


No; AC voltages and currents are normally expressed in RMS 
(Root-Mean-Square). RMS voltages and currents have the *same* effective 
values, voltage drops, and losses as DC. 120vac and 120vdc are 
completely equivalent.



The difference in buying #6 wire instead of #12 is only $180 versus $30.  Or
you can ignore the extra 10% or so losses and use #10 wire.  But over the
life of the system (20 years) the losses in your solar system can add up to
many thousands of dollars.


Sure; it's basically an economic decision. How much can you afford 
up-front, to reduce long-term losses? It's further complicated because 
when you eventually scrap the system, much of the cost of the copper is 
recoverable.


Note that this is the EV discussion list. Besides these tradeoffs, 
weight is also an issue. You may be ahead by deliberately undersizing 
the wire to save weight. The benefit from weight reduction can exceed 
the efficiency loss. Racers know this well!



Maybe I am just being nitpicky, but my solar arrays are all over my yard and
house.  Some runs are over 300 feet!  (shortest is maybe 60').


Ah; no wonder you are so concerned with wire lengths. I definitely 
consider 60-300 feet *long* runs! The PV panels on my house are only 20' 
from my circuit breaker panel.


--
"IC chip performance doubles every 18 months." -- Moore's law
"The speed of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging

Im sorry again, but this is simply not true when expanded to WIRE LOSS.

> No; AC voltages and currents... (Root-Mean-Square).
> RMS voltages and currents have the *same* effective
> values, voltage drops, and losses as DC. 120vac and
> 120vdc are completely equivalent.

Yes, as far as VOLTS and as AMPS as averages are concerned.  Such as
average power.  A 1500W resistor will be 1500W whether on DC or RMS AC.

But the power loss in wires feeding that resistor will have greater loss
on AC because of two factors important in distribution systems:

1) SKIN EFFECT where the AC current is pushed to the outside of the wire
so that not all the wire is carrying the same current.  Thus the wire is
not as effective since not all of its copper is being used in an AC system

2) Peak power losses.  As you note, the RMS current  is the same, but the
PEAK current is 1.4 times higher during the peak of the waveform and since
that is where the most power is delivered that is also where the most loss
occurs in the wire.  So the average power lost in the wire for AC is
almost twice (1.4 squared) the loss in the same wire at DC.

Google it...

That is why the entire industry is looking at DC transmission lines now
that we are finally getting to the point where the up and down conversion
is becomming cost competitive with transformers...

Bob
-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via EV
Sent: Wednesday, June 08, 2016 2:03 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Off-grid solar house and electric car charging

Robert Bruninga via EV wrote:
> Still not true.  The output of microinverters is at 240 VAC  and the
> average current in the wires will be double as the same number of panels
at 480 VDC.

But each microinverter has its own wire. The total current may be twice as
much in a 240v system as in a 480v system; but there are twice the number
of wires, each half the size. You wind up back where you started.

> Further, AC peak currents are 1.4 times higher than DC so the peak
> currents (where the losses are) are 2.8 times greater

No; AC voltages and currents are normally expressed in RMS
(Root-Mean-Square). RMS voltages and currents have the *same* effective
values, voltage drops, and losses as DC. 120vac and 120vdc are completely
equivalent.

> The difference in buying #6 wire instead of #12 is only $180 versus
> $30.  Or you can ignore the extra 10% or so losses and use #10 wire.
> But over the life of the system (20 years) the losses in your solar
> system can add up to many thousands of dollars.

Sure; it's basically an economic decision. How much can you afford
up-front, to reduce long-term losses? It's further complicated because
when you eventually scrap the system, much of the cost of the copper is
recoverable.

Note that this is the EV discussion list. Besides these tradeoffs, weight
is also an issue. You may be ahead by deliberately undersizing the wire to
save weight. The benefit from weight reduction can exceed the efficiency
loss. Racers know this well!

> Maybe I am just being nitpicky, but my solar arrays are all over my
> yard and house.  Some runs are over 300 feet!  (shortest is maybe 60').

Ah; no wonder you are so concerned with wire lengths. I definitely
consider 60-300 feet *long* runs! The PV panels on my house are only 20'
from my circuit breaker panel.

--
"IC chip performance doubles every 18 months." -- Moore's law "The speed
of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging

2016-06-08 Thread Peri Hartman via EV


Robert,

I'm not sure how much effect the Skin Effect has.

But for #2, peak power losses, you also need to consider that part of 
the wave form is *below* the average voltage, thus contributing 
significantly *less* resistance.  You can't just look at the resistance 
caused by the peak voltage.


Thirdly, you note that the industry is looking seriously at a DC-based 
grid.  Do you have any references that claim the reason behind this is 
because of line loss due to resistance?  Or is it for other reasons?  
Even it it is line loss - and this is where Skin Effect may play an 
important role - 1MV is way different than 220V.


Peri

-- Original Message --
From: "Robert Bruninga via EV" 
To: "Electric Vehicle Discussion List" 
Sent: 08-Jun-16 11:53:51 AM
Subject: Re: [EVDL] Off-grid solar house and electric car charging


Im sorry again, but this is simply not true when expanded to WIRE LOSS.


 No; AC voltages and currents... (Root-Mean-Square).
 RMS voltages and currents have the *same* effective
 values, voltage drops, and losses as DC. 120vac and
 120vdc are completely equivalent.


Yes, as far as VOLTS and as AMPS as averages are concerned.  Such as
average power.  A 1500W resistor will be 1500W whether on DC or RMS AC.

But the power loss in wires feeding that resistor will have greater 
loss

on AC because of two factors important in distribution systems:

1) SKIN EFFECT where the AC current is pushed to the outside of the 
wire
so that not all the wire is carrying the same current.  Thus the wire 
is
not as effective since not all of its copper is being used in an AC 
system


2) Peak power losses.  As you note, the RMS current  is the same, but 
the
PEAK current is 1.4 times higher during the peak of the waveform and 
since
that is where the most power is delivered that is also where the most 
loss

occurs in the wire.  So the average power lost in the wire for AC is
almost twice (1.4 squared) the loss in the same wire at DC.

Google it...

That is why the entire industry is looking at DC transmission lines now
that we are finally getting to the point where the up and down 
conversion

is becomming cost competitive with transformers...

Bob
-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via 
EV

Sent: Wednesday, June 08, 2016 2:03 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Off-grid solar house and electric car charging

Robert Bruninga via EV wrote:

 Still not true.  The output of microinverters is at 240 VAC  and the
 average current in the wires will be double as the same number of 
panels

at 480 VDC.

But each microinverter has its own wire. The total current may be twice 
as
much in a 240v system as in a 480v system; but there are twice the 
number

of wires, each half the size. You wind up back where you started.


 Further, AC peak currents are 1.4 times higher than DC so the peak
 currents (where the losses are) are 2.8 times greater


No; AC voltages and currents are normally expressed in RMS
(Root-Mean-Square). RMS voltages and currents have the *same* effective
values, voltage drops, and losses as DC. 120vac and 120vdc are 
completely

equivalent.


 The difference in buying #6 wire instead of #12 is only $180 versus
 $30.  Or you can ignore the extra 10% or so losses and use #10 wire.
 But over the life of the system (20 years) the losses in your solar
 system can add up to many thousands of dollars.


Sure; it's basically an economic decision. How much can you afford
up-front, to reduce long-term losses? It's further complicated because
when you eventually scrap the system, much of the cost of the copper is
recoverable.

Note that this is the EV discussion list. Besides these tradeoffs, 
weight
is also an issue. You may be ahead by deliberately undersizing the wire 
to
save weight. The benefit from weight reduction can exceed the 
efficiency

loss. Racers know this well!


 Maybe I am just being nitpicky, but my solar arrays are all over my
 yard and house.  Some runs are over 300 feet!  (shortest is maybe 
60').


Ah; no wonder you are so concerned with wire lengths. I definitely
consider 60-300 feet *long* runs! The PV panels on my house are only 
20'

from my circuit breaker panel.

--
"IC chip performance doubles every 18 months." -- Moore's law "The 
speed

of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging

2016-06-08 Thread Roger Stockton via EV

Robert Bruninga wrote:

> Yes, as far as VOLTS and as AMPS as averages are concerned.  Such as
> average power.  A 1500W resistor will be 1500W whether on DC or RMS AC.
> 
> But the power loss in wires feeding that resistor will have greater loss
> on AC because of two factors important in distribution systems:
> 
> 1) SKIN EFFECT where the AC current is pushed to the outside of the wire
> so that not all the wire is carrying the same current.  Thus the wire is
> not as effective since not all of its copper is being used in an AC system

The skin depth in copper at 60Hz is 8.47mm; this means that until you are using 
a conductor with a diameter greater than 2 x 8.47mm = 16.94mm (about 0.67"), 
the AC resistance is the same as the DC resistance.



> 2) Peak power losses.  As you note, the RMS current  is the same, but the
> PEAK current is 1.4 times higher during the peak of the waveform and since
> that is where the most power is delivered that is also where the most loss
> occurs in the wire.  So the average power lost in the wire for AC is
> almost twice (1.4 squared) the loss in the same wire at DC.
> 
> Google it...

"For a cyclically alternating electric current, RMS is equal to the value of 
the direct current that would produce the same power dissipation in a resistive 
load."
 - 

Cheers,

Roger.

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Re: [EVDL] Off-grid solar house and electric car charging

2016-06-08 Thread paul dove via EV

 wires connect together. Now you have two parallel
strings, each with 2 feet of wire in it; so each string has half the
resistance or 2 milliohms. But there are two of these strings in parallel,
so the total resistance is 1 milliohm. The same load power is 12v at 200a.
I^2R losses are 200^2 x 0.001 = 40 watts.

Exactly the same size and length of wire, and exactly the same losses!

The same thing happens with PV panels, power semiconductors, and just
about any power devices. Arranging them for low voltage/high current
results in the same losses as arranging them fro high voltage/low current.

The only time high voltage helps is when you need to have long wire runs.
If your PV panels are far from your inverter, then high voltage for the
wires between them will the reduce the amount of copper needed and/or
lower your losses. However, if you're using small low-voltage individual
inverters mounted right on each panel to one big central inverter located
far away, then the small inverters can "win" and use less copper overall.

You have to carefully consider the specifics of the situation, and not
make snap judgements about low voltages being automatically worse.
--
"IC chip performance doubles every 18 months." -- Moore's law "The speed
of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging


Roger Stockton quoted:
"For a cyclically alternating electric current, RMS is equal to the
value of the direct current that would produce the same power
dissipation in a resistive load."
 - 

Roger,
You used the wrong definition. The Wikipedia quote is about the power
delivered to the *load* but the discussion was about the power losses in
the *wire* feeding the load.
The situation is the same problem as with (bad) Power Factor: even
though the average power delivered to the load with bad power factor is
the same, the short and high spikes of current will heat the wires more
than in the case of a good power factor, simply because the loss in the
wire goes with the current squared, so higher peaks (and equal *average*
current) still results in higher losses in the line due to the squaring
of the current peaks in the formula for the power loss.

To use a simple and somewhat excessive example as illustration:
Case A: DC power to an (arbitrary) load: 1 Amp continuous, 1 Ohm line
resistance so 1 Volt drop, meaning 1V * 1A = 1Watt of loss in the line.

Case B: power provided with 10% duty cycle so 10A during 10% of the
period and 0 during 90% of the period. Average current still 1A and same
power delivered to the load as in case A.
However, the line load is still 1 Ohm so the 10A current causes a 10V
drop and thus 100 Watt power is lost in the line during the 10% that the
current is flowing, the average power loss in the line is therefor: 100W
* 10% = 10W
so the average power loss in the line is 10 times as high as in case A
due to the peak current being 10 times as high, even though it is only
flowing 1/10th of the time.

(Note that in case B it is claimed that the same power is delivered to
the load, so this means that the extra power loss in the line must be
delivered by a higher power draw from the source, we are after all
dealing with physics here)

Regards,
Cor.
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Re: [EVDL] Off-grid solar house and electric car charging

I am aware of industry looking at High Voltage DC transmission lines in
two distinct areas: Underseas transportation to islands or between
continents
and for long distance coupling of distribution nets.

The reasons for DC are rather simple and that is that when the
transmission line length becomes relatively long in comparison to the
wavelength of the AC then it may start acting as antenna instead of
transmission line and if the capacitance becomes significant (which
cannot be avoided in underseas transport, in contrast to open lines in
the air) then the losses of an AC line become so large that it makes
sense to go through the hassle of converting the AC to DC, transport it
without the associated capacitance or radiating losses and then convert
back to AC.

Added benefit of DC and the separate conversions from/to AC is that you
don't care about synchronising the two grids that you connect, you
simply transport current through the DC line in either direction and the
two grids can be at different frequency, phase or voltage, it does not
matter.

Today east coast and west coast USA are unconnected, the plans to do so
are using DC lines for all the reasons mentioned before.

Obviously disconnecting a high voltage DC line is an issue, but so is a
high voltage AC line since it does not matter that the voltage and
current goes through zero - once a plasma path in air is created by the
initial arc, it will continue to conduct until the line is disconnected
successfully elsewhere, no matter if it is AC or DC.

Cor van de Water 
Chief Scientist 
Proxim Wireless 

office +1 408 383 7626Skype: cor_van_de_water 
XoIP   +31 87 784 1130private: cvandewater.info 

http://www.proxim.com

This email message (including any attachments) contains confidential and
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-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Peri Hartman
via EV
Sent: Wednesday, June 08, 2016 12:07 PM
To: Robert Bruninga; Electric Vehicle Discussion List
Subject: Re: [EVDL] Off-grid solar house and electric car charging

Robert,

I'm not sure how much effect the Skin Effect has.

But for #2, peak power losses, you also need to consider that part of 
the wave form is *below* the average voltage, thus contributing 
significantly *less* resistance.  You can't just look at the resistance 
caused by the peak voltage.

Thirdly, you note that the industry is looking seriously at a DC-based 
grid.  Do you have any references that claim the reason behind this is 
because of line loss due to resistance?  Or is it for other reasons?  
Even it it is line loss - and this is where Skin Effect may play an 
important role - 1MV is way different than 220V.

Peri

-- Original Message --
From: "Robert Bruninga via EV" 
To: "Electric Vehicle Discussion List" 
Sent: 08-Jun-16 11:53:51 AM
Subject: Re: [EVDL] Off-grid solar house and electric car charging

>Im sorry again, but this is simply not true when expanded to WIRE LOSS.
>
>>  No; AC voltages and currents... (Root-Mean-Square).
>>  RMS voltages and currents have the *same* effective
>>  values, voltage drops, and losses as DC. 120vac and
>>  120vdc are completely equivalent.
>
>Yes, as far as VOLTS and as AMPS as averages are concerned.  Such as
>average power.  A 1500W resistor will be 1500W whether on DC or RMS AC.
>
>But the power loss in wires feeding that resistor will have greater 
>loss
>on AC because of two factors important in distribution systems:
>
>1) SKIN EFFECT where the AC current is pushed to the outside of the 
>wire
>so that not all the wire is carrying the same current.  Thus the wire 
>is
>not as effective since not all of its copper is being used in an AC 
>system
>
>2) Peak power losses.  As you note, the RMS current  is the same, but 
>the
>PEAK current is 1.4 times higher during the peak of the waveform and 
>since
>that is where the most power is delivered that is also where the most 
>loss
>occurs in the wire.  So the average power lost in the wire for AC is
>almost twice (1.4 squared) the loss in the same wire at DC.
>
>Google it...
>
>That is why the entire industry is looking at DC transmission lines now
>that we are finally getting to the point where the up and down 
>conversion
>is becomming cost competitive with transformers...
>
>Bob
>-Original Message-
>From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via 
>EV
>Sent: Wednesday, June 08, 2016 2:03 PM
>To: Electric Vehicle Discussion List
>Subject: Re: [EVDL] Off-grid solar house and electric car charging
>
>Robert Bruninga via EV wrote:
>>  Still not true.  The output of microinverters is at 240 VAC  and the
>>  average current in the wires will be double as the same number of 
>>panels
>at 480

Re: [EVDL] Off-grid solar house and electric car charging

2016-06-08 Thread Seth Rothenberg via EV

It's funny to see this discussion about panels.
I spent 2 hours on the roof yesterday watching
the Solar installer find a roof leak under the
junction box.   (Each person defines his own "fun" :-)
(It took about 4 years to show up in a storm)

(Apparently, they stopped the practice of gluing
the junction box to the roof.   Hopefully they also
stopped making extra holes :-)
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Re: [EVDL] Off-grid solar house and electric car charging

2016-06-08 Thread paul dove via EV

Isn't irrelevant in the USA. We have building codes that must be followed.

  From: Robert Bruninga via EV 
 To: Electric Vehicle Discussion List  
 Sent: Wednesday, June 8, 2016 7:47 AM
 Subject: Re: [EVDL] Off-grid solar house and electric car charging

> The only time high voltage helps is when you need to have long wire
runs...

The operative word  is "long"  And when you wire a house for every room
and for every appliance and for every outlet (whether used fully or not)
then every wire is "long".

The academic argument below is like saying there is nothing wrong with
falling out of an airplane.  Its only when you hit the ground that you
have a problem...

Bob
-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via EV
Sent: Tuesday, June 07, 2016 11:24 PM
To: Larry Gales; Electric Vehicle Discussion List
Subject: Re: [EVDL] Off-grid solar house and electric car charging

Larry Gales via EV wrote:
> Thanks, I was somewhat aware of the increased use of copper, but not
> to the extent that you specify, so it looks like AC is the way to go,
> even for off-grid solar.

Lower voltage means higher current and bigger wires; but it's not as bad
as you think.

First, consider a motor or transformer. You would think that winding it
for a lower voltage / higher current would require more copper... but it
doesn't. Motors and transformers are exactly the same size, have the same
efficiency, same power rating, and use the same amount of copper no matter
what voltage they are built for.

Here's why: If you halve the voltage, you double the current (to get the
same power). But half the voltage requires half the turns. So the wire is
twice as think, but half as long. The total amount of copper thus stays
the same. This only breaks down if the voltage is so low that you need
less than 1 turn, or if the voltage is so high that excessive amounts of
space are taken up by insulation instead of copper.

Now consider a pair of identical 12v batteries. You can wire them in
series (24v), or parallel (12v). For the same power, you'll have the same
current in each battery (since their voltages are all the same).
So, the same wire size to every battery. For the sake of argument, let's
assume you connect a 12" piece of wire to every battery post, and it has
1 milliohm of resistance.

If they're in series, you have a total of 4 feet of wire total, all in
series, and so 4 milliohms of resistance. if the load is 24v at 100 amps,
then this 4 milliohms is burning up I^2R = 100^2 x 0.004 = 40 watts as
heat.

If they're in parallel, the free ends of the + wires connect together, and
the free ends of the - wires connect together. Now you have two parallel
strings, each with 2 feet of wire in it; so each string has half the
resistance or 2 milliohms. But there are two of these strings in parallel,
so the total resistance is 1 milliohm. The same load power is 12v at 200a.
I^2R losses are 200^2 x 0.001 = 40 watts.

Exactly the same size and length of wire, and exactly the same losses!

The same thing happens with PV panels, power semiconductors, and just
about any power devices. Arranging them for low voltage/high current
results in the same losses as arranging them fro high voltage/low current.

The only time high voltage helps is when you need to have long wire runs.
If your PV panels are far from your inverter, then high voltage for the
wires between them will the reduce the amount of copper needed and/or
lower your losses. However, if you're using small low-voltage individual
inverters mounted right on each panel to one big central inverter located
far away, then the small inverters can "win" and use less copper overall.

You have to carefully consider the specifics of the situation, and not
make snap judgements about low voltages being automatically worse.
--
"IC chip performance doubles every 18 months." -- Moore's law "The speed
of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging

I have installed both micro-inverter Solar systems and central inverter
series-string Solar systems, both as a volunteer for SunWork in Palo
Alto.

The series-string system uses the wires already attached to the solar
panels to create a single string (up to 10-12 panels) or two independent
(not connected) strings that each feed independently into the inverter.
This is especially significant if the two strings are oriented towards
different parts of the sky or experience different shading.
The only added wiring is typically from the start and the end of the
string of panels to the central inverter. Typical string is 10 panels,
about 2400Wp of solar at minimum of approx 6A, 400VDC.

The micro-inverter system has the same panel wires, but not plugged into
each other to create a string, rather they are plugged into the micro
inverter which is mounted to the rails below each panel and the 240V
plug from each micro-inverter (they typically come with an AC pigtail
and plug) goes to a special cable that you order with the micro
inverters and which has the mating connectors where the micro inverters
plug into. This special cable strings along all panels, connecting all
micro inverters in parallel and the load to the cable for a 240W panel
is 1A at 240V. So a typical 10
panel small installation means a 10A 240V power running through that
cable which is spliced into standard conduit and wiring at one end of
the string and from there to the service panel.
Since a typical central inverter is also mounted within a few feet from
the service panel, the differences in losses between either solution are
typically very minimal.

The only real big thing, why I would always opt for central inverter, is
that maintenance on an inverter while standing on solid ground is so
much easier than maintenance on an inverter attached to rails on the
roof under a solar panel.
Secondary, the price of micro inverters is not competitive with central
inverter and also the location of a central inverter can be chosen so it
is in a cool spot and has an easy life with plenty of air ventilation
while micro inverters by their nature are hermetically sealed and live
on a hot roof. I hope the designers don't use any Electrolytic caps in
them.

I also hope for people with micro inverters that the designers made sure
that the failure rate is more than 10 times lower than central
inverters, even in hot environments or you will need a lot more times
someone on the roof than someone working on the central inverter.

Another concern (and I work in wireless communication) is that micro
inverters report their status via a broadcast of information that you
need to capture using a dedicated receiver in the home, attached to your
computer or sometimes to the home router. This wireless communication
from the inverters on the roof to the receiver in the home might not
always be reliable, whereas a central inverter can easily be hard-wired
to your home router and be accessed from your computer reliably. If you
want, it can even be hard-wired directly to a computer via RS-485 and a
converter from USB.
Statistics from the solar system may or may not be uploaded to a server.
If not, then you can't typically retrieve the info once the sun is gone
since modern inverters shut down completely without solar input to
minimize nighttime parasitic draw. Unless you add a dedicated DC power
supply that you can manually engage to start up the inverter, you can't
read at night what it did during the day. I hope that micro inverters
efficiency and parasitic draw are much better than the central inverter,
otherwise you end up with a less efficient system overall.

One last and not insignificant concern with micro inverters: These
electronic devices are out there on the outside of the home,
high-frequent switching power all day long and creating interference.
Even though they should be EMC compliant, which means that under certain
circumstances they radiate an amount under a certain threshold, they
will still add noise to the radio environment all day long, which can be
a hindrance to anyone interested in low signal, long distance radio
communication anywhere in the neighborhood of your home. In addition,
each one has a radio beacon that is broadcasting their status all day
long which adds to the emissions, even though that should be confined to
a specific free radio band.

Of course you are free to go with any system you like, I can just share
that I have a central inverter sitting in my garage.

Cor van de Water 
Chief Scientist 
Proxim Wireless 
  
office +1 408 383 7626Skype: cor_van_de_water 
XoIP   +31 87 784 1130private: cvandewater.info 

http://www.proxim.com

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Re: [EVDL] Off-grid solar house and electric car charging


Re RMS: This stuff is tricky. I don't blame folks for being confused.

If you're powering a resistive load, AC RMS and DC are identical. Line 
losses are the same. The resistance in the wire is no different than the 
resistance in the load. The losses and power dissipated in both of them 
are the same for DC as for RMS AC.


This is true as long as the current waveform is sinusoidal. Yes, the 
loss is doubled during the peaks; but it is zero during the 
zero-crossings. The losses averaged over a complete cycle are exactly 
the same as for the DC case. This is the whole point of using RMS values 
for AC.


Now, if you're powering some *bad* load with a high crest factor (like a 
non-PFC switching power supply), the current is *not* sinusoidal. It has 
a drastically higher peak, and then is zero for most of the rest of the 
cycle. In this case, the line losses are indeed higher.


As for skin effect, it is negligible at 60hz. It only matters if you are 
dealing with high frequencies, or huge non-stranded conductors.


--
"IC chip performance doubles every 18 months." -- Moore's law
"The speed of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging

2016-06-08 Thread Roger Stockton via EV

Cor van de Water wrote:

> Roger,
> You used the wrong definition. The Wikipedia quote is about the power
> delivered to the *load* but the discussion was about the power losses in
> the *wire* feeding the load.

No; just as the power dissipated in a resistive load remains the same, the 
power dissipated in the wire feeding the load remains the same.

To see that this must be true, consider the case of a source connected to a 
non-zero load by wires with zero resistance: the dissipation in the load is the 
same for 1A DC or 1Arms.

Now, consider a zero-ohm load connected to the source by wires with non-zero 
resistance: the dissipation in the wires is the same for 1A DC or 1Arms.

The principle of superposition allows us to see that this situation holds for 
any combination of load and wire resistances: 1A DC and 1Arms will dissipate 
the same energy in the wires to the load, and they also dissipate the same 
energy in the load, though of course the amounts dissipated in the wire or load 
depends upon their respective resistance.

> To use a simple and somewhat excessive example as illustration:
> Case A: DC power to an (arbitrary) load: 1 Amp continuous, 1 Ohm line
> resistance so 1 Volt drop, meaning 1V * 1A = 1Watt of loss in the line.
> 
> Case B: power provided with 10% duty cycle so 10A during 10% of the
> period and 0 during 90% of the period. Average current still 1A and same
> power delivered to the load as in case A.
> However, the line load is still 1 Ohm so the 10A current causes a 10V
> drop and thus 100 Watt power is lost in the line during the 10% that the
> current is flowing, the average power loss in the line is therefor: 100W
> * 10% = 10W
> so the average power loss in the line is 10 times as high as in case A
> due to the peak current being 10 times as high, even though it is only
> flowing 1/10th of the time.

No.  You are confusing average with RMS; the two are not necessarily the same.

The RMS value of your 10% duty 10A peak square wave is 3.16Arms, and this will 
indeed have higher I2R loss than a 1A DC current.

For your 10A peak square wave to have an RMS value of 1A, it needs a duty cycle 
of 1%:
 RMS = peak * sqrt(duty cycle); average = peak * duty cycle.

Cheers,

Roger.
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Re: [EVDL] Off-grid solar house and electric car charging

Ah, my bad, you are correct - I got confused with power factor concerns
but indeed for pure sine AC the RMS will make AC power identical to DC
power in both load and wires. Thanks for clarifying and setting me
straight!

Cor van de Water 
Chief Scientist 
Proxim Wireless 

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-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Roger Stockton
via EV
Sent: Wednesday, June 08, 2016 2:08 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Off-grid solar house and electric car charging

Cor van de Water wrote:

> Roger,
> You used the wrong definition. The Wikipedia quote is about the power
> delivered to the *load* but the discussion was about the power losses
in
> the *wire* feeding the load.

No; just as the power dissipated in a resistive load remains the same,
the power dissipated in the wire feeding the load remains the same.

To see that this must be true, consider the case of a source connected
to a non-zero load by wires with zero resistance: the dissipation in the
load is the same for 1A DC or 1Arms.

Now, consider a zero-ohm load connected to the source by wires with
non-zero resistance: the dissipation in the wires is the same for 1A DC
or 1Arms.

The principle of superposition allows us to see that this situation
holds for any combination of load and wire resistances: 1A DC and 1Arms
will dissipate the same energy in the wires to the load, and they also
dissipate the same energy in the load, though of course the amounts
dissipated in the wire or load depends upon their respective resistance.

> To use a simple and somewhat excessive example as illustration:
> Case A: DC power to an (arbitrary) load: 1 Amp continuous, 1 Ohm line
> resistance so 1 Volt drop, meaning 1V * 1A = 1Watt of loss in the
line.
> 
> Case B: power provided with 10% duty cycle so 10A during 10% of the
> period and 0 during 90% of the period. Average current still 1A and
same
> power delivered to the load as in case A.
> However, the line load is still 1 Ohm so the 10A current causes a 10V
> drop and thus 100 Watt power is lost in the line during the 10% that
the
> current is flowing, the average power loss in the line is therefor:
100W
> * 10% = 10W
> so the average power loss in the line is 10 times as high as in case A
> due to the peak current being 10 times as high, even though it is only
> flowing 1/10th of the time.

No.  You are confusing average with RMS; the two are not necessarily the
same.

The RMS value of your 10% duty 10A peak square wave is 3.16Arms, and
this will indeed have higher I2R loss than a 1A DC current.

For your 10A peak square wave to have an RMS value of 1A, it needs a
duty cycle of 1%:
 RMS = peak * sqrt(duty cycle); average = peak * duty cycle.

Cheers,

Roger.
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Re: [EVDL] Off-grid solar house and electric car charging

helps is when you need to have long wire runs.
If your PV panels are far from your inverter, then high voltage for the
wires between them will the reduce the amount of copper needed and/or
lower your losses. However, if you're using small low-voltage individual
inverters mounted right on each panel to one big central inverter located
far away, then the small inverters can "win" and use less copper overall.

You have to carefully consider the specifics of the situation, and not
make snap judgements about low voltages being automatically worse.
--
"IC chip performance doubles every 18 months." -- Moore's law "The speed
of software halves every 18 months." -- Gates' law
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: [EVDL] Off-grid solar house and electric car charging

Ah, my bad.  I was transmorgafying the limitations of peak voltage which
can allow greater power delivery on DC lines than AC.  That is,  a 240 VAC
line has peak voltages of 330 volts.  As the voltage rating of the line
becomes an issue, then a DC line can operate at that higher voltage and
deliver 1.4 times more power than the AC system while keeping within the
maximum voltage spec.  (ignoreing transients of course)..

So you are right.  Argument does not apply here since most wiring is rated
at 600 volts well above the 240 VAC peaks.
Bob

-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Roger Stockton
via EV
Sent: Wednesday, June 08, 2016 3:21 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Off-grid solar house and electric car charging

Robert Bruninga wrote:

> Yes, as far as VOLTS and as AMPS as averages are concerned.  Such as
> average power.  A 1500W resistor will be 1500W whether on DC or RMS AC.
>
> But the power loss in wires feeding that resistor will have greater
> loss on AC because of two factors important in distribution systems:
>
> 1) SKIN EFFECT where the AC current is pushed to the outside of the
> wire so that not all the wire is carrying the same current.  Thus the
> wire is not as effective since not all of its copper is being used in
> an AC system

The skin depth in copper at 60Hz is 8.47mm; this means that until you are
using a conductor with a diameter greater than 2 x 8.47mm = 16.94mm (about
0.67"), the AC resistance is the same as the DC resistance.

> 2) Peak power losses.  As you note, the RMS current  is the same, but
> the PEAK current is 1.4 times higher during the peak of the waveform
> and since that is where the most power is delivered that is also where
> the most loss occurs in the wire.  So the average power lost in the
> wire for AC is almost twice (1.4 squared) the loss in the same wire at
DC.
>
> Google it...

"For a cyclically alternating electric current, RMS is equal to the value
of the direct current that would produce the same power dissipation in a
resistive load."
 - 

Cheers,

Roger.

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Re: [EVDL] Off-grid solar house and (series//parallel)