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

[Lee Hart via EV]

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] 12v tales

[Cruisin via EV]

Do NOT use a Li-ion 12vdc battery in your Tesla. It probably is a 12vdc, not
a 13.5vdc like the lead/acid is. You will destroy the Li-ion.

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Re: [EVDL] 12v tales

[Michael Ross via EV]

I have used a number of Meanwell 110VAC to 5, 12 and 24 VDC.  They seem
very good, and inexpensive. I always chuckle at the name.

On Tue, Jun 7, 2016 at 5:03 PM, Cor van de Water via EV <ev@lists.evdl.org>
wrote:

> Also,
> one particular thing that I like a lot about Meanwell is that they
> actually specify their power supplies to work from DC. Usually 130 - 370
> VDC.
> And it is a Taiwanese company, so they tend to supply higher quality
> than China.
> The SP-750 has a built-in PFC front end, not important for DC
> application
> but it tells you that when you happen to use it on AC, it will have a
> very good power factor and thus have minimal current draw, important if
> you need to share a line with other loads.
> http://www.meanwell.com/webapp/product/search.aspx?prod=sp-750
> Regards,
>
> 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
> proprietary information of Proxim Wireless Corporation.  If you received
> this message in error, please delete it and notify the sender.  Any
> unauthorized use, disclosure, distribution, or copying of any part of
> this message is prohibited.
>
>
> -Original Message-
> From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Peter C.
> Thompson via EV
> Sent: Tuesday, June 07, 2016 1:00 PM
> To: ev@lists.evdl.org
> Subject: Re: [EVDL] 12v tales
>
> Completely agree - with a small reservation:  You don't want to use a
> no-name converter in your expensive car.  I made that mistake once,
> won't do it again.  I will only use name-brand equipment.  In my EV's
> case, I'm using the Meanwell 750W 15V (SP-750-15).  I've turned the
> voltage down to 13.5V, and it works very well.  The previous one somehow
>
> had ingested some metal and literally blew up.
>
> Cheers!
>
> On 6/7/16 12:17 PM, Jan Steinman via EV wrote:
> > One thing I haven't seen mentioned here is that power converters
> specifically designed to convert traction pack voltage to 12 VDC are
> expensive, whereas generic power supplies that do the same thing for
> line voltage are cheap.
> >
> > Almost any "universal" switching power supply designed to work from
> 120 to 240 VAC without changing jumpers or switches IS a traction pack
> power converter! The main difference is a full-wave bridge on the input,
> which means you don't even have to worry about polarity when hooking it
> up!
> >
> > These things are dirt cheap from China, like 12 cents a watt or about
> $1 per amp. Here's a bunch of them:
> >
> http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2053587.m570.l1313.TR0
> .TRC0.H1.X13.8v+40a+power+supply.TRS0&_nkw=13.8v+40a+power+supply&_sacat
> =0
> >
> >  There is a standard wrong belief about the physics of energy and
> the economy; it is the belief we can somehow train the economy to get
> along without much energy. -- Gail Tverberg
> <http://www.lmgtfy.com/?q=Gail+Tverberg>
> >  Jan Steinman, EcoReality Co-op <http://www.ecoreality.org/> 
> >
> > ___
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>
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>


-- 
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<http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html>

A public-opinion poll is no substitute for thought.
*Warren Buffet*

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Re: [EVDL] 12v tales

[Cor van de Water via EV]

Also,
one particular thing that I like a lot about Meanwell is that they
actually specify their power supplies to work from DC. Usually 130 - 370
VDC.
And it is a Taiwanese company, so they tend to supply higher quality
than China.
The SP-750 has a built-in PFC front end, not important for DC
application
but it tells you that when you happen to use it on AC, it will have a
very good power factor and thus have minimal current draw, important if
you need to share a line with other loads.
http://www.meanwell.com/webapp/product/search.aspx?prod=sp-750
Regards,

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
proprietary information of Proxim Wireless Corporation.  If you received
this message in error, please delete it and notify the sender.  Any
unauthorized use, disclosure, distribution, or copying of any part of
this message is prohibited.


-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Peter C.
Thompson via EV
Sent: Tuesday, June 07, 2016 1:00 PM
To: ev@lists.evdl.org
Subject: Re: [EVDL] 12v tales

Completely agree - with a small reservation:  You don't want to use a 
no-name converter in your expensive car.  I made that mistake once, 
won't do it again.  I will only use name-brand equipment.  In my EV's 
case, I'm using the Meanwell 750W 15V (SP-750-15).  I've turned the 
voltage down to 13.5V, and it works very well.  The previous one somehow

had ingested some metal and literally blew up.

Cheers!

On 6/7/16 12:17 PM, Jan Steinman via EV wrote:
> One thing I haven't seen mentioned here is that power converters
specifically designed to convert traction pack voltage to 12 VDC are
expensive, whereas generic power supplies that do the same thing for
line voltage are cheap.
>
> Almost any "universal" switching power supply designed to work from
120 to 240 VAC without changing jumpers or switches IS a traction pack
power converter! The main difference is a full-wave bridge on the input,
which means you don't even have to worry about polarity when hooking it
up!
>
> These things are dirt cheap from China, like 12 cents a watt or about
$1 per amp. Here's a bunch of them:
>
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2053587.m570.l1313.TR0
.TRC0.H1.X13.8v+40a+power+supply.TRS0&_nkw=13.8v+40a+power+supply&_sacat
=0
>
>  There is a standard wrong belief about the physics of energy and
the economy; it is the belief we can somehow train the economy to get
along without much energy. -- Gail Tverberg

>  Jan Steinman, EcoReality Co-op  
>
> ___
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> Please discuss EV drag racing at NEDRA
(http://groups.yahoo.com/group/NEDRA)
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Re: [EVDL] 12v tales

[EVDL Administrator via EV]

On 7 Jun 2016 at 12:17, Jan Steinman via EV wrote:

> Almost any oeuniversal switching power supply designed to work from 120 to
> 240 VAC without changing jumpers or switches IS a traction pack power
> converter! The main difference is a full-wave bridge on the input, which means
> you don't even have to worry about polarity when hooking it up!
> 

For years, EV converters used Todd marine chargers as DC:DC converters. When 
Todd Engineering hung it up, they turned to Iota power supplies.

http://www.evdl.org/pages/iotamods.html

As the page above suggests, neither made an especially reliable DC:DC 
converter.  A road vehicle tends to be a hostile environment for electronics 
and DC:DCs need to be ruggedized and weather-protected.

> These things are dirt cheap from China

Better order a half-dozen or so.  Put one under the hood, and you can expect 
service life commensurate with the price.

David Roden - Akron, Ohio, USA
EVDL Administrator

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Re: [EVDL] 12v tales

[Peter C. Thompson via EV]

Completely agree - with a small reservation:  You don't want to use a 
no-name converter in your expensive car.  I made that mistake once, 
won't do it again.  I will only use name-brand equipment.  In my EV's 
case, I'm using the Meanwell 750W 15V (SP-750-15).  I've turned the 
voltage down to 13.5V, and it works very well.  The previous one somehow 
had ingested some metal and literally blew up.


Cheers!

On 6/7/16 12:17 PM, Jan Steinman via EV wrote:

One thing I haven’t seen mentioned here is that power converters specifically 
designed to convert traction pack voltage to 12 VDC are expensive, whereas 
generic power supplies that do the same thing for line voltage are cheap.

Almost any “universal” switching power supply designed to work from 120 to 240 
VAC without changing jumpers or switches IS a traction pack power converter! 
The main difference is a full-wave bridge on the input, which means you don’t 
even have to worry about polarity when hooking it up!

These things are dirt cheap from China, like 12 cents a watt or about $1 per 
amp. Here’s a bunch of them:

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2053587.m570.l1313.TR0.TRC0.H1.X13.8v+40a+power+supply.TRS0&_nkw=13.8v+40a+power+supply&_sacat=0

 There is a standard wrong belief about the physics of energy and the economy; it 
is the belief we can somehow train the economy to get along without much energy. -- 
Gail Tverberg 
 Jan Steinman, EcoReality Co-op  

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

[Haudy Kazemi via EV]

I would agree. Lower priced mass produced commodity AC appliances and lower 
wiring/switch/outlet costs will make up for the inverter inefficiencies. Keep 
in mind the amount of useful energy that you need to get out of a system and 
then choose components that will get you there. Max technical efficiency (kWh 
usefully used vs kWh produced by array, or kWh produced/sq. m) is unlikely to 
match max economic efficiency ($/kWh), rather there will be a range of choices 
with tradeoffs, some large, some small. 

Even if you increase the size of your PV array by 10% to offset the 
inverter...you're only talking two extra 250 watt modules (500 W total) on 5 kW 
system. Parts cost can be under $1000 here ($2/watt). (You could also try 
increasing the array size to offset the losses from using a bit smaller DC 
wiring, if you really didn't want AC involved. There is going to be a financial 
sweet spot between various array sizes and the losses associated with a chosen 
wire size.)

Another consideration: future inspectors and owners will likely appreciate the 
use of standardized equipment and techniques.

The math may be a bit different if the electric loads are minimal (e.g. only 
efficient lights) and/or distances short (small cabin/trailer).


On June 7, 2016 11:10:49 AM CDT, Larry Gales via EV <ev@lists.evdl.org> 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.
>
>On Tue, Jun 7, 2016 at 9:06 AM, robert winfield via EV
><ev@lists.evdl.org>
>wrote:
>
>> my inverter (Omnion 2200) has 2 legs. +/- 186v DC (~370v) small
>wires.,
>> inverted to 110v AC about ~8 amps with a 20 amp circuit breaker (made
>back
>> around 1995 - 1997 or so)
>>
>>   From: Robert Bruninga via EV <ev@lists.evdl.org>
>>  To: Electric Vehicle Discussion List <ev@lists.evdl.org>
>>  Sent: Tuesday, June 7, 2016 10:39 AM
>>  Subject: Re: [EVDL] Off-grid solar house and electric car charging
>>
>> > If you build an off-grid solar house and use it for both your house
>> > and charging your electric car, are there any disadvantages for
>using
>> > DC current (household appliances can all be converted to DC) and
>> > avoiding AC since you are off the grid?  You avoid the cost,
>> > maintenance, and (slight) inefficiency of inverters, but are there
>> > significant disadvantages to this approach?
>>
>> A big question is what voltage.  Home solar typically uses high
>voltage
>> 300 to 600 VDC so that currents are less and smaller copper wire can
>be
>> used (think #12 standard wire).
>>
>> Remote, Off -grid DC systems typically operate no higher than 48
>volts.
>> Right there is a 10 to 1 drop in voltage so a 100 to 1 increase in
>cable
>> losses.  Now think big battery cables everywhere and a huge
>investment in
>> copper.
>>
>> Some people then drop to 12v to use many common 12 camping
>accessories to
>> live by.  That then further multiplies wire losses by another eight
>to one
>> factor, or almost 800 times more losses for the same wire.
>>
>> So In most cases, it is far, far easier to accept the 5% Inverter
>lossess
>> and keep your house at the 120 VAC standard so you can use all
>existing
>> home wiring techniques and all existing home appliances and all
>existing
>> electrical things in the home than to deal with ALL specialized much
>more
>> expensive DC appliances and HUGELY expensive specialized wiring.
>>
>> Bob
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>
>
>-- 
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Re: [EVDL] Current limiting

[paul dove via EV]

I was just saying there is no need to speculate.It's just math and you can put 
a variable resistor in there and control the current flow while monitoring with 
a meter. 


  From: Bill Collins <ph...@bill-collins.net>
 To: paul dove <dov...@bellsouth.net>; ev@lists.evdl.org; 
ev-requ...@lists.evdl.org 
 Sent: Tuesday, June 7, 2016 8:40 AM
 Subject: Re: [EVDL] Current limiting
   
That would be an extremely short lived event. Once current starts to flow, delta
voltage will decrease rapidly.

> On June 7, 2016 at 9:33 AM paul dove <dov...@bellsouth.net> wrote:
> 
> 
> Easy to calculate
> V=IR or I=V/R
> R should be very small in the case of connecting with wires or contactors etc.
> So if the delta voltage is 2 volts and R=0.1 ohms I=20amps.
> Easy to see that currents can get very high quickly as the delta V between
> batteries grows.
> A variable resistor could be inserted to control the current.
> In the case of my care fully charge is 149.6 volts fully empty can be as low
> as 110 volts.
> delta V = 39.6 volts  if R=0.1 ohms then I =396 amps a 500 ohm resistor drops
> that to 80mA.
> 
> 
> 
>      From: Bill Collins via EV <ev@lists.evdl.org>
>  To: ev@lists.evdl.org; ev-requ...@lists.evdl.org 
>  Sent: Tuesday, June 7, 2016 7:20 AM
>  Subject: Re: [EVDL] Current limiting
>    
> The resting voltage of a lead acid battery is significantly lower than the
> voltage required to charge it. For example: a fully charged 12 volt battery
> has
> a resting voltage of 12.6, but will not draw much current unless you apply
> 13.5
> volts or so. This means that when you connect two batteries with different
> states of charge, less current flows than many people think.
> 
> Bill
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> 
>

  
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Re: [EVDL] 12v tales

[Jan Steinman via EV]

One thing I haven’t seen mentioned here is that power converters specifically 
designed to convert traction pack voltage to 12 VDC are expensive, whereas 
generic power supplies that do the same thing for line voltage are cheap.

Almost any “universal” switching power supply designed to work from 120 to 240 
VAC without changing jumpers or switches IS a traction pack power converter! 
The main difference is a full-wave bridge on the input, which means you don’t 
even have to worry about polarity when hooking it up!

These things are dirt cheap from China, like 12 cents a watt or about $1 per 
amp. Here’s a bunch of them:

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2053587.m570.l1313.TR0.TRC0.H1.X13.8v+40a+power+supply.TRS0&_nkw=13.8v+40a+power+supply&_sacat=0

 There is a standard wrong belief about the physics of energy and the 
economy; it is the belief we can somehow train the economy to get along without 
much energy. -- Gail Tverberg 
 Jan Steinman, EcoReality Co-op  

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Re: [EVDL] Lead Acid charging...

[Roland via EV]

   
Hello Bob,

 

As the battery discharges, the electrolyte level will drop which is normal.  Do 
not add distill water in a discharge battery.  When you charge the battery, the 
electrolyte level will rise.

 

If the electrolyte is below the plates, then add just enough water to get to 
the top of the plates.  If you add more water in a discharge state, then you 
may be changing the specific gravity to a lower reading when full charge.   

 

Back in the 50's. I work in a military battery shop.  The specific gravity of 
theses type of batteries was at 1.300 sg at full charge at a voltage of 13.34 
volts after rest.

 

Today, the specific gravity is normally set at 1.275 sg for deep cell batteries 
and 1.265 sg for a starter battery.  The reason they use a lower specific 
gravity is that the acid is not so hard on the pasted plates making a longer 
life.

 

After charging your batteries to 1.275 sg, then finish adding the distill water 
to the bottom of the fill tube.  You will note that the fill tubes have a split 
cut in them.  Do not fill above the split fill tube.  The reason for the splits 
tubes is this allows for the electrolyte vapor to flow back down into the 
cells.  

 

If you cannot get your batteries to 1.275 sg, then what happens over time, when 
a person adds too much water, the specific gravity becomes lower.  It is 
possible to rebalance the electrolyte by adding sulfuric acid that has a 
specific gravity of 1.800 sg.  The method to do this, is to pull out a ounce 
electrolyte and add the 1.800 acid.  

 

Then try charging it to see if the electrolyte specific gravity will rise.  
Check the electrolyte specific gravity and repeat this process until you are 
satisfied.

 

If you have a commercial battery shop, then you can take the batteries to them 
and have them do a analyzing test on them.  Normally gulf cart shops have all 
the equipment and supplies to do this job.  

 

Roland  

 

 


- Original Message - 

From: Robert Bruninga via EV<mailto:ev@lists.evdl.org> 

To: Electric Vehicle Discussion List<mailto:ev@lists.evdl.org> 

Sent: Tuesday, June 07, 2016 8:21 AM

Subject: [EVDL] Lead Acid charging...



Finally, Back to Lead acid and a FOUR WIRE EV!  (Something I can
maintain)!
(4 wires, means 2 from the battery, and 2 to the motor and a controller in
the middle.  Done)...

I have given up on modern EV's (two THINKs) who are BRICKS because the
computer in them thinks something is wrong and they want to "call home"
but there is no "home to call" (they are out of business).  And I HATE
trying to hack an unknown embedded CPU... I prefer turning wrenches and
pots

Anyway, I pulled my old converted Honda Civic (ten Lead Acid) out of the
weeds last night and of course, having been sitting for at least two
years, the batteries were dead and would not take a charge form the
installed charger.  SO I moved through each one with a small parallel 12v
battery and a normal 12v charger.  The battery helped convince the
portable 12v charger that there was a working battery until the charge got
started, then I could move on to the next battery.

Now they are all hissing and bubbling away.  And after maybe 12 hours (on
and off, since I only charge while I am nearby and can monitor them),
anyway now, the charge is finally beginning to taper from the original
9.2A down to about 7A.  Then I had to come to work.  Maybe this evening
they will reach full charge and the charge will further taper.

All the cells had water over the plates, some higher than others, so I now
have them all topped off.

I know that long-term sulfation is a problem.  But these batteries were
close to charged when they were abandoned more than a year ago.  So they
did not start their long abandonment discharged, but did so over time.

So any opinions on recovery?

Bob
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Re: [EVDL] Current limiting

[Lee Hart via EV]

Bill Collins via EV wrote:

The resting voltage of a lead acid battery is significantly lower than the
voltage required to charge it. For example: a fully charged 12 volt battery has
a resting voltage of 12.6, but will not draw much current unless you apply 13.5
volts or so. This means that when you connect two batteries with different
states of charge, less current flows than many people think.


The steady-state current is indeed fairly low. But the *peak* current 
when you first connect them can be very high. They also act like huge 
many-farad capacitors. The peak current is approximately their voltage 
difference (V1-V2) divided by their equivalent internal resistance 
(R1+R2). Since the voltage difference can easily exceed 1 volt, and the 
internal resistance is as low as a few milliohms for AGMs, I've measured 
well over 100 amps on several occasions.


Usually, the wire you use to connect the two batteries has significant 
resistance; this limits the peak current. But if you have big wires and 
are closing the circuit with a good switch or contactor, the peak 
current can damage its contacts.


--
"IC chip performance doubles every 18 months." -- Moore's law
"The speed of software halves every 18 months." -- Gates' law
--
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Re: [EVDL] Off-grid solar house and electric car charging

[Larry Gales via EV]

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.

On Tue, Jun 7, 2016 at 9:06 AM, robert winfield via EV <ev@lists.evdl.org>
wrote:

> my inverter (Omnion 2200) has 2 legs. +/- 186v DC (~370v) small wires.,
> inverted to 110v AC about ~8 amps with a 20 amp circuit breaker (made back
> around 1995 - 1997 or so)
>
>   From: Robert Bruninga via EV <ev@lists.evdl.org>
>  To: Electric Vehicle Discussion List <ev@lists.evdl.org>
>  Sent: Tuesday, June 7, 2016 10:39 AM
>  Subject: Re: [EVDL] Off-grid solar house and electric car charging
>
> > If you build an off-grid solar house and use it for both your house
> > and charging your electric car, are there any disadvantages for using
> > DC current (household appliances can all be converted to DC) and
> > avoiding AC since you are off the grid?  You avoid the cost,
> > maintenance, and (slight) inefficiency of inverters, but are there
> > significant disadvantages to this approach?
>
> A big question is what voltage.  Home solar typically uses high voltage
> 300 to 600 VDC so that currents are less and smaller copper wire can be
> used (think #12 standard wire).
>
> Remote, Off -grid DC systems typically operate no higher than 48 volts.
> Right there is a 10 to 1 drop in voltage so a 100 to 1 increase in cable
> losses.  Now think big battery cables everywhere and a huge investment in
> copper.
>
> Some people then drop to 12v to use many common 12 camping accessories to
> live by.  That then further multiplies wire losses by another eight to one
> factor, or almost 800 times more losses for the same wire.
>
> So In most cases, it is far, far easier to accept the 5% Inverter lossess
> and keep your house at the 120 VAC standard so you can use all existing
> home wiring techniques and all existing home appliances and all existing
> electrical things in the home than to deal with ALL specialized much more
> expensive DC appliances and HUGELY expensive specialized wiring.
>
> Bob
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>
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>
>


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

[robert winfield via EV]

my inverter (Omnion 2200) has 2 legs. +/- 186v DC (~370v) small wires., 
inverted to 110v AC about ~8 amps with a 20 amp circuit breaker (made back 
around 1995 - 1997 or so)

  From: Robert Bruninga via EV <ev@lists.evdl.org>
 To: Electric Vehicle Discussion List <ev@lists.evdl.org> 
 Sent: Tuesday, June 7, 2016 10:39 AM
 Subject: Re: [EVDL] Off-grid solar house and electric car charging
   
> If you build an off-grid solar house and use it for both your house
> and charging your electric car, are there any disadvantages for using
> DC current (household appliances can all be converted to DC) and
> avoiding AC since you are off the grid?  You avoid the cost,
> maintenance, and (slight) inefficiency of inverters, but are there
> significant disadvantages to this approach?

A big question is what voltage.  Home solar typically uses high voltage
300 to 600 VDC so that currents are less and smaller copper wire can be
used (think #12 standard wire).

Remote, Off -grid DC systems typically operate no higher than 48 volts.
Right there is a 10 to 1 drop in voltage so a 100 to 1 increase in cable
losses.  Now think big battery cables everywhere and a huge investment in
copper.

Some people then drop to 12v to use many common 12 camping accessories to
live by.  That then further multiplies wire losses by another eight to one
factor, or almost 800 times more losses for the same wire.

So In most cases, it is far, far easier to accept the 5% Inverter lossess
and keep your house at the 120 VAC standard so you can use all existing
home wiring techniques and all existing home appliances and all existing
electrical things in the home than to deal with ALL specialized much more
expensive DC appliances and HUGELY expensive specialized wiring.

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

[Robert Bruninga via EV]

> If you build an off-grid solar house and use it for both your house
> and charging your electric car, are there any disadvantages for using
> DC current (household appliances can all be converted to DC) and
> avoiding AC since you are off the grid?  You avoid the cost,
> maintenance, and (slight) inefficiency of inverters, but are there
> significant disadvantages to this approach?

A big question is what voltage.  Home solar typically uses high voltage
300 to 600 VDC so that currents are less and smaller copper wire can be
used (think #12 standard wire).

Remote, Off -grid DC systems typically operate no higher than 48 volts.
Right there is a 10 to 1 drop in voltage so a 100 to 1 increase in cable
losses.  Now think big battery cables everywhere and a huge investment in
copper.

Some people then drop to 12v to use many common 12 camping accessories to
live by.  That then further multiplies wire losses by another eight to one
factor, or almost 800 times more losses for the same wire.

So In most cases, it is far, far easier to accept the 5% Inverter lossess
and keep your house at the 120 VAC standard so you can use all existing
home wiring techniques and all existing home appliances and all existing
electrical things in the home than to deal with ALL specialized much more
expensive DC appliances and HUGELY expensive specialized wiring.

Bob
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[EVDL] Lead Acid charging...

[Robert Bruninga via EV]

Finally, Back to Lead acid and a FOUR WIRE EV!  (Something I can
maintain)!
(4 wires, means 2 from the battery, and 2 to the motor and a controller in
the middle.  Done)...

I have given up on modern EV's (two THINKs) who are BRICKS because the
computer in them thinks something is wrong and they want to "call home"
but there is no "home to call" (they are out of business).  And I HATE
trying to hack an unknown embedded CPU... I prefer turning wrenches and
pots

Anyway, I pulled my old converted Honda Civic (ten Lead Acid) out of the
weeds last night and of course, having been sitting for at least two
years, the batteries were dead and would not take a charge form the
installed charger.  SO I moved through each one with a small parallel 12v
battery and a normal 12v charger.  The battery helped convince the
portable 12v charger that there was a working battery until the charge got
started, then I could move on to the next battery.

Now they are all hissing and bubbling away.  And after maybe 12 hours (on
and off, since I only charge while I am nearby and can monitor them),
anyway now, the charge is finally beginning to taper from the original
9.2A down to about 7A.  Then I had to come to work.  Maybe this evening
they will reach full charge and the charge will further taper.

All the cells had water over the plates, some higher than others, so I now
have them all topped off.

I know that long-term sulfation is a problem.  But these batteries were
close to charged when they were abandoned more than a year ago.  So they
did not start their long abandonment discharged, but did so over time.

So any opinions on recovery?

Bob
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Re: [EVDL] Current limiting

[Bill Collins via EV]

That would be an extremely short lived event. Once current starts to flow, delta
voltage will decrease rapidly.

> On June 7, 2016 at 9:33 AM paul dove  wrote:
> 
> 
> Easy to calculate
> V=IR or I=V/R
> R should be very small in the case of connecting with wires or contactors etc.
> So if the delta voltage is 2 volts and R=0.1 ohms I=20amps.
> Easy to see that currents can get very high quickly as the delta V between
> batteries grows.
> A variable resistor could be inserted to control the current.
> In the case of my care fully charge is 149.6 volts fully empty can be as low
> as 110 volts.
> delta V = 39.6 volts  if R=0.1 ohms then I =396 amps a 500 ohm resistor drops
> that to 80mA.
> 
> 
> 
>   From: Bill Collins via EV 
>  To: ev@lists.evdl.org; ev-requ...@lists.evdl.org 
>  Sent: Tuesday, June 7, 2016 7:20 AM
>  Subject: Re: [EVDL] Current limiting
>
> The resting voltage of a lead acid battery is significantly lower than the
> voltage required to charge it. For example: a fully charged 12 volt battery
> has
> a resting voltage of 12.6, but will not draw much current unless you apply
> 13.5
> volts or so. This means that when you connect two batteries with different
> states of charge, less current flows than many people think.
> 
> Bill
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> 
> 
>
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Re: [EVDL] Current limiting

[paul dove via EV]

Easy to calculate
V=IR or I=V/R
R should be very small in the case of connecting with wires or contactors etc.
So if the delta voltage is 2 volts and R=0.1 ohms I=20amps.
Easy to see that currents can get very high quickly as the delta V between 
batteries grows.
A variable resistor could be inserted to control the current.
In the case of my care fully charge is 149.6 volts fully empty can be as low as 
110 volts.
delta V = 39.6 volts  if R=0.1 ohms then I =396 amps a 500 ohm resistor drops 
that to 80mA.



  From: Bill Collins via EV <ev@lists.evdl.org>
 To: ev@lists.evdl.org; ev-requ...@lists.evdl.org 
 Sent: Tuesday, June 7, 2016 7:20 AM
 Subject: Re: [EVDL] Current limiting
   
The resting voltage of a lead acid battery is significantly lower than the
voltage required to charge it. For example: a fully charged 12 volt battery has
a resting voltage of 12.6, but will not draw much current unless you apply 13.5
volts or so. This means that when you connect two batteries with different
states of charge, less current flows than many people think.

Bill
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Re: [EVDL] Current limiting

[Bill Collins via EV]

The resting voltage of a lead acid battery is significantly lower than the
voltage required to charge it. For example: a fully charged 12 volt battery has
a resting voltage of 12.6, but will not draw much current unless you apply 13.5
volts or so. This means that when you connect two batteries with different
states of charge, less current flows than many people think.

Bill
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[EVDL] EVLN: EV-newswire posts for 20160607

[brucedp5 via EV]

http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-81yrold-Rooney-s-enclosed-ELF-Electric-tricycle-sets-him-free-in-any-weather-td4682423.html
EVLN: 81yrold Rooney's ELF enclosed-Electric-tricycle sets him free in any
weather
For Jerry Rooney, it's always a nice day for a ride
Bike advocate Jerry Rooney takes his ELF out for a spin in his north
Corvallis neighborhood last week. The ELF stands for Electric, Light and ...

http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-Getting-around-Electric-is-the-tuk-of-the-town-td4682424.html
EVLN: Getting around Electric is 'the tuk of the town'
An electric, zero-emission version of the three-wheeled tuk-tuk is being
billed as a short-distance rival to Uber and taxis in Europe, Africa and
Asia ...

http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-INR800k-12k-M-amp-M-in-e-Verito-72V-EV-launched-r-100km-ts-86kph-td4682425.html
EVLN: INR800k/$12k M e-Verito 72V EV launched r:100km ts:86kph
Mahindra e-Verito sedan with 72V electric motor to be launched on June 2 in
India ... 
 ... its second fully electrically powered vehicle e-Verito on June 2. ...
The company claims a top speed of 86kmph and a range of 100km ... Expected
price for the e-Verito hovers around Rs. 8 lakh

http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-First-Responders-cut-open-Tesla-Model-X-EV-v-td4682426.html
EVLN: First Responders cut open Tesla Model X EV (v)
Watch a fire department slice open a Tesla Model X
Extrication experts show how first responders can access a Tesla Model X's
passengers after a crash ...




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


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[EVDL] EVLN: 1st Responders cut open Tesla Model X EV (v)

[brucedp5 via EV]

% Slow paced instructional might be more palatable at 2x speed, hidden pull
cords to open frunk & doors (?good info for thieves?), destruction starts at
14min point %

http://www.autoblog.com/2016/06/02/watch-fire-department-slice-open-model-x/
Watch a fire department slice open a Tesla Model X
Jun 2nd 2016  Danny King

[video  / Teslarati, Brook Archer/YouTubeImage Credit: Brook Archer/YouTube
https://youtu.be/D4peF1EYke8
Tesla Model X First Responder Training - Advanced Extrication
Brock Archer  May 24, 2016
The Tesla Model X may create some unique challenges for rescuers. In this
video we take a close look at Model X from a responder perspective. With
Brock Archer - Advanced Extrication and Randall Wells - Asst. Chief, Denver
Fire
More at - advancedextrication.com  Facebook -
facebook.com/advacnedextrication
]

Tesla's design tweaks, manual pull cords ease first-responder access to the
Model X.

Well, at least one conclusion can be made from a recent 22-minute tutorial
showing how first responders can get at passengers inside of a crashed Tesla
Model X: if you're going to total one, you should probably do it in Denver.
Brook Archer of Advanced Extrications and Randall Welles, assistant chief of
the Denver Fire Department, have shot an educational video showing the
step-by-step process for firefighters, paramedics, and other first
responders. Teslarati says Tesla showed off the video at the company's
shareholders conference this week. Without a doubt, the process is quite
involved.

The good news is that Tesla had been paying attention to potential safety
hazards stemming from the all-electric drivetrain and falcon-wing doors, and
moved items such as the AC/DC converter and charging controller in order to
make things safer in an accident. Beyond that, the video outlines how there
are manual pull cords releasing front-trunk ("frunk"), rear deck, and side
door latches, and goes over how a hydraulic sheer can slice off the top half
of the door and the B pillar in order to remove those fussy falcon wing
doors to get to those trapped inside.

Of course, the California-based electric-vehicle maker is hoping such
measures won't be required. Three years ago, the roof of a Model X prototype
broke a crushing machine used by the National Highway Traffic Safety
Administration (NHTSA), according to Electrek. And, more recently, Tesla
said its attempt to try to flip a Model X failed. Tesla is shooting for the
Model X to be the first SUV ever to get all top ratings in safety tests.
[© autoblog.com]




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Re: [EVDL] 12v tales

[Lee Hart via EV]

Barry Oppenheim via EV wrote:

Slightly OT, does anyone have a good way to add manual function to a HV
contactor?  It would be nice to be able to turn on the DC/DC converter
manually in case of 12V failure without having to rig a jumper.  I vaguely
remember that one of the OEM EV's had such a button in the glove
compartment for that exact situation.


The simplest way is probably to add a manual switch to turn on the 
DC/DC. Just be sure it's DC rated for your pack voltage. Perhaps the 
simplest source of high voltage DC switches are antique 120/240v DC 
household switches. These are the ones that made a loud "clack" when you 
switched them on/off.


Or, add an Anderson connector to act as a switch. Plug in a mating 
Anderson that just has a shorting jumper.

--
"IC chip performance doubles every 18 months." -- Moore's law
"The speed of software halves every 18 months." -- Gates' law
--
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Re: [EVDL] 12v tales

[Lee Hart via EV]

EVDL Administrator via EV wrote:

Is it more expensive to design semiconductors to switch 10 amps at 12 volts,
or 0.4 amps at 300 volts?  That's not a rhetorical question: I don't know.


You generally pay by the watt. Similar price to switch 12v at 100a, or 
120v at 10a, etc.



You could regulate the accessory bus.That would provide the side benefit of
allowing a range of nominal voltages for the traction battery while
standardizing accessories at, say, 100 volts.

But if you're going to do that, I guess you might as well just "regulate" it
down to the now-standard 12v.


The "accessory" outlet would still need to supply 12vdc. That's a legacy 
that we'll be stuck with for a LONG time (another century at least).


I'm mainly thinking of power for all the accessories that are built into 
the car; heater, air conditioner, lights, wipers, etc. These can be 
designed for whatever the pack voltage is.

--
"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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[EVDL] EV buyers guide App Kickstarter

[Cor van de Water via EV]

EV promotion via an EV buyers guide App
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nsider-interactive-app-for-mobile-an


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

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