EV Digest 4586
Topics covered in this issue include:
1) Re: EV utility power leveling. Re: Fwd: Opportunity power
by Lee Hart <[EMAIL PROTECTED]>
2) Re: power line leakage, was: Re: Inverters for EV to grid
connection
by Lee Hart <[EMAIL PROTECTED]>
3) Re: Correct AGM charging (was: A timer on PFC chargers)
by "Rich Rudman" <[EMAIL PROTECTED]>
4) Re: PFC-30
by "Rich Rudman" <[EMAIL PROTECTED]>
5) RE: Time for new batteries soon
by "Pestka, Dennis J" <[EMAIL PROTECTED]>
6) Re: PFC-30
by "Rich Rudman" <[EMAIL PROTECTED]>
7) Re: Powering refridgerator off of HV traction pack
by Neon John <[EMAIL PROTECTED]>
8) Re: 200VDC to 120VAC Inverter
by Neon John <[EMAIL PROTECTED]>
9) RE: Inverters for EV to grid connection
by "Noel P. Luneau" <[EMAIL PROTECTED]>
10) Re: Thoughts on friction and traction - rotating mass
by David Dymaxion <[EMAIL PROTECTED]>
11) Re: Time for new batteries soon
by "David Roden" <[EMAIL PROTECTED]>
12) Re: 200VDC to 120VAC Inverter
by Danny Miller <[EMAIL PROTECTED]>
13) Re: Time for new batteries soon
by [EMAIL PROTECTED]
14) Tracker FOR SALE
by "Mark Hanson" <[EMAIL PROTECTED]>
15) Re: PFC-30
by "Sharon Hoopes" <[EMAIL PROTECTED]>
16) Getting started with a mobility scooter
by "Michael Causey" <[EMAIL PROTECTED]>
17) Re: Time for new batteries soon
by "David Roden" <[EMAIL PROTECTED]>
18) Alternative batteries - was : RE: LA Times front page article on
EVs today
by "Michaela Merz" <[EMAIL PROTECTED]>
--- Begin Message ---
>> It would be safe to say that most people drive during the day and
>> park their cars at night. Electric rates... Higher during the day
>> and lower at night. If you follow this schedule then you will do
>> most of your charging during the overnight, low demand, lower
>> cost times.
> - Not really true as many charge their EV's as soon as they get to
> work though this is still usually a non peak time.
You'll see people promoting all sorts of EV charging methods (called
"infrastructure" by the wordmongers). The "EV charger as a gas pump"
model assumes electric gas stations, where people drive to fast-charge
their EVs, just like they refuel their ICEs. I think this is a flawed
idea, as it maximizes the need for high peak power usage right at the
time when electricity usage is already high. It also makes sure that EVs
are no more convenient to charge than ICEs. This is the model proposed
by people who DON'T want EVs to succeed.
Those who actually *do* have EVs almost invariably charge them at home
overnight. This is the most convenient way to do it. Power consumption
is low and occurs during off-peak times. The charger is the least
susceptible to vandalism or breakdown issues (broken charger when you
need it the most). It has the fewest compatibility issues (having public
chargers that are incompatible with your EV). It's the lowest cost
option because no infrastructure changes are needed.
> EV's can really help by using a batt charger as a power inverter,
> supplying electricity to the grid in times of peak power needs,
> usually between noon and 3 pm from the batt pack.
I think this is a good idea, but fatally flawed. Peak power occurs in
the late afternoon and early evening, right when you want your batteries
fully charged to drive home. If they draw power to prop up the grid,
then you won't have a full charge for the trip home. So it only works if
you have a non-standard working schedule (EV parked all day, and driven
at night).
A second problem is economics. The utility companies charge dearly for
peak power, but pay almost nothing to buy power from small producers.
But power from batteries is *very* expensive -- the cost of your 2-way
inverter/charger and the wear and tear on your batteries means it's
costing you 20 cents/kwh or more for the power they'll only pay you 2
cents/kwh for.
--
Humanity is acquiring all the right technology for all the wrong
reasons.
-- R. Buckminster Fuller
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--
Humanity is acquiring all the right technology for all the wrong
reasons.
-- R. Buckminster Fuller
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
James Massey wrote:
>> (urban legend?) someone building some sort of grid structure
>> underneath some HV power lines and powering his house from
>> the magnetic field?
> I heard this one too, but I can't remember the source.
I recall an article in the IEEE "Spectrum" magazine on what might be
this case in the 1970's. It involved a Wisconsin dairy farmer, and going
by memory it basically agreed with what James wrote. The power lines
were not operating properly, which caused the farmer's problems, and
gave him the opportunity to "steal" power. BTW this farmer was no
country bumpkin -- he was a trained electrical engineer, and knew full
well what was going on and how to design an "antenna" for his purposes.
The power company was just being stubborn and refusing to do anything
about legitimate complaints until they had their noses rubbed in it.
Regarding "cosmic energy". The sun is by far the largest source of
off-the-earth energy, drowning out all other sources by a wide margin.
Solar cells already allow us to capture a useful fraction of this
energy, and they are only bothering to tap the visible light portion of
the spectrum. The sun is actually a broadband emitter, covering the
entire electromagnetic spectrum. So it is not implausible to build other
kinds of "solar cells" that simply tap the sun's energy in other parts
of the spectrum (infrared, ultraviolet, microwaves and other portions of
the RF spectrum, etc.). It's just that our atmosphere has a handy "hole"
that passes visible light, but tends to block and reduce other
wavelengths to varying degrees.
--
Humanity is acquiring all the right technology for all the wrong
reasons.
-- R. Buckminster Fuller
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
What I can tell you ,Bill and the list, is that 2 amps No voltage limit,
after you have a Yt or any 50 or so amphour AGM bulk charged to less than 2
amps and 14.8 volts,
Will kill the string of batteries in Just about the 200 to 250 cycle limits
that are published. This holds true for string lengths greater than about 4
batteries or 48 volts.
What you are telling Newibes Bill, is a recipe for quick Death of Optima
Yellow top packs.
I don't care who Knows how much Bill, this is a Fact.
I bet there are about 100 Yt users on this list that have wasted a Yt pack
doing just what you say.
Why You wish to support a known fail mode is beyond me and dragging the
Skills of a battery pro Like Mr. Olson into this is fool hardy. For all of
us.
The hard electro chemistry is not in dispute. The implementation of it is.
If all Yts could take 2 amps and not vent, This would be a very short
factual discussion. The fact is the recombiner structure, in a number...not
all...can't cope with this level of gassing. They get vented and dried
out... Dead Yt. Yard it out.... try again. Do this about twice... and you
have a very uneven cycle life and hard to balance pack. This gets even
easier to Vent or reverse a battery.
> There isn't a lot you (or I) can tell John Olson about AGM
batteries.
Lets keep John out of this unless he wishes to clash with us on this list.
Bill I believe you and I have a very high respect for Mr. Olson and his
capabilites... Lets keep it that way.
You and I ,Bill will of course thrash this over until we find that we agree
or get tired of Beating it with a stick.
Also... I have designs on a 75Kw charger doing LeadAcid AGM charging....
There are things that I am going to know, that most don't, in a hurry.
I am all ears, but... I don't take things that I know for a fact, lightly.
So instead of thrashing each other, Why don't we stick to the basics that a
Newbie just getting into AGM for the first time should know about??
Lets help those that need help. Clearly we have different opinions and
different data sets that support our View.
You have Regs and a PFC Charger, You had Yts, and now have NiCads.
What do you recomend that a newbie do to keep his pack healthy??? Should we
get into the trials and tribulation of modular chargers??? Why they are
good idea, Why they tend to fail in bad ways.
The First step is to try to find a " Bad one "and keep it from getting in
the pack in the first place.
How would you have sombody with just a DVM and a notr book look for
weak ones?
Once assembled.. What else should you look for???
Come on Bill, lets help them do it right the first time.
The fine end of charge magic... Well lets get them fully charged first...
Since if you don't get them basicly charged.... the rest is a waste of time.
Your 3 ways to kill a AGM all being things you HAVE to do to a AGM is one
of the best summaries I have seen As to how to finish charge a AGM.
If you analyize your own dialog, it actually explains my reasoning.
Rich Rudman
Manzanita Micro
--- End Message ---
--- Begin Message ---
Not a simple question since the main hazzard of NiMh is the garrentied
thermal issues on the each end of the charge cycle.
This I have done manually recently...
If you have some form of temperature termination at the end of each charge
cycle, A PFC charger works rather well.
But I don't track temp or amphours or Kwhr with my chargers. So... you will
need to support your own end of charge determinations.
Yes I have done this... and no it was not hands off operation.
Be ware that any charger should have temp sensors for doing NiMh battery
pack work. Mine or others... This is the one major draw back to this
chemistry... Cars have caught fire becasue of this.
They were Million dollar cars with all sorts of temp sensors and state of
charge meters.... they still didn't catch it....
Be carfull!!!
Rich Rudman
Manzanita Micro
----- Original Message -----
From: "Noel P. Luneau" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Monday, August 15, 2005 6:34 PM
Subject: RE: PFC-30
> Hey Rich,
>
> Can the PFC's be adjusted for a NiMH charging profile?
>
> Thanks,
>
> Noel
>
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED] On Behalf Of Rich Rudman
> > Sent: Monday, August 15, 2005 3:22 PM
> > To: ev@listproc.sjsu.edu
> > Subject: Re: PFC-30
> >
> > You can't!
> > They are that popular.
> >
> > I can make you one though.
> >
> > Rich Rudman
> > Manzanita Micro.
> >
> > I am going to be back ordered here this week. One left on the
> > shelf, then it's going to be a couple of weeks before I can
> > get more loaded and tested.
> >
> >
> >
> > ----- Original Message -----
> > From: "Sharon Hoopes" <[EMAIL PROTECTED]>
> > To: "ev" <ev@listproc.sjsu.edu>
> > Sent: Monday, August 15, 2005 12:22 PM
> > Subject: PFC-30
> >
> >
> > > Bill hoopes < [EMAIL PROTECTED] >
> > > WHERE CAN I BUY AN used PFC-30 CHARGER???
> > >
> > > Bill & Sharon Hoopes
> > > [EMAIL PROTECTED]
> > >
> > >
> >
> >
>
> This e-mail and any attachments may contain confidential and privileged
information. If you are not the intended recipient, please notify the sender
immediately by return e-mail, delete this e-mail and destroy any copies. Any
distribution or use of this information by a person other than the intended
recipient is unauthorized and may be illegal.
>
--- End Message ---
--- Begin Message ---
Mark;
Good to see another Midwesterner doing an electric conversion.
I am struggling with the same battery decision.
The one thing I have learned is if you keep your DOD to 50% or less most of
the time, you can get 3 - 5 years out of the AGM's. John Wayland and others
have gotten decent life spans out of theirs.
Dennis
Elsberry, MO
-----Original Message-----
From: Mark Ward [mailto:[EMAIL PROTECTED]
Sent: Wednesday, August 17, 2005 6:53 AM
To: ev@listproc.sjsu.edu
Subject: Re: Time for new batteries soon
All this stuff scares me a bit and has me wondering if I am deciding right
to go with AGM batteries. I have been planning a 156v pack for my
conversion. I don't want to have to spend an extra $40-50 per battery just
for individual regulators. What scares me more is the apparently short life
span that some folks are implying on the AGMs. I need to get 2 or 3 years
out of my pack to make the investment worth while. I also want to be sure
and get a correct charger. If the agm pack is only going to last a year, I
might as well go with "cheapie" marine batteries that can be purchased for a
third of the price!
There has to be a happy medium somewhere!
Mark Ward
St. Charles, MO
www.saabrina.blogspot.com
----- Original Message -----
From: "John Westlund" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Wednesday, August 17, 2005 2:52 AM
Subject: Re: Time for new batteries soon
> >Is this about the life I can expect from these
>>batteries? Is there any logic to going to to Optimas or
>>something that can
>>handle the higher currents better? My previous pack had
>>range of about 35 miles
>>on a warm day of all freeway miles.
>
> There's plenty of logic in switching batteries. 35 miles per
> charge at 50-60 mph speeds on the freeway means you're using
> that charge in under an hour. The same weight in AGMs that
> you have in floodeds should give you better range since they
> have a lower Peukert's exponent.
>
> Further, a pack of Optima D750s that weighs the same as the
> current pack will have a hiher voltage. This would mean a
> higher top speed if your motors and controllers can be
> configured to handle the increased voltage.
>
> However, if you switch to Optimas, you will want a charger
> and regulators suited for them to maximize life. My hunch is
> that the Tropica's charger will kill a pack of Optimas or
> any sealed lead acid battery for that matter.
>
> So changing the batteries to sealed, with it necessitating a
> new charger and regs, is about a $4k upgrade or more.
>
--- End Message ---
--- Begin Message ---
Hello Bill and Sharon??
I have had two e-mails with no new dialog.
Rich Rudman
Manzanita Micro
--- End Message ---
--- Begin Message ---
That would work fine, assuming the cruise can hold the motor RPM tight
enough to maintain frequency.
Another possibility, something that should be more efficient and
eliminate the tight speed control, would be to obtain the PM
alternator and inverter from an inverter generator such as the Honda
EU series. The alternator speed would not matter then. One could
even take the throttle servo and operate the EV throttle pot to
achieve the same variable speed as with the gas generator.
Depending on the model, one might even be able to run the inverter
directly off the pack. I know that the hondas output 3 phase AC at
>100 volts at full throttle. It is immediately rectified so DC input
should work fine. One might have to dummy in a tach signal, not for
sure.
John
On Tue, 16 Aug 2005 18:33:52 +0000, Jeff Shanab
<[EMAIL PROTECTED]> wrote:
>How bad would it be to bolt an AC gen head onto the aux shaft of the
>drive motor, put the EV in neutral and set the cruise control? A lot
>quieter than the gas genny and usable for "regen" if connected to a
>charger. (lots of conversions and waste)
>
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
--- End Message ---
--- Begin Message ---
Sure. You can buy transformers already configured for that service.
They're called buck/boost transformers.
John
On Tue, 16 Aug 2005 15:27:37 -0700 (PDT), Edward Ang
<[EMAIL PROTECTED]> wrote:
>After toying around with different configurations of a
>transformer, I found some interesting stuff. But, I
>still could not quite get the physics behind it.
>
>Could we use a transformer as an AC voltage divider?
>
>Look at the 2 configurations below.
> ___________________
> | 240-36V
> -+__ __________ AC
> *) || C*
> ) || C
>240V ) || C 36V
> AC ) || C AC
> --+_) || C___
> | |
> |_________|
>
>This is the "normal" way to reduce the AC voltage as
>in an auto-transformer.
>
>But, how about this? I am essentially using the
>transformer as a voltage divider. I tested this
>configuration, and it seems to divide the voltage
>happily. But, how does it respond to different loads?
> _______________________
> | 240-36V
> | ___________________ AC
> | |
> --(---+__ ________
> | *) || C |
> | ) || C |
> |___ ) || C 36V |
> | ) || C AC |
>240V |_) || C*__ |
> AC | | |
> |_________| |
> |
> ______________________|
>
>My brain needs some time to digest this.
>
>Ed Ang
>
>--- Lee Hart <[EMAIL PROTECTED]> wrote:
>
>> Lee Hart wrote:
>> >> Yes, that can work. You might not need a
>> transformer, either.
>> >> The actual pulse width can be set to determine
>> the AC voltage
>> >> generated.
>>
>> Edward Ang wrote:
>> > Wouldn't this only give you the RMS of the voltage
>> generated,
>> > but the actual peak voltage would be a lot
>> different? This would
>> > be very bad if you connect something with an input
>> cap rated at
>> > 200V (for 110Vac) because your Vdc (or peak) might
>> be above 200V.
>>
>> I'm talking about a simple inverter that just chops
>> the DC into a square
>> wave, and uses phase control on the AC to limit the
>> RMS voltage to what
>> the load needs. For this to work, everything depends
>> on what you are
>> going to power with that inverter's AC.
>>
>> Power supplies for electronic equipment rectify the
>> AC line, and mainly
>> care about the *peak* voltage. Phase control on a
>> square wave inverter
>> is not effective with such loads. You should not
>> power such devices from
>> an inverter that just controls pulse width.
>>
>> Light bulbs, heaters, motors, transformers, and
>> other simple loads care
>> about the RMS value of the voltage, not the peak. So
>> you *can* power
>> such loads with a simple inverter that just controls
>> pulse width. For
>> example, 240vdc can be inverted into a 240vac square
>> wave, and then
>> phase controlled to become a 0v/+240v/0v/-240v
>> "modified sine wave". If
>> the total on-time is 25%, the RMS voltage is 120v,
>> and will power a 120v
>> light bulb or heater exactly the same as if it were
>> on 120vac. At 60hz,
>> this means:
>>
>> 0v from 0 - 6.25 msec
>> 240v from 6.25 - 8.33 msec
>> 0v from 8.33 - 14.58 msec
>> 240v from 14.58 - 16.67 msec
>>
>> An inductive load like a motor or transformer will
>> require a slightly
>> different ratio. The exact ratio depends on how
>> heavily loaded it is; a
>> light load it is mainly inductive and is more
>> towards 50% on-time.
>> Heavily loaded it moves toward a resistive load and
>> 25% on-time.
>>
>> Yes, the actual voltage applied to the device is
>> much higher. But
>> essentially all motors and transformers have enough
>> insulation to pass
>> UL hipot testing, which requires 1250 vac or more.
>>
>> > Actually, my goal is to get high power AC from my
>> '04
>> > Prius. I have alrealy tapped into the 201.6V pack
>> > with a pair of 10 gauge wires. The test data on
>> this
>> > site (www.priups.com) shows that the voltage would
>> > vary between about 210-230V if the battery is down
>> to
>> > 2 bars and the ICE kicks in to recharge it to 3
>> bars.
>> > If scaled properly, this voltage range would
>> produce
>> > 110-120Vac or 220-240Vac without any adjustment.
>> This
>> > is very tempting. (An EV would have a higher
>> ranges
>> > of voltage swing that might need a variac if set
>> up
>> > this way.) The idea of having an AT-PZEV 10kW
>> backup
>> > generator in the garage is pretty exciting.
>>
>> If you want to power any arbitrary load that you
>> might plug in, then you
>> need a "proper" inverter that delivers something
>> closer to a sine wave.
>> To make *any* load work, you will need a true
>> sinewave inverter.
>> --
>> "One doesn't discover new lands without consenting
>> to lose sight of the
>> shore for a very long time." -- Andre Gide
>> --
>> Lee A. Hart, 814 8th Ave N, Sartell MN 56377,
>> leeahart_at_earthlink.net
>>
>>
>
>
>
>
>____________________________________________________
>Start your day with Yahoo! - make it your home page
>http://www.yahoo.com/r/hs
>
>
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
--- End Message ---
--- Begin Message ---
Here in the US you can buy the same inverters that you have there with
the same features called Grid-tie. Outback and SMA and Xantrex all
provide this feature. In fact SMA has the new product called Sunny
Island that has a charge controller and generator starter built in.
However, in California while we can "sell" our excess power to PG&E, at
the end of the year our "credit" is zeroed out. In other words PG&E
keeps the excess power we generate and does not have to pay us. Why,
because the State let's them. We are hoping that SB1 "million solar
roofs" passes and that some of us will get paid for supplying PG&E with
free electricity.
Noel
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of djsharpe
> Sent: Tuesday, August 16, 2005 4:08 PM
> To: ev@listproc.sjsu.edu
> Subject: Inverters for EV to grid connection
>
> Here in Aus we have a number of manufactures who make what we
> call "grid interactive" inverters. These can be arranged to
> export energy when operator wants to, ie at certain times or
> when there is energy to sell from PV arrays etc. The same
> equipment will charge the battery at definable
> times/conditions. The difficulty I see is the wide range of
> battery voltages that people have. 120V nominal is an off the
> shelf unit. For 48V you could use your own manufacturers such
> as Xantrex formerly Trace etc.
> If there were to be sufficient interest Im sure any
> manufacturers would do a production run.
> David
>
>
This e-mail and any attachments may contain confidential and privileged
information. If you are not the intended recipient, please notify the sender
immediately by return e-mail, delete this e-mail and destroy any copies. Any
distribution or use of this information by a person other than the intended
recipient is unauthorized and may be illegal.
--- End Message ---
--- Begin Message ---
Whoops, mistake, I missed a 1/2 in the rotational energy term, so it
is effectively 1.5 times the mass for a solid cylinder, and 2 times
for a hollow cylinder.
--- David Dymaxion <[EMAIL PROTECTED]> wrote:
> If all the weight is concentrated at the rim:
>
> Energy of rotation = m * R^2 * w^2 = m * v^2
>
> Total energy = 1/2 m * v^2 + m * v^2 (energy of linear motion +
> rotational)
>
> So 1 part of the energy goes to linear motion, and 2 parts to
> rotational energy, so the wheel looks like 3 times the mass
> elsewhere
> on the vehicle.
>
> Similarly, if you suppose the weight is evenly distributed
> throughout
> the wheel,
>
> Total energy = 1/2 m * v^2 + 1/2 m * v^2
>
> So the wheel looks twice as heavy.
>
> Removing weight from the flywheel is even more important than the
> wheels, as it is geared weight and spinning faster than the wheels.
> This is probably where you heard the "7" number, where taking a
> pound
> off the flywheel is like taking around 7 pounds off the car (at
> least
> in low gear).
>
> As you said, this only matters while accelerating, and not during
> steady speeds.
>
> You can also do the experiment with a hollow tube and a filled
> tube,
> and race a heavy block with small, lightweight wheels. You'll be
> amazed how much faster the block is.
____________________________________________________
Start your day with Yahoo! - make it your home page
http://www.yahoo.com/r/hs
--- End Message ---
--- Begin Message ---
On 17 Aug 2005 at 2:52, John Westlund wrote:
> So changing the batteries to sealed, with it necessitating a
> new charger and regs, is about a $4k upgrade or more.
Converting to AGMs will also mean significantly increased per-mile cost for
battery replacement. That part of your operating cost will at least double,
and possibly increase much more than that.
OTOH you'll gain considerable convenience - I seem to recall that getting to
the batteries in a Tropica for maintenance is no picnic - and probably have
batteries that handle high currents with aplomb.
I can't guess whether you'll see better or worse life, because I don't know
what a "US225" battery is. No such battery is listed on the US Battery
website. Could you describe your current battery modules a little more
clearly?
The challenge would be fitting the right number of Optimas (or whatever)
into the Tropica's battery tray. Unless you want to get into changing the
controller, you'd probably want to do a "buddy pair" system, which would
require 24 batteries.
Let's see what you'd get. A 72v pack of US125s (is THIS what you have?)
will yield 9650 Wh at 150 amps (neglecting sag). A 72v pack of 24 Optima
YTs, buddy paired, will yield 5760 Wh at 150 amps (same proviso). So
although the Optimas would be "stiffer," you'd lose significant capacity and
range (about 40% loss).
If you could somehow fit 36 YTs in that tray ($$$$$$), you'd be at around
9100 Wh (estimated), only a 6% loss of range, and at an enormous financial
cost.
I think unless you get into an extensive rebuild - higher voltage pack, new
controllers, new charger - Optimas are not very practical for you.
You might instead look into AGM type golf car batteries. Again cost will be
much higher, but they MIGHT handle the high currents better. MIGHT.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Want to unsubscribe, stop the EV list mail while you're on vacation,
or switch to digest mode? See how: http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Note: mail sent to the "from" address above may not reach me. To
send me a private message, please use evdl at drmm period net.
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
--- End Message ---
--- Begin Message ---
Actually the terms buck and boost usually do not apply to transformer
circuits. Buck and boost converters usually require a different circuit
depending on whether they raise or lower the voltage.
A transformer is a step-up or step-down depending on just its turns
ratio. They are inherently isolating unless you have an autotransformer.
Isolation is a good thing, but may not essential depending on your
configuration.
Danny
Neon John wrote:
Sure. You can buy transformers already configured for that service.
They're called buck/boost transformers.
John
On Tue, 16 Aug 2005 15:27:37 -0700 (PDT), Edward Ang
<[EMAIL PROTECTED]> wrote:
After toying around with different configurations of a
transformer, I found some interesting stuff. But, I
still could not quite get the physics behind it.
Could we use a transformer as an AC voltage divider?
Look at the 2 configurations below.
___________________
| 240-36V
-+__ __________ AC
*) || C*
) || C
240V ) || C 36V
AC ) || C AC
--+_) || C___
| |
|_________|
This is the "normal" way to reduce the AC voltage as
in an auto-transformer.
But, how about this? I am essentially using the
transformer as a voltage divider. I tested this
configuration, and it seems to divide the voltage
happily. But, how does it respond to different loads?
_______________________
| 240-36V
| ___________________ AC
| |
--(---+__ ________
| *) || C |
| ) || C |
|___ ) || C 36V |
| ) || C AC |
240V |_) || C*__ |
AC | | |
|_________| |
|
______________________|
My brain needs some time to digest this.
Ed Ang
--- Lee Hart <[EMAIL PROTECTED]> wrote:
Lee Hart wrote:
Yes, that can work. You might not need a
transformer, either.
The actual pulse width can be set to determine
the AC voltage
generated.
Edward Ang wrote:
Wouldn't this only give you the RMS of the voltage
generated,
but the actual peak voltage would be a lot
different? This would
be very bad if you connect something with an input
cap rated at
200V (for 110Vac) because your Vdc (or peak) might
be above 200V.
I'm talking about a simple inverter that just chops
the DC into a square
wave, and uses phase control on the AC to limit the
RMS voltage to what
the load needs. For this to work, everything depends
on what you are
going to power with that inverter's AC.
Power supplies for electronic equipment rectify the
AC line, and mainly
care about the *peak* voltage. Phase control on a
square wave inverter
is not effective with such loads. You should not
power such devices from
an inverter that just controls pulse width.
Light bulbs, heaters, motors, transformers, and
other simple loads care
about the RMS value of the voltage, not the peak. So
you *can* power
such loads with a simple inverter that just controls
pulse width. For
example, 240vdc can be inverted into a 240vac square
wave, and then
phase controlled to become a 0v/+240v/0v/-240v
"modified sine wave". If
the total on-time is 25%, the RMS voltage is 120v,
and will power a 120v
light bulb or heater exactly the same as if it were
on 120vac. At 60hz,
this means:
0v from 0 - 6.25 msec
240v from 6.25 - 8.33 msec
0v from 8.33 - 14.58 msec
240v from 14.58 - 16.67 msec
An inductive load like a motor or transformer will
require a slightly
different ratio. The exact ratio depends on how
heavily loaded it is; a
light load it is mainly inductive and is more
towards 50% on-time.
Heavily loaded it moves toward a resistive load and
25% on-time.
Yes, the actual voltage applied to the device is
much higher. But
essentially all motors and transformers have enough
insulation to pass
UL hipot testing, which requires 1250 vac or more.
Actually, my goal is to get high power AC from my
'04
Prius. I have alrealy tapped into the 201.6V pack
with a pair of 10 gauge wires. The test data on
this
site (www.priups.com) shows that the voltage would
vary between about 210-230V if the battery is down
to
2 bars and the ICE kicks in to recharge it to 3
bars.
If scaled properly, this voltage range would
produce
110-120Vac or 220-240Vac without any adjustment.
This
is very tempting. (An EV would have a higher
ranges
of voltage swing that might need a variac if set
up
this way.) The idea of having an AT-PZEV 10kW
backup
generator in the garage is pretty exciting.
If you want to power any arbitrary load that you
might plug in, then you
need a "proper" inverter that delivers something
closer to a sine wave.
To make *any* load work, you will need a true
sinewave inverter.
--
"One doesn't discover new lands without consenting
to lose sight of the
shore for a very long time." -- Andre Gide
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377,
leeahart_at_earthlink.net
____________________________________________________
Start your day with Yahoo! - make it your home page
http://www.yahoo.com/r/hs
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
--- End Message ---
--- Begin Message ---
David,
Yep I'm intended to say US125s. Sorry. I'm coming to the same conclusion
although perhaps
US145s might be a good choice. A bit more lead in the same package. Hmm, the
batteries are
3lbs heavier and I have 12 so if I go on a diet an loose 36lbs it's a win win ;)
I've been wondering if the life that I got is reasonable. I just found a chart
on the US Battery
web site that talks about cycles vs depth of charge. I've been using about 45%
to get to work,
charge and then go home and charge. According to the chart I should be at about
1200 cycles.
Divide that by 2 (cycles / day) and I get 600 so I guess a year and a half is
about expected.
Steve
-----Original Message-----
From: David Roden <[EMAIL PROTECTED]>
To: ev@listproc.sjsu.edu
Sent: Wed, 17 Aug 2005 14:31:58 -0400
Subject: Re: Time for new batteries soon
On 17 Aug 2005 at 2:52, John Westlund wrote:
> So changing the batteries to sealed, with it necessitating a
> new charger and regs, is about a $4k upgrade or more.
Converting to AGMs will also mean significantly increased per-mile cost for
battery replacement. That part of your operating cost will at least double,
and possibly increase much more than that.
OTOH you'll gain considerable convenience - I seem to recall that getting to
the batteries in a Tropica for maintenance is no picnic - and probably have
batteries that handle high currents with aplomb.
I can't guess whether you'll see better or worse life, because I don't know
what a "US225" battery is. No such battery is listed on the US Battery
website. Could you describe your current battery modules a little more
clearly?
The challenge would be fitting the right number of Optimas (or whatever)
into the Tropica's battery tray. Unless you want to get into changing the
controller, you'd probably want to do a "buddy pair" system, which would
require 24 batteries.
Let's see what you'd get. A 72v pack of US125s (is THIS what you have?)
will yield 9650 Wh at 150 amps (neglecting sag). A 72v pack of 24 Optima
YTs, buddy paired, will yield 5760 Wh at 150 amps (same proviso). So
although the Optimas would be "stiffer," you'd lose significant capacity and
range (about 40% loss).
If you could somehow fit 36 YTs in that tray ($$$$$$), you'd be at around
9100 Wh (estimated), only a 6% loss of range, and at an enormous financial
cost.
I think unless you get into an extensive rebuild - higher voltage pack, new
controllers, new charger - Optimas are not very practical for you.
You might instead look into AGM type golf car batteries. Again cost will be
much higher, but they MIGHT handle the high currents better. MIGHT.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Want to unsubscribe, stop the EV list mail while you're on vacation,
or switch to digest mode? See how: http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Note: mail sent to the "from" address above may not reach me. To
send me a private message, please use evdl at drmm period net.
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
--- End Message ---
--- Begin Message ---
Hi ,
It's on www.evalbum.com under classified and then electric cars. It's
garage kept, converted in 2000, has 22k electric miles on it and all the
batteries underneath with 1/4" aluminum plate inspection hatches. 120V, 20
6V batts replaced in Feb 05'. Battery scanner, displays all 20 battery
voltages together on same VTF display.. Aux fast charger, cuts time in 1/2.
Both chargers on & off-board are iso-pfc 1800W each. Has 1000amp speed
control (with animal diversion) with safety contactors, engage and full-on.
3" body lift kit with fender flares and solid anti sway bars from
www.calmini.com . Steering stabalizer, stiffer shocks and helper springs
added. Larger 10" diameter brakes added from dealer in June 05'. Full
schematics included. I'm selling since I'm thinking of doing another EV.
65mph at 30 miles per charge, less if cold but charger pre-heats batts below
50F batt temp. (I keep in an unheated attached garage near Roanoke, VA)
EVCOM, (EV computer) displays in window/dash interface volts, amps, KWh
used, %charge left, batt controller & motor temp. LED lights, turn, stop,
running. With extra tow bar. LRR Goodyear Invicta tires and 4 spares.
Full size LRR spare on back. KTA vacuum power brakes & heater. If you want
additional photos of batts, electronics, I can email from home:
[EMAIL PROTECTED] or also view on www.solectrol.com
Mark E. Hanson
184 Vista Lane
Fincastle, VA 24090
540-563-2000x290-W
540-473-1248-H
> I looked but did not see it.
>
> Joe Smalley
> Rural Kitsap County WA
> Fiesta 48 volts
> NEDRA 48 volt street conversion record holder
> [EMAIL PROTECTED]
>
>>
> > My E-jeep (Geo Tracker) is also for sale on www.evalbum.com in
classified
> > electric cars. Mark
> > ----- Original Message -----
--- End Message ---
--- Begin Message ---
Hi Rich: I have 2 EV's Porsche 132v 105's X 22 Bat. & the festiva 72v 12X
145's.bat.
Can I charger 'input' off 120vac 15amps for the festiva???
Thanks........Bill that's is all I ask???
Bill & Sharon Hoopes
[EMAIL PROTECTED]
> [Original Message]
> From: Rich Rudman <[EMAIL PROTECTED]>
> To: <ev@listproc.sjsu.edu>
> Date: 8/17/2005 10:54:44 AM
> Subject: Re: PFC-30
>
> Hello Bill and Sharon??
>
> I have had two e-mails with no new dialog.
>
> Rich Rudman
> Manzanita Micro
--- End Message ---
--- Begin Message ---
Greetings,
I have a Pacesaver 3-wheeled mobility scooter that is 5+ years old that
belonged to my mother until she got a Jazzy wheel chair. Since I have
not really "needed" it, I do not ride it all that often. Lately, when I
do ride it, I notice that it tends to run in a kind of sputtering
fashion. That is, it goes along just fine and then all of a sudden it
seems to freeze up and stop. Sometimes it then restarts and sometimes it
does not. Not being knowledgeable about electric motors I, decided to
try and research what causes this problem and try to remedy it. Any help
would be appreciated.
Along the same line, in researching for the aforementioned problem, I
began to think about what it might take to pep it up the scooter a bit.
Any ideas?
Mike Causey
--- End Message ---
--- Begin Message ---
On 17 Aug 2005 at 14:45, [EMAIL PROTECTED] wrote:
> divide that by 2
> (cycles / day) and I get 600 so I guess a year and a half is about expected.
I would have said about 2 years, assuming you work 5 days a week. If your
battery tray makes them hot in the summer you'll see some reduced life from
that.
At 2 cycles per day, a year and a half is really not that bad. Mark Hanson
recently mentioned that he's been changing out the battery in his Tracker
yearly, which seems like a lot.
Going to US-145s will allow you to maintain a lower DOD, so perhaps buy
longer cycle life. But they cost appreciably more than 125s, so your cost
per mile would probably end up a little higher rather than lower. Also, I
think the 145s are a fraction of an inch taller, so make sure you have the
clearance.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Want to unsubscribe, stop the EV list mail while you're on vacation,
or switch to digest mode? See how: http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Note: mail sent to the "from" address above may not reach me. To
send me a private message, please use evdl at drmm period net.
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
--- End Message ---
--- Begin Message ---
Hello nerds :)
In order to make EVs more appealing to the Joe-everybodies, we need more
range. That means better batteries. What is the chance that some of the
people here start a kind of co-op to be able to handle (charge, thermal
handling) and to order i.e. lithium batteries from Saft, Valence or
Thundersky in numbers?
mm.
> Neon John wrote:
>
>> Damn, I hate that kind of article. It perpetuates the myth that all
>> EV drivers are eco-fruitcakes. It un-does all the work us un-True
>> Believers do to disassociate EVs and ourselves from the fruitcakes.
>> I'm still waiting, in vane, it appears, for an article that shows
>> Joe-everybodies driving EVs because they're fun and because they're
>> cheap and convenient to operate.
>
> Once again John has tried as hard as he could to anger his audience here
> without quite getting himself kicked off. (Not sure what that's about,
> not
> sure I want to know.) He does raise an interesting point, though it's one
> I
> think he doesn't get.
>
> "Mainstream" is a point of arrival. Meaning from somewhere else, meaning
> change is involved. Joe-everybody does not initiate change, he typically
> resists it. Let's look at some larger societal changes as an
> illustration.
>
> If it was left up to Joe-everybody, Jim Crowe would still be thriving in
> the
> south, women wouldn't be allowed to vote and they would hold only menial
> jobs if they had jobs at all. Joe-everybody doesn't care that the status
> quo makes no sense, so he won't rise up to make changes.
>
> It takes activists, people who will shake things up. Like bra-burning
> bitches (sorry, women behaving in an "un-ladylike" manner), charismatic
> ministers and fist-waving Black Panthers. Sometimes these activists are
> not
> what "mainstream" society would call model citizens. That's the point -
> to
> smack society around enough that they'll finally see the light. A sad
> commentary on us, but true nonetheless.
>
> And it takes time. It was only a few years ago that black women wearing
> their hair in corn rows at the office was considered outrageous.
> Jane-everybody doesn't do corn rows. Jane-everybody does what she's told.
> The status quo is very comforting to most people, even concerning things
> as
> mundane as their cars. Change = uncertainty = bad.
>
> In the world of EVs the opposition is more commercial than societal. But
> those commercial industries are extremely powerful. At the very least EVs
> are seen as an unpredictable new type of product. (Remember, uncertainty
> =
> bad.) At worst EVs might mean dramatically reduced profits. (I think
> that's actually true for the oil industry, since the technology exists
> today
> to cut our total national consumption by probably a third, maybe a half.
> That's why they're pushing hydrogen - it makes no sense in energy terms,
> but
> it allows them to keep selling product. I think EVs can still be
> profitable
> for the auto industry, since high-tech prestige still sells. But it's a
> new
> kind of high-tech, and new = uncertain = bad.) Those captains of industry
> are required by law to maximize profits, so that's exactly what they're
> doing - at the expense of society at large.
>
> So John, if those horrible granola-crunching tree huggers and
> bleeding-heart
> celebrities are the people you love to hate, and it gets your knickers all
> twisted up to see them getting press, you've missed the point. They're
> getting press. Joe-everybody is not. If you want to see people who meet
> your high standards get some coverage as well, how are you going to go
> about
> doing that?
>
> I'm sure NEDRA would love it if you started a new chapter for them. You
> could replace your cartoonish cheese-wedge CitiCar with a RAV-4EV and use
> it
> for deliveries from your restaurant and general normal-car-type duties.
> (What? An EV used as a normal car?) Then call your local paper and TV
> station to see if you can get some coverage more to your liking. Or you
> can
> complain about the "fruitcakes". Which is more effective?
>
> Chris
>
--- End Message ---
