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Discussion Starter #1
I am looking at getting some batteries that will make my 28 mile commute. I have a prestolite MTC4001, and a curtis 1231C, in the old style bug. I would like to run between 120 v and 144 v, because of the DC-DC I have. I would like to have some battery recommendations. I have heard the suggestion that T-105 would be good, but that might be getting a bit on the heavy side for my car. I think that I could fit 1200 lbs of batteries. I at one point considered 30 XHS, but saw on the evalbum, someone had a bad experience. Does anyone else have any experience? I have heard that some have bad experience with the 8V batteries, but others like it.

My requirements: 28 mile commute consistent for the next 4 months. After that, it will be no more than 10 miles. But occasionally I would still like to be able to drive the 30 miles or so.

What are good batteries to use. And if you know of good prices, I would appreciate that as well.

Thanks,
Brian
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Discussion Starter #2
Hi,
Don't know if your 28 mi. commute is in warm, or
cold weather, or both. I'm running 144V of US Battery
8V, and they would definitely take you the distance,
no matter what the weather. Whether the bug could
handle the weight... that's another matter.
Best of luck with your decision.
Sincerely,

--- "[email protected]" <[email protected]> wrote:

> I am looking at getting some batteries that will
> make my 28 mile commute. I have a prestolite
> MTC4001, and a curtis 1231C, in the old style bug.
> I would like to run between 120 v and 144 v, because
> of the DC-DC I have. I would like to have some
> battery recommendations. I have heard the
> suggestion that T-105 would be good, but that might
> be getting a bit on the heavy side for my car. I
> think that I could fit 1200 lbs of batteries. I at
> one point considered 30 XHS, but saw on the evalbum,
> someone had a bad experience. Does anyone else have
> any experience? I have heard that some have bad
> experience with the 8V batteries, but others like
> it.
>
> My requirements: 28 mile commute consistent for the
> next 4 months. After that, it will be no more than
> 10 miles. But occasionally I would still like to be
> able to drive the 30 miles or so.
>
> What are good batteries to use. And if you know of
> good prices, I would appreciate that as well.
>
> Thanks,
> Brian
> ---- Msg sent via @=WebMail -
> http://webmail.usu.edu/
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
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Discussion Starter #3
Let say a set of batteries in your rig uses about 2 AH per mile, so to go 28
miles, this would required a minimum of 56 AH battery if you want to
discharge it down to 100% DOD which is not good. It is best to keep at or
above 50% DOD, so this now makes the battery AH at 112 AH.

But, a EV is not normally driven at the 20 hour AH rate, meaning a 220 AH
battery would have to be discharge at no more then 11 amps per hour for 20
hours.

The T-105 battery is rated for 225 AH, and at 75 amps it has a reserved
capacity of 115 minutes. The more amps you draw from the battery, the
amount of reserved minutes is reduce, thus the AH becomes:

115 mins / 60 = 1.9 hrs

1.9 hrs x 75 amps = 142 AH

Discharging this type of battery to 50% DOD is about 71 AH.

A EV using 2 AH per mile, will be about a 35 miles range.

To get 2 AH per mile, you would have to drive non-stop, not stopping and
acceleration at each light, no hill climbing or grades and stay under 75
battery amps.

But normally you may be as high as 4 AH per mile at times, so lets say the
average is about 3 AH per mile. Then your range may be 71/3= 24 miles at
50% D0D or average of (35+24)/2 = 29 miles. Looks like you will just make
it with a 225 AH battery.

Roland




----- Original Message -----
From: <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Thursday, August 16, 2007 7:00 AM
Subject: [EVDL] battery help


> I am looking at getting some batteries that will make my 28 mile commute.
> I have a prestolite MTC4001, and a curtis 1231C, in the old style bug. I
> would like to run between 120 v and 144 v, because of the DC-DC I have. I
> would like to have some battery recommendations. I have heard the
> suggestion that T-105 would be good, but that might be getting a bit on
> the heavy side for my car. I think that I could fit 1200 lbs of
> batteries. I at one point considered 30 XHS, but saw on the evalbum,
> someone had a bad experience. Does anyone else have any experience? I
> have heard that some have bad experience with the 8V batteries, but others
> like it.
>
> My requirements: 28 mile commute consistent for the next 4 months. After
> that, it will be no more than 10 miles. But occasionally I would still
> like to be able to drive the 30 miles or so.
>
> What are good batteries to use. And if you know of good prices, I would
> appreciate that as well.
>
> Thanks,
> Brian
> ---- Msg sent via @=WebMail - http://webmail.usu.edu/
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Discussion Starter #4
[email protected] wrote:
> I am looking at getting some batteries that will make my 28 mile
> commute... Prestolite MTC4001, Curtis 1231C, in the old style bug...
> 120-144v... I would like to have some battery recommendations.

You've had lots of good comments so far. I can add a few.

6v golf cart batteries would be great. They can easily meet your range
requirements. They last a long time, and will give you the lowest cost
per mile. But they are pretty heavy for a bug; 120-144v worth is
1200-1600 lbs.

8v golf cart batteries should also work well. The range would be less,
but with care can still make your commute (avoid fast acceleration and
high speed driving). Cost per mile will be a little higher; they cost
less initially, but more than make up for it with shorter life. They
will be lighter, at 1000-1200 lbs.

12v batteries like the 30XHS would be a poor choice. Life will be very
short, and it's unlikely they would give you the range you seek unless
you drive very slow and conservatively.

The Curtis 1231 is easily capable of drawing enough battery current to
shorten the life of your batteries. I'd suggest turning its current
limit pot (on the side of the case behind the screw) all the way down to
keep yourself from inadvertently ruining the batteries by overdoing it.
--
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Discussion Starter #5
On 16 Aug 2007 at 7:00, [email protected] wrote:

> I am looking [for] batteries that will make my 28 mile commute.

Is that 28mi one way, or round-trip?

Can you charge at work? If yes, it'll be MUCH easier.

David Roden - Akron, Ohio, USA
EVDL Administrator

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Discussion Starter #7
It is 28 miles round trip. I should be able to charge at the halfway point as well.

What is your suggestion on batteries?

Brian


On Thu Aug 16 9:54 , David Roden <[email protected]> sent:

>On 16 Aug 2007 at 7:00, [email protected] wrote:
>
>> I am looking [for] batteries that will make my 28 mile commute.
>
>Is that 28mi one way, or round-trip?
>
>Can you charge at work? If yes, it'll be MUCH easier.
>
>David Roden - Akron, Ohio, USA
>EVDL Administrator
>
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>EVDL Information: http://www.evdl.org/help/
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>Note: mail sent to "evpost" or "etpost" addresses will not
>reach me. To send a private message, please obtain my
>email address from the webpage http://www.evdl.org/help/ .
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>
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Discussion Starter #8
On 16 Aug 2007 at 10:29, [email protected] wrote:

> It is 28 miles round trip. I should be able to charge at the halfway point as
> well.
>
> What is your suggestion on batteries?

If you can get one-third of the vehicle weight in golf car batteries, you'll
have a practical 40 mile range at moderate spees. This should be plenty to
handle your commute even if you can't charge during the day.

Voltage is unimportant for range. If your empty glider weighs, say, 1600
lb, figure 800-900 lb of lead. That's 12 to 14 golf car batteries. Then,
in an ideal world, you'd choose your controller and motor to operate on 72 -
84 volts and produce around 40kW to provide adequate acceleration
performance. With a DC series motor, this would mean a 500 to 600 amp
controller.

Since you already have the controller and motor, your choices are more
limited. I think 72v is too low for a 1231C. You might consider using 15 8-
volt golf car batteries. They're a decent compromise between 6v life and
12v voltage. Don't draw more than 375 amps from them if you can help it.
This would be 45kW, which should be more than enough for 1960s VW Bug
performance.

David Roden - Akron, Ohio, USA
EVDL Administrator

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Discussion Starter #9
Hi David et al.,

I have a question about your statement that voltage is unimportant for
range. I realize that providing current determines range (as long as
you can provide X amps, you can keep going) and that voltage equates to
speed. However, doesn't adding additional series batteries (like going
from say, 96V to 108V) add capacity and thus increase range? Since you
have more batteries/lead, don't they provide more capacity and hence
more range? It is certainly easier for 18 6volt golf cart batteries to
provide, say, 200 amps than it is for 16 6volt batteries. I've heard
folks argue that adding batteries won't give extra range, so I thought
I'd ask for clarification.

tnx,
john

David Roden wrote:
> Voltage is unimportant for range.

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Discussion Starter #12
> I realize that providing current determines range

Not quite. Current gives you torque and torque provides acceleration.

> voltage equates to speed

It depends on the situation. Sometimes this happens. Not always. Voltage
is not the only factor influencing top speed. A motor and controller system
can be designed to give you almost any top speed from almost any voltage.
That's why I say the best way to design an EV is to start by determing what
battery will serve your needs, then design the rest of the drive system to
work with the battery.

> Since you have more batteries/lead, don't they provide more
> capacity and hence more range?

Again, there are various factors in play. But in general, lead is your
fuel; more of it gives you more range. You can get more lead by using more
batteries. You can also get more lead by using fewer batteries, but larger
ones.

Someone mentioned amp-hours as proportional to range. This isn't quite
right either, unless voltage is held constant. Range is influenced by Watt-
hours of energy storage.

David Roden - Akron, Ohio, USA
EVDL Administrator

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Discussion Starter #13
Like David said range is by wh

Analogy is
gals * miles/gal = miles range
usable kwh / (wh/mile) = miles range (some people use miles/wh just
to make the analogy stronger)

My ev gets an awful 400ish wh/mile
I have 24 orbitals that are 36ah at 1 hr rate
24*12*36=10kwh *.8=8.3kwh/400(wh/m) = 21 miles (the .8 is never take
lead below 20%soc)

That is a maximum on a new pack and at 16 miles the voltage sag is too
much for my liking. I think part of the reason my first pack got
murdered was that I use my power in 1/2 hour. The batteries are more
probably more like 24ah; which works out to 17 miles. After I switched
jobs where i was no longer topping off at work and the weather turned
cold the 12 miles I was driving dipped below the 20%soc.

I know the mileage(wh/mile) is dismal. but at least 3 people in the last
month from work, who drive similar route, have commented on the fact
that the EV is not slow. They all seem surprised. (just wait until i get
the lifepo4 pack!)



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Discussion Starter #14
Thanks David and all,

I was really just looking for confirmation that adding two additional
batteries to the voltsrabbit design would boost the range. Of course, I
should know that I really need to be correct and explicit in my
terminology when I ask questions here.

Thanks again,
John

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Discussion Starter #17
Joseph,

You've been working too hard this summer. Adding batteries and leaving everything else the same will always add range. In fact in the case of lead acid batteries the range can be determined almost exclusively by how much weight in batteries you are carrying. Whether they are in series or parallel makes very little difference.

BTW - I should be down at the track watching the Nedra guys run right now, but it's looking like a possible rain out tonight. I called Wayland about a half hour ago and they had cars lined up on the track trying to keep it dry hoping the rain will pass.

damon> Wait a minute, guys - as has been stated before, adding batteries will NOT > necessarily give you more range! It will give you somewhat better > performance, all else being equal. The amp-hours remains the same for any > number of batteries connected in series, and the additional weight will > negate most of the benefit beyond a certain point.> > Batteries connected in parallel will give more range, batteries connected in > series will boost performance.> > Joseph H. Strubhar>
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Discussion Starter #19
Correct,

Adding batteries will always increase the amount of
energy that you are carrying and it is the energy that
gives you range.
You can easily see that from the reasoning that Joe used:
Adding batteries in series will not give more Ah, so he
drew the (false) conclusion that the range will not
increase when the Ah stay the same and only the voltage
increases. But if you look at how a controller works then
you see that the controller will perform a task called
"current multiplication" when the output voltage is
lower than the input voltage, (almost) equal to the
rate between the two.
Eaxmple: 120V and 100A input from the battery pack can
result in 60V and (almost) 200A output into the motor,
to maintain a certain driving speed.
Both are (almost) the same amount of power: 12kW.
Now if two batteries are added to the pack, the same
power is delivered at 144V when the batteries deliver
approx 80A.
This means that each battery delivers less power and
this means that it can deliver the required power for
a longer period, because the total energy contained
in the pack is increased by adding batteries.

Hope this clarifies,

Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
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-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of damon henry
Sent: Saturday, August 18, 2007 8:19 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] battery help


Joseph,

You've been working too hard this summer. Adding batteries and leaving everything else the same will always add range. In fact in the case of lead acid batteries the range can be determined almost exclusively by how much weight in batteries you are carrying. Whether they are in series or parallel makes very little difference.

BTW - I should be down at the track watching the Nedra guys run right now, but it's looking like a possible rain out tonight. I called Wayland about a half hour ago and they had cars lined up on the track trying to keep it dry hoping the rain will pass.

damon> Wait a minute, guys - as has been stated before, adding batteries
damon> will NOT > necessarily give you more range! It will give you
damon> somewhat better > performance, all else being equal. The
damon> amp-hours remains the same for any > number of batteries
damon> connected in series, and the additional weight will > negate most
damon> of the benefit beyond a certain point.> > Batteries connected in
damon> parallel will give more range, batteries connected in > series
damon> will boost performance.> > Joseph H. Strubhar>
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