# Re: [EVDL] New EV Batteries 6v vs 12v



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

Do you know any of the reasons why 12v cells are discouraged? I know that
the overall lifespan of the pack is reduced if I go with 12V vs 6V 
but I was hoping that by going with a reputable 12V (the Trojan) that I
might be able to get a pretty reliable pack.
At 12v x 12 I'm hoping to get over 50+ miles and >55mph

I'm going to add coil overs, upgrade the torsion bar to 27mm, and going disk
brakes also. My biggest concern is adding weigh to the front of the
vehicle. If the front gets too heavy, the vehicle may become very hard to
steer, plus I don't think the front end can take too much added weight
without failing.



-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Jon Glauser
Sent: Tuesday, June 10, 2008 1:26 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] New EV Batteries 6v vs 12v

I'm working out a similar conversion (bug, 1231C, flooded). I'm likely going
to end up with 72 to 96 volts of T-145, maybe T-125 if the range is still
acceptable. This adds 900 to 1200 lbs of weight, which will put the VW close
to (or just over) its GVW. I have planned on adding coil over shocks all
around and upgrading the front brakes to disk.

I'd love to get up to 120 or 144V, but that is a lot of weight and money if
sticking with 6V batteries. Recently the list has severely discouraged using
12V batteries for various reasons.

-- 
-Jon Glauser
http://jonglauser.blogspot.com
http://www.evalbum.com/555
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## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

I think 12V batteries are discouraged because they have a lower capacity
than 6V batteries. I noticed that the 6V batteries are almost the same
physical size as the 12V ones. This means they fit more plates in the same
space. So they must be thinner/smaller. This means lower current capability.
Everybody likes the 6V batteries because you can pull 200-400A from them
occasionally and they dont care. I believe the argument is that the 12V
batteries die sooner. I would hypothosize that they die sooner because they
are being treated the same as the 6V batteries.

I think the 12V batteries can be used. Look at the total pack power in kW.
Make it lower voltage and you need higher current. Make it higher voltage
and make sure not to draw too much current (easy to do since you have so
much more voltage). But I'm not a battery expert, I'm just guessing 

-- 
-Jon Glauser
http://jonglauser.blogspot.com
http://www.evalbum.com/555
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## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*



> Jon Glauser wrote:
> 
> > I think 12V batteries are discouraged because they have a
> > lower capacity than 6V batteries.
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*



> Jon Glauser wrote:
> > I think 12V batteries are discouraged because they have a lower capacity
> > than 6V batteries. I noticed that the 6V batteries are almost the same
> > physical size as the 12V ones. This means they fit more plates in the same
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

I know Dr. Larry Tillman used 12v 120 AH Walmart pairs (in parallel), and
then 7 of those pairs for an 84v pack that got a few years of use and about
45mi range in a Geo Metro. (check out that discussion by doing a search on
google for:
Dr. Larry EV




> Higgins wrote:
> >
> > I am ready to pick batteries for my EV conversion (I have an FB-4001A
> > motor, curtis 1231C Controller)
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

LOL 50+ miles

EVERYONE who I have heard from that used 12V batteries, even Trojans, has
been extremely disappointed with how short their life was. Typically less
than 1 year.

range equals weight in batteries. Roughly speaking, for a given vehicle,
it takes 700 lbs of batteries to go as far as 1 gallon of gas.

The old air cooled bugs got about 25 mpg, so to get 50+ miles is going to
require 1400+ lbs of lead.

20 x Trojan T-105s might do it (1260 lbs). Hey, the 700lb = 1Gal is a rule
of thumb, it's not perfect.

12 x T-1275s will not cut it, they only weigh 984 lbs, maybe 30-35 mile
range. And that's MAX range. If you drive max range every day, you'll be
replacing the batteries in less than 6 months.

12 x J185H might do it, but that's a big ass battery, 122lbs, I'm not sure
I'd want to wrestle 12 of those into place.

> Do you know any of the reasons why 12v cells are discouraged? I know that
> the overall lifespan of the pack is reduced if I go with 12V vs 6V
> but I was hoping that by going with a reputable 12V (the Trojan) that I
> might be able to get a pretty reliable pack.
> At 12v x 12 I'm hoping to get over 50+ miles and >55mph
>
> I'm going to add coil overs, upgrade the torsion bar to 27mm, and going
> disk
> brakes also. My biggest concern is adding weigh to the front of the
> vehicle. If the front gets too heavy, the vehicle may become very hard to
> steer, plus I don't think the front end can take too much added weight
> without failing.
>
>
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On
> Behalf
> Of Jon Glauser
> Sent: Tuesday, June 10, 2008 1:26 PM
> To: Electric Vehicle Discussion List
> Subject: Re: [EVDL] New EV Batteries 6v vs 12v
>
> I'm working out a similar conversion (bug, 1231C, flooded). I'm likely
> going
> to end up with 72 to 96 volts of T-145, maybe T-125 if the range is still
> acceptable. This adds 900 to 1200 lbs of weight, which will put the VW
> close
> to (or just over) its GVW. I have planned on adding coil over shocks all
> around and upgrading the front brakes to disk.
>
> I'd love to get up to 120 or 144V, but that is a lot of weight and money
> if
> sticking with 6V batteries. Recently the list has severely discouraged
> using
> 12V batteries for various reasons.
>
> --
> -Jon Glauser
> http://jonglauser.blogspot.com
> http://www.evalbum.com/555
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

That's pretty much it. People normally select 12V batteries because they
want a lighter pack. So instead of 20 x 6V they buy 10 x 12V. Then they
drive it like it's the same. They pull the same amps and try to drive the
same distance.

Since the 12V batteries typically have fewer/smaller plates, they can
safely handle LESS current. We are talking 100-200 amps instead of
200-400 amps.
Since they weigh less they have less range.
People using 12V batts tend to push the range, instead of 50% DoD they go
80-90% DoD sometimes 100%.

With 50% Depth of Discharge you might get 1,000 to 2,000 cycles. With 80%
you'd be lucky to get 200-300 cycles.
Add to that the higher (relative) discharge currents and you can end up
warping the plates and/or reversing cells. This leads to early death.

You could possibly get good life out of 12V batts if you drove/accelerated
slowly (let the blue haired ladies pass you) and kept your range short,
maybe 10-15 miles.

Of course my opinion is, if you're only going to go 10 miles, ride a bike.


> I think 12V batteries are discouraged because they have a lower capacity
> than 6V batteries. I noticed that the 6V batteries are almost the same
> physical size as the 12V ones. This means they fit more plates in the same
> space. So they must be thinner/smaller. This means lower current
> capability.
> Everybody likes the 6V batteries because you can pull 200-400A from them
> occasionally and they dont care. I believe the argument is that the 12V
> batteries die sooner. I would hypothosize that they die sooner because
> they
> are being treated the same as the 6V batteries.
>
> I think the 12V batteries can be used. Look at the total pack power in kW.
> Make it lower voltage and you need higher current. Make it higher voltage
> and make sure not to draw too much current (easy to do since you have so
> much more voltage). But I'm not a battery expert, I'm just guessing 
>
> --
> -Jon Glauser
> http://jonglauser.blogspot.com
> http://www.evalbum.com/555
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


_______________________________________________
For subscription options, see
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----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

Folks seem to be finding that 8v batteries give a good compromise. At
least they are real deep cycle batteries.



> Dan Maker <[email protected]> wrote:
> > On 6/10/08, Peter VanDerWal <[email protected]> wrote:
> >> That's pretty much it. People normally select 12V batteries because they
> >> want a lighter pack. So instead of 20 x 6V they buy 10 x 12V. Then they
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

I have owned both bugs and bus's it seems like the front beam assemblies 
are very similar I have never tried to mount a bus unit on a bug but if 
possible you would gain bigger brakes and I be leave 3/4 ton carrying 
capacity on most bus's there were even some 1 ton trucks /pickups made, Is 
there a VW guru on list to ask if its a possible up grade? Gary Foster
----- Original Message ----- 
From: "Higgins" <[email protected]>
To: <[email protected]>
Sent: Tuesday, June 10, 2008 1:54 PM
Subject: [EVDL] New EV Batteries 6v vs 12v


>
> I am ready to pick batteries for my EV conversion (I have an FB-4001A 
> motor,
> curtis 1231C Controller)
> I have decided to go with Flooded batteries, but Im having difficulty
> understanding how best to choose between a T125 (6v) pack or a T1275 
> (12v)
> pack. (Ie the relationship between top speed, distance, voltage, and AH)
>
> I can probably get 11-12 of the 12V batteries for 144v, and maybe a few 
> more
> if I go 6V (maybe up to 17). Cost and overall weight are my concerns, as
> my vehicle is an old VW, and the front end suspension wasnt built to take 
> a
> lot of weight up front. Any advice or calculation methods would be
> helpful!
>
>
> -- 
> View this message in context: 
> http://www.nabble.com/New-EV-Batteries-6v-vs-12v-tp17714128p17714128.html
> Sent from the Electric Vehicle Discussion List mailing list archive at 
> Nabble.com.
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev 

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

If you have a low weight car like a Geo, and pair them up to share the
current, and only take the voltage up to like 72 or 84v, then you CAN get 40
mile range and several years of use. (see my message below, or do a search
on google for: Dr. Larry EV




> RedBeard wrote:
> >
> > On 6/10/08, Peter VanDerWal <[email protected]> wrote:
> >> That's pretty much it. People normally select 12V batteries because they
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

What would be the advantage of paired 12Vs vs a single string of 6V
batteries?
The 12Vs would cost more and weigh about the same...

>
> If you have a low weight car like a Geo, and pair them up to share the
> current, and only take the voltage up to like 72 or 84v, then you CAN get
> 40
> mile range and several years of use. (see my message below, or do a
> search
> on google for: Dr. Larry EV
>
>


> > RedBeard wrote:
> >>
> >> On 6/10/08, Peter VanDerWal <[email protected]> wrote:
> >>> That's pretty much it. People normally select 12V batteries because
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

Good question. It's $144 per pair of 120 AH Costco batteries. How much is
it for 2 6v 240 ah batteries (to get you the 12 volts) They seem to be
really expensive. Maybe I'm just looking in the wrong place.




> Peter VanDerWal wrote:
> >
> > What would be the advantage of paired 12Vs vs a single string of 6V
> > batteries?
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

I understand Sam's Club sells 6v GC batts for $67

If you want to compare the price of Trojan T-105, then it aught to be
compared to Trojan 12V batteries.

I mean, if you're going to compare the prices for generic batteries, then
both sides should be generic.

>
> Good question. It's $144 per pair of 120 AH Costco batteries. How much
> is
> it for 2 6v 240 ah batteries (to get you the 12 volts) They seem to be
> really expensive. Maybe I'm just looking in the wrong place.
>
>


> > Peter VanDerWal wrote:
> >>
> >> What would be the advantage of paired 12Vs vs a single string of 6V
> >> batteries?
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*



> Higgins wrote:
> >
> > I am ready to pick batteries for my EV conversion (I have an FB-4001A
> > motor, curtis 1231C Controller)
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

> So from all the postings on this thread, I am going to assume that if I go
> with the 12 x 12v batteries I should just keep an eye on my driving and
> try to minimize current to 200A.

That might work, but keep in mind that at 200 amps, you're going to have
the same power as a 1949 VW bug, in a vehicle that likely weighs quite a
bit more.

I'd say your acceleration will be lethargic, except that might be too
energetic a word.


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

It'll be a lead sled, similar to the same weight in 6V GC batteries at
half the voltage, 400 amps max. Or am I missing something?

-Morgan LaMoore



> Peter VanDerWal <[email protected]> wrote:
> >> So from all the postings on this thread, I am going to assume that if I go
> >> with the 12 x 12v batteries I should just keep an eye on my driving and
> >> try to minimize current to 200A.
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

For about the same weight and volume as the 12 T1275's, you could use 15 8V=
GC's. That would probably give you longer life, and would be cheaper also.=
The range is pretty much dependent on the total weight of batteries.

And, with 1000 lbs of floodies, you really don't need the 9 incher. Why no=
t use an 8 inch motor? That would seem more than adequate for an old bug, a=
nd would save you money, space, and weight. The 9 incher would make more se=
nse if you had AGM's, or a larger flooded pack.


Phil




> Date: Thu, 12 Jun 2008 11:08:44 -0700
> From: [email protected]
> To: [email protected]
> Subject: Re: [EVDL] New EV Batteries 6v vs 12v
> =

> =

> =

> =



> > Higgins wrote:
> > > =
> 
> > > I am ready to pick batteries for my EV conversion (I have an FB-4001A
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] New EV Batteries 6v vs 12v*

The bugs and busses are different animals. You can look them up at 
www.busdepot.com and they will have different part numbers.

Looking at my Beetle and Westfalia I can see that the bus has larger 
diameter tubes and the spcing is different.

Chris in Cookeville, TN



> Foster Furniture wrote:
> > I have owned both bugs and bus's it seems like the front beam assemblies
> > are very similar I have never tried to mount a bus unit on a bug but if
> > possible you would gain bigger brakes and I be leave 3/4 ton carrying
> ...


----------

