Range: 156Volts vs 312 volts

[David Nelson-5]

I'm trying to understand a little better the components which affect
range. Suppose I convert my S10 pickup and use a Zilla HV controller.
If I installed 26 T-145 how would the range compare to if I instead
installed 26 UB121100 12V AGMs (1846lbs vs 1872lbs) or are there too
many other differences between these two batteries. Maybe a better
comparison might be 25 T-145s for a 150v pack to  22 T-1275s for a 264
volt pack (1800lbs vs 1804lbs)?

I'm assuming that the higher voltage pack will reduce the battery
current and hence possibly gain something in range. Also, I'm trying
to decide whether to save longer and install an AC system (I have a 2
mile drop from my house and a few smaller hills so I'm also thinking
of the regen) or go with a DC system. About twice per month I have a
50mile round trip on the freeway where I could go 55 in the truck
lane. The hardest part is the final 2miles where I gain 450 ft in
elevation. I don't want to go too far past 50% DOD. Cor van de Water
figured this would be doable with his S10
(http://www.evalbum.com/694). My S10 is an extended cab version so I'm
sure it is a little heavier than his regular cab long bed.

Thank you for your ideas.
--
David D. Nelson

http://evalbum.com/1328

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[Lee Hart]

David Nelson wrote:
> I'm trying to understand a little better the components which affect
> range.

Range comes from pounds of batteries. It doesn't matter what "shape"
these pounds take; a few big ones versus many small ones, 6v or 8v or
12v -- if the packs weigh the same (and are the same type of battery),
range will be the same.

> Suppose I convert my S10 pickup and use a Zilla HV controller.
> If I installed 26 T-145 how would the range compare to if I instead
> installed 26 UB121100 12V AGMs (1846lbs vs 1872lbs) or are there too
> many other differences between these two batteries.

The weights are so close, that your range will be essentially the same.
There will be some minor difference because you are also changing
brands, and changing from a 6v to a 12v battery.

The differences will change many other factors, however! The 6v T-145
will have a much longer life than the 12v UB121100. With the same motor
and controller, the UB11100 will allow faster accelleration and better
hill climbing.

> I'm assuming that the higher voltage pack will reduce the battery
> current and hence possibly gain something in range.

No.

> Also, I'm trying to decide whether to save longer and install an AC
> system (I have a 2 mile drop from my house and a few smaller hills
> so I'm also thinking of the regen) or go with a DC system. About
> twice per month I have a 50mile round trip on the freeway where I
> could go 55 in the truck lane.

An AC system will cost 2-3 times more, and give you 10-20% more range.
AC systems are more sophisticated, with more features like regenerative
braking. You just have to decide if it's worth it to you.

> The hardest part is the final 2 miles where I gain 450 ft in
> elevation. I don't want to go too far past 50% DOD.

Any lead-acid pack will have trouble with this if it is more than 50%
discharged. You may have to climb that hill in first gear and drive very
slowly.

--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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[zevutah]

David said
"Maybe a better
comparison might be 25 T-145s for a 150v pack to  22 T-1275s for a 264
volt pack (1800lbs vs 1804lbs)? "

This is is a very interesting question and similar to one that I worked on recently. I found Uve's Battery page to be a great tool for looking at this question. The factory battery ratings are at the 20 hr rate and we need to discharge at a much faster ( 1/2 hr rate ) for an EV. Here are the numbers that I came up with using your 2 batteries listed above.
See http://www.geocities.com/CapeCanaveral/lab/8679/battery.html

T 145 6 volt battery 150 volt pack. qty 25
Peukert Exponent = 1.179  ( lower is better )
Amp Hr at 1/2 hr rate = 142
150 volt * 142 amp hr = 21,300 watt hr
21,300 divide by 350 watt hr per mile = 60.8 mile range ( 100% DOD )

T 1275 12 volt 264 volt pack. qty 22
Peukert Exponent = 1.252
Amp Hr at 1/2 hr rate = 74
264 volt * 74 amp hr = 19,536 watt hr
19,536 divide by 350 watt hr per mile = 55.8 mile range

They are pretty close, but the 6 volt option looks like slightly better range. I talked to the Trojan customer service about this question also and they told me that the 6 volt battery had more plates per cell and would thus handle a fast discharge rate better.

They also said the warranty on the 6 volt battery is 36 months and the 12 volt is only 30 months. I asked about failure rate and they said the 6 volt battery has a better record on reliability and the warranty reflects that.

My guess is that the higher voltage pack would have better acceleration and top speed. The lower voltage pack would have better range. Maybe others with more experience could comment on that.

Hope that helps,
Kyle
http://www.evalbum.com/1414
http://www.zevutah.com/

David Nelson-5 wrote:

I'm trying to understand a little better the components which affect
range. Suppose I convert my S10 pickup and use a Zilla HV controller.
If I installed 26 T-145 how would the range compare to if I instead
installed 26 UB121100 12V AGMs (1846lbs vs 1872lbs) or are there too
many other differences between these two batteries. Maybe a better
comparison might be 25 T-145s for a 150v pack to  22 T-1275s for a 264
volt pack (1800lbs vs 1804lbs)?

I'm assuming that the higher voltage pack will reduce the battery
current and hence possibly gain something in range. Also, I'm trying
to decide whether to save longer and install an AC system (I have a 2
mile drop from my house and a few smaller hills so I'm also thinking
of the regen) or go with a DC system. About twice per month I have a
50mile round trip on the freeway where I could go 55 in the truck
lane. The hardest part is the final 2miles where I gain 450 ft in
elevation. I don't want to go too far past 50% DOD. Cor van de Water
figured this would be doable with his S10
(http://www.evalbum.com/694). My S10 is an extended cab version so I'm
sure it is a little heavier than his regular cab long bed.

Thank you for your ideas.
--
David D. Nelson

http://evalbum.com/1328

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[EVDL Administrator]

All other things being equal, the best predictor of range is battery mass as
a percentage of vehicle weight.  Your proposed batteries are nearly equal in
mass, and they'll most likely deliver very similar range.

A few notes -

AGM batteries may deliver somewhat better range where you expect to
discharge the battery in appreciably less than an hour.  This would be the
case if you plan to race the EV, or if ast acceleration is more important to
you than range.  (Now that I look at that paragraph it seems contradictory -
AGMs will deliver better range if you don't care about range.  Hmmm. ;-)

AGM batteries usually have a higher cost per mile (or km), sometimes MUCH
higher.  I'm sure the numbers have changed, but about 7-8 years ago, I
calculated the per-mile cost of Optima batteries at about seven (!) times
that of flooded golf car batteries (that is, 600% higher).   Today lead
prices are very high so that's a bigger part of batteries' cost, and that
seems to have diminished the spread a bit.  The cost difference may also be
lower for Universal batteries, which are made in China and thus perhaps
cheaper than some other brands (however I get the impression that they're
not a first line battery with the quality of, say, Hawkers, so I'd want to
test a few for cycle life before assuming anything).  In any case, for some
people, the convenience of not watering or cleaning is worth a  difference
of even 600%.  (Not for me, however. ;-)

There are fewer choices in higher voltage DC controllers.

OTOH, most common AC EV drives are designed for higher voltages.

David Roden
EVDL Administrator
http://www.evdl.org/


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[Peter VanDerWal]

> Lee,
> I know we've had this thread before (over and over!), and I agree that for
> the most part range equates to weight, but if you double the pack voltage
> so that you are drawing one-half the current from the traction pack (for
> the same power), you should get a few more amp-hours, no?

No.

If you have the same number of batteries and wire them as buddy pairs for
156 or a single straight string for 312, then the individual batteries see
EXACTLY the same amps for a given total power output.

Yes you need twice as many amps at 156V, but the current gets split in
half across each battery in the pair.

If you are using a single string of large batts for 156V or a single
string of smaller batts for 312V, then (for a given weight) the large
batts will have about twice the capacity as the small bats and even though
they will see twice the current, the ratio of amps to amphour rating is
the same.



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[Dave (Battery Boy) Hawkins]

Lee,
I know we've had this thread before (over and over!), and I agree that for the most part range equates to weight, but if you double the pack voltage so that you are drawing one-half the current from the traction pack (for the same power), you should get a few more amp-hours, no? Maybe I should restudy Peukert's law! And now that I think about it, you are burning up less energy in waste heat in the connections. I do enjoy the lower current that the 192 volt pack of Orbs provides the RX-7 at highway speeds, unlike the S10...

David,
I have a 144 volt '89 extended cab S10, and it would be difficult to get more than 24 floodies in one, especially if you are going to have nice poly boxes (and maybe an inch of insulation). My truck would do 50-60 miles with 24 T-145's, but that is pushing the range of a lead brick! Although I got 20,000 miles out of that pack with deep discharges, you won't get that out of AGM's. Not to mention the additional cost of a charging system for sealed AGM's. Also, you mentioned a Zilla, and the 1K will work well in your lead brick.
Suck Amps,
BB

>Date: Sun, 11 May 2008 09:08:15 -0500
>From: Lee Hart
>
>David Nelson wrote:
>> I'm trying to understand a little better the components which affect
>> range.
>
>Range comes from pounds of batteries. It doesn't matter what "shape"
>these pounds take; a few big ones versus many small ones, 6v or 8v or
>12v -- if the packs weigh the same (and are the same type of battery),
>range will be the same.
>
>> Suppose I convert my S10 pickup and use a Zilla HV controller.
>> If I installed 26 T-145 how would the range compare to if I instead
>> installed 26 UB121100 12V AGMs (1846lbs vs 1872lbs) or are there too
>> many other differences between these two batteries.
>
>The weights are so close, that your range will be essentially the same.
>There will be some minor difference because you are also changing
>brands, and changing from a 6v to a 12v battery.
>
>The differences will change many other factors, however! The 6v T-145
>will have a much longer life than the 12v UB121100. With the same motor
>and controller, the UB11100 will allow faster accelleration and better
>hill climbing.
>
>> I'm assuming that the higher voltage pack will reduce the battery
>> current and hence possibly gain something in range.
>
>No.
>
>> Also, I'm trying to decide whether to save longer and install an AC
>> system (I have a 2 mile drop from my house and a few smaller hills
>> so I'm also thinking of the regen) or go with a DC system. About
>> twice per month I have a 50mile round trip on the freeway where I
>> could go 55 in the truck lane.
>
>An AC system will cost 2-3 times more, and give you 10-20% more range.
>AC systems are more sophisticated, with more features like regenerative
>braking. You just have to decide if it's worth it to you.
>
>> The hardest part is the final 2 miles where I gain 450 ft in
>> elevation. I don't want to go too far past 50% DOD.
>
>Any lead-acid pack will have trouble with this if it is more than 50%
>discharged. You may have to climb that hill in first gear and drive very
>slowly.
>
>--
>Ring the bells that still can ring
>Forget the perfect offering
>There is a crack in everything
>That's how the light gets in    --    Leonard Cohen
>--
>Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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[Roger Stockton]

Zevutah wrote:

> David said
> "Maybe a better
> comparison might be 25 T-145s for a 150v pack to  22 T-1275s
> for a 264 volt pack (1800lbs vs 1804lbs)? "
>
> This is is a very interesting question and similar to one
> that I worked on recently. I found Uve's Battery page to be a
> great tool for looking at this question. The factory battery
> ratings are at the 20 hr rate and we need to discharge at a
> much faster ( 1/2 hr rate ) for an EV. Here are the numbers
> that I came up with using your 2 batteries listed above.
> See http://www.geocities.com/CapeCanaveral/lab/8679/battery.html
>
> T 145 6 volt battery 150 volt pack. qty 25 Peukert Exponent =
> 1.179  ( lower is better ) Amp Hr at 1/2 hr rate = 142 150
> volt * 142 amp hr = 21,300 watt hr 21,300 divide by 350 watt
> hr per mile = 60.8 mile range ( 100% DOD )
>
> T 1275 12 volt 264 volt pack. qty 22
> Peukert Exponent = 1.252
> Amp Hr at 1/2 hr rate = 74
> 264 volt * 74 amp hr = 19,536 watt hr
> 19,536 divide by 350 watt hr per mile = 55.8 mile range

One drawback of this sort of comparison is that it assumes a fixed 1/2hr discharge, which is really working floodies at a rate where AGMs would probably perform better.

The fixed discharge duration assumption also neglects that the battery power that represents will vary from pack to pack even though the vehicle will require the same power with any pack of the same weight.

If we compare instead at a fixed power level (after all, the vehicle will draw the same power going down the road with the same weight of either battery onboard):

T145: 181Ah @ 75A; 150V * 75A = 11.25kW

11.25kW / 264V = 42.6A

T1275+: 102Ah @ 42.6A

T145:   181Ah * 150V = 27.15kWh
T1275+: 102Ah * 264V = 26.9kWh

Basically, the numbers are close enough to be considered a wash given the uncertainty involved in these sorts of estimates; either pack would deliver about the same capacity at the same power level (about 15HP).

Obviously, as one compares at shorter and shorter discharge durations the scale tilts toward the battery with the lowest Peukert value.

> They are pretty close, but the 6 volt option looks like
> slightly better range. I talked to the Trojan customer
> service about this question also and they told me that the 6
> volt battery had more plates per cell and would thus handle a
> fast discharge rate better.

I think this means that if your application requires 75A discharges, the 6V battery is a better choice.  However, in this case, for the same power the higher voltage string of 12V batteries is discharged at a lower rate and so they come out about the same.

> My guess is that the higher voltage pack would have better
> acceleration and top speed. The lower voltage pack would have
> better range. Maybe others with more experience could comment on that.

I would expect the range to be similar, provided the vehicle is driven similarly.  I would expect the higher voltage pack to provide a wider powerband and this should translate into better acceleration.

I would, howerver, expect the 6VGCs to last better than the 12ers.

1800lb options that haven't been considered here are 27x T125 = 162V, or 29x T105 = 174V.  The T105 option might be the cheapest simply because the T105 tends to be more favourably priced than its larger siblings.  Not sure how many there are to a pallet, but taking a full pallet of any model should translate to a better price also.

26x T125 = 156V, which would max out a Z1K-LV and save a few bucks vs going to the -HV model for only a few volts more is worth considering.

Cheers,

Roger.

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[Peter VanDerWal]

> T 145 6 volt battery 150 volt pack. qty 25 Peukert Exponent =
> 1.179  ( lower is better ) Amp Hr at 1/2 hr rate = 142 150
> volt * 142 amp hr = 21,300 watt hr 21,300 divide by 350 watt
> hr per mile = 60.8 mile range ( 100% DOD )

Well, I suppose that is true if you travel at 120 mph, since that's the
only way you can travel 60 miles while discharging the batteries in only
30 minutes (1/2 hr rate)

Plus, it's VERY important to note that the Peukert formula is just an
approximation of what to expect, it is NOT a perfect fit.
It is /somewhat/ accurate if you calculate the Peukert exponent with rates
that a similar to the rate you are trying to estimate.

I.e. if you use the 10 hr discharge rate and the 20 hr discharge rate to
calculate the Peukert exponent, and then try to use this to calculate the
1/2 hr discharge rate, the results will likely be very different from
reality.


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[Jeff Shanab]

>
> Lee,
> I know we've had this thread before (over and over!), and I agree that for the most part range equates to weight, but if you double the pack voltage so that you are drawing one-half the current from the traction pack (for the same power), you should get a few more amp-hours, no?


I would say only if amphours is kept constant. And then of course the
pack weights twice as much. For the same weight you are now pulling
twice the C-rate of the battery. This is at least how the battery sees it.

I have a 288V pack and part of getting that within a weight I could
manage was using AGM's. Excide Orbitals. But to be honest, I believe the
15% or so the orbital design wastes in air space is, well, a waste. SO
my pack ended up less than 1/2 an equivilent volume of 6 volters would
have been. I am looking at trying Deka Dominators or hawkers, But
lithium is my goal.

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[Ralph-54]

On Sun, 11 May 2008 09:08:15 -0500
Lee Hart <leeahart@...> wrote:


> An AC system will cost 2-3 times more, and give you 10-20% more range.
> AC systems are more sophisticated, with more features like regenerative
> braking. You just have to decide if it's worth it to you.
>

FWIW I got my AC kit from Electro Automotive; the cost was about 25% more, not 2-3 times. I went with the Azure Dynamics system as it is air-cooled. It is less expensive than the other AC systems (AC Propulsion and Siemens); those systems really do cost 2-3 times more! I figured since the range **at best** is only 100 miles, that air-cooling won't make that much difference up here on the flats in Minnesota! We have a variety of cooling options if I am plain wrong about that...

-Ralph

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[John G. Lussmyer]

Ralph wrote:
> FWIW I got my AC kit from Electro Automotive; the cost was about 25% more, not 2-3 times. I went with the Azure Dynamics system as it is air-cooled. It is less expensive than the other AC systems (AC Propulsion and Siemens); those systems really do cost 2-3 times more! I figured since the range **at best** is only 100 miles, that air-cooling won't make that much difference up here on the flats in Minnesota! We have a variety of cooling options if I am plain wrong about that...
>  

25% more than what?

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[Ralph-54]

About 25% more than the cost of the DC conversion kit.


On Mon, 12 May 2008 12:16:58 -0700
"John G. Lussmyer" <Cougar@...> wrote:

> Ralph wrote:
> > FWIW I got my AC kit from Electro Automotive; the cost was about 25% more, not 2-3 times. I went with the Azure Dynamics system as it is air-cooled. It is less expensive than the other AC systems (AC Propulsion and Siemens); those systems really do cost 2-3 times more! I figured since the range **at best** is only 100 miles, that air-cooling won't make that much difference up here on the flats in Minnesota! We have a variety of cooling options if I am plain wrong about that...
> >  
>
> 25% more than what?
>
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[Peter VanDerWal]

Diesel powered cars have very little compression braking and seem to be
able to descend hills safely.

Considering the limited amount of hill that you can climb, I don't think
you'll have enough downhill to cause any serious problems for the brakes.

I think this is practically a non-issue.

> On Mon, May 12, 2008 at 1:59 PM, storm connors <stormconnors@...>
> wrote:
>
>> I have a similar situation re elevation. Regen won't buy you anything
>> if your batteries are fully charged when you leave home. Electric cars
>> are happier when you live in the valley rather than the mountaintop.
>>
>
>>From an energy perspective, it might not, but from a not crashing
> perspective, if you add a giant resistor bank to burn it up as you descend
> the hill, it still might be useful....
>
> Z
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[storm connors]

I have a similar situation re elevation. Regen won't buy you anything
if your batteries are fully charged when you leave home. Electric cars
are happier when you live in the valley rather than the mountaintop.

>   (I have a 2
>  mile drop from my house and a few smaller hills so I'm also thinking
>  of the regen) or go with a DC system.
>  David D. Nelson
>
>
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>

--
http://www.austinev.org/evalbum/1059
http://stormselectric.blogspot.com/
Storm

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[Zeke Yewdall]

On Mon, May 12, 2008 at 1:59 PM, storm connors <stormconnors@...>
wrote:

> I have a similar situation re elevation. Regen won't buy you anything
> if your batteries are fully charged when you leave home. Electric cars
> are happier when you live in the valley rather than the mountaintop.
>

>From an energy perspective, it might not, but from a not crashing
perspective, if you add a giant resistor bank to burn it up as you descend
the hill, it still might be useful....

Z
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[Bob Rice-2]

----- Original Message -----
From: "Peter VanDerWal" <evdl@...>
To: "Electric Vehicle Discussion List" <ev@...>
Sent: Monday, May 12, 2008 3:28 PM
Subject: Re: [EVDL] Range: 156Volts vs 312 volts


> Diesel powered cars have very little compression braking and seem to be
> able to descend hills safely.

    Huh? What? Diseasel cars compression brake just fine! Hell you need a GP
27 battery to crank the damn things when it's cold! Of course they go down
hills great in low gear, like throwing out the anchor!

> Considering the limited amount of hill that you can climb, I don't think
> you'll have enough downhill to cause any serious problems for the brakes.
>
> I think this is practically a non-issue.

       In hilly CT hasn't been an issue! Out west with MILES of downgrade it
COULD be an issue, though?

>> On Mon, May 12, 2008 at 1:59 PM, storm connors <stormconnors@...>
>> wrote:
>>
>>> I have a similar situation re elevation. Regen won't buy you anything
>>> if your batteries are fully charged when you leave home. Electric cars
>>> are happier when you live in the valley rather than the mountaintop.

          But isn't it true MOST EVers live on hill tops<g>?
>>
>>>From an energy perspective, it might not, but from a not crashing
>> perspective, if you add a giant resistor bank to burn it up as you
>> descend
>> the hill, it still might be useful....

     Might take the chill off this "spring" weather!?

        Seeya

        Bob, getting in a few words edgewise.

>>
>> Z
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>>
>
>
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[David Nelson-5]

I really appreciate everyone's responses. It sounds like I need to
keep in mind what I've been reading over the past year or so that no
EV conversion is really ever finished and that I can always build
another one after getting more experience under my belt.

On the cost side of things it looks like I'd be ahead to go with 6v
flooded and a low voltage Zilla. If I read Otmar's web site correctly
that if I needed to go to a higher voltage later I could have him
upgrade my controller.

As for an AC system I like the idea of having regen, not so much for
any range I might gain, but for braking. I know that I wouldn't get
too much regen buffer in a full pack but there should be a little,
especially if my Gizmo is any indication (SepEx motor, T-875s). I
don't need much but I do occasionally have a 0.5mi steep down hill
with a stop at the bottom. The reality is that if this were too much I
could take the long way around. As Peter said below:
On Mon, May 12, 2008 at 12:28 PM, Peter VanDerWal <evdl@...> wrote:
> Diesel powered cars have very little compression braking and seem to be
>  able to descend hills safely.
>
>  Considering the limited amount of hill that you can climb, I don't think
>  you'll have enough downhill to cause any serious problems for the brakes.
>
>  I think this is practically a non-issue.

It may be a non-issue as long as braking safety isn't a problem. I do
know that with my Gizmo that regen is a net loss during the last
little bit of regen. My volt meter dips below rest voltage and
periodically my PakTrakr shows a negative current at the end of regen.
I use regen because I burn through brake pads too fast. I'm sure I'll
get more life out of the S10's pads. I just can't imagine them being
gone after 3000miles.

I need a truck load of sand. Maybe I'll pick it up in my S10 and go
down my hill to get an idea of what it feels like. The weight might
not be the same but it'd give me a clue.

Besides a possible (I'm comparing to a Zilla) higher cost for
something like the Asure system another disadvantage is that I'd need
at least 288V so I'd need to go with 12V batteries.

I like living up a hill but I know my Gizmo doesn't. The slowest
assent was on a cold December night after going to and through a
parade. My digital speedometer read 00 on the last 1/10th of a mile
before cresting the hill. The rest voltage after getting home was
still in the "safe zone."

Thank you again.

--
David D. Nelson

http://evalbum.com/1328

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