# Audi TT kostov 11" soliton 1, Whats the best battery pack?



## somanywelps (Jan 25, 2012)

You already have the motor and controller?


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## dreamer (Feb 28, 2009)

I don't know about "good and sound advice" as I only know what I've distilled from others on these pages over the last few years. But ...

You say performance is not a priority, but with a 192V 100ah pack or prismatic cells, you will not have more than 100kw of power max from the cells and only 80kw or 105hp to the transmission. That's because prismatics -- no matter what brand -- can't be relied on for more than about 5C their amp hour rating. 65 100ah prismatics will set you back roughly $8K. That's a 20KWH pack and might meet your 70 mile range if you ran it dead. 45 160ah cells will produce more amps, and therefor torque, but still only 115hp and only 1KWH more capacity at a cost of $9K.

That is significantly less power than the ICE TT. It is also only half the amps the Soliton can handle and under utilizes the 11" Kostov , which seems wasteful.

Buying a large qty of Headway cells, I think you might get the high power 8ah cells for under $13/ea. $8K of Headways could be 560 cells (70s8p) and a 14KWH battery pack. Not going to get you 70 mile range, but it would better utilize your Soliton and put 200hp+ to the transmission. 

390 cells (65s6p) of 15ah low power Headways would be about the same cost for a 18KWH pack closer to meeting your range requirement, but still putting out 190hp+. 

I don't think the additional range of the prismatics is worth the reduction in performance.


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## somanywelps (Jan 25, 2012)

The CALB cells can do 8C-12C burst depending on how many seconds you want to do it, but you're going to get mad voltage sag (30-45%).

The correct action would be to take the battery voltage up to 320-340V at full charge, and let the soliton drop the voltage for the motor.

Also doesn't sag below the motor voltage.


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## dreamer (Feb 28, 2009)

So 100 cells in series of 100ah cells gets you a brief burst of 200kw ? At a cost of $12K if each cell is $120. That's 30KWH and easily meets the range requirement. It gets you the performance and the range, but at 50% increase in cost. Or you could build it from 40ah CALBs for $10K but strain the cells and barely meet the range requirement. 

If he was willing to spend $12K on the cells, he could use 560 15ah Headways at 224v and 120ah, still meet his range requirement of 70 miles, and get max performance from the 192v motor and Soliton without straining the cells and without the same level of voltage sag.

Having to buy more CALB cells to allow for voltage sag seems to negate the price advantage over Headways, doesn't it ?


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## somanywelps (Jan 25, 2012)

dreamer said:


> So 100 cells in series of 100ah cells gets you a brief burst of 200kw ? At a cost of $12K if each cell is $120. That's 30KWH and easily meets the range requirement. It gets you the performance and the range, but at 50% increase in cost. Or you could build it from 40ah CALBs for $10K but strain the cells and barely meet the range requirement.
> 
> If he was willing to spend $12K on the cells, he could use 560 15ah Headways at 224v and 120ah, still meet his range requirement of 70 miles, and get max performance from the 192v motor and Soliton without straining the cells and without the same level of voltage sag.
> 
> Having to buy more CALB cells to allow for voltage sag seems to negate the price advantage over Headways, doesn't it ?


No, because they sag compensation winds up giving you more KWH anyway. Which he wanted.

It's just a parallel series thing.


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## skooler (Mar 26, 2011)

Hi Martin,

The general consensus is normally to go for the highest voltage possible (350V with the Soliton). This means that when the cells are under sag, you can still get full voltage to the motor. Remember battery volts and amps are not the same as motor volts and amps - you can convert battery volts to motor amps but not the other way round.

Worst case is that you'll need 350WH/Mile

350WH * 70 miles is 24,500WH - the usable portion of the pack

24500 /0.8 is 30625WH (30.6KW) - the 0.8 is the depth of discharge you'll run the pack to.

30625WH / 350V is 87.5AH

So you'll need a 350V, 87.5AH pack for 70 miles. - perhaps 100 * 100AH cells?

The same calculation but starting with 300WH/Mile gives you 26.25KWH - or 350V, 75AH.

Hope this helps.

Cheers,

Mike


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## somanywelps (Jan 25, 2012)

Just to expound, you don't actually want 350V exactly, there should be a little leeway below that.

The soliton will fault if you ever get above 350V and that's annoying.


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## Yabert (Feb 7, 2010)

If you don't need high performance, don't bother with high quantity of headway cells. Stay with prismatic.
But you will need more than 20 kwh of energy storage to acheive your goal.

The Skooler numbers seem right (300-350 wh/mile), so if you go with 90 100Ah cells that give:

90 x 3.2 = 288v nominal x 100Ah = 28.8 Kwh x 0.8 = 23 Kwh 
23 Kwh / 350 wh/mile = 65 miles
23 Kwh / 300 wh/mile = 76 miles

So, that depend of the speed of your traveling. 
For example, 21 Kw (350 x 60) to maintain 60 mph seem right or even a bit high.
And 12 kw (300 x 40) to maintain 40 mph seem right.

And by the way, with over 180 Kw available from battery, that will give you pretty good performances.


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## TTmartin (Feb 7, 2012)

skooler said:


> The general consensus is normally to go for the highest voltage possible (350V with the Soliton). This means that when the cells are under sag, you can still get full voltage to the motor. Remember battery volts and amps are not the same as motor volts and amps - you can convert battery volts to motor amps but not the other way round.
> 
> 
> Hi Mike,
> ...


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## skooler (Mar 26, 2011)

TTmartin said:


> Hi Mike,
> 
> The TT is the doner car because I've always liked the look of them but I'm really not interested in the performance. Picked the the car up cheap with a dead engine, thought this would be an interesting project
> I've got the Kostov 11" and soliton 1 for versatility for future upgrades maybe? My son seems rather interested.
> ...


Hi Martin, The figure I gave you was for the amount of energy storage required to get the 70 miles range.

With higher energy the power available typically rises


energy = range
power = performance

65 * 100AH cells is 20.8KWH of energy - about 50 miles range

Because of the correlation between energy and power, you'll have about 110KW of power available (at 5C)- thats roughly 150HP before efficiency losses. the soliton will let you limit this.

1hp = 0.746KW

Am I making sense?

Cheers,

Mike


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## Tesseract (Sep 27, 2008)

skooler said:


> The general consensus is normally to go for the highest voltage possible (350V with the Soliton). ...


Sort of. You can theoretically run a 100s LFP pack with the Soliton1 or Jr controllers, now, but you have to limit your maximum charging voltage to get away with it.




TTmartin said:


> ...
> For me, if I can get the car to equal say, a ford fiesta 1.4 diesel in performance with a respectable range, I will be more than happy,
> so that's where my 60 to 65 100ah cells, figure came from, or am a way off the mark?
> I was assuming you can set controller to performance requirement.
> ...


A forum tip, first: close any quoted text with the tag [/quote]

60-65 100Ah cells should give you pretty decent performance even with the higher-voltage Kostov. You really shouldn't try to push a full 1000A through the K11 for more than a couple seconds at a time. With the lower pack voltage comprised of 100Ah cells you will have some automatic protection against that, but in the beginning I would leave the battery and motor current limits set to their default values (400A and 800A, respectively).

That said, don't assume you can set the controller, Read The Fine Manual (download from this page) and be sure of it!


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## TTmartin (Feb 7, 2012)

skooler;
energy = range
power = performance
65 * 100AH cells is 20.8KWH of energy - about 50 miles range
Because of the correlation between energy and power said:


> Hi mike,
> I feel like I'm back in school  yes that all makes sense.
> thankyou for your help.
> 
> ...


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## TTmartin (Feb 7, 2012)

Tesseract said:


> Sort of. You can theoretically run a 100s LFP pack with the Soliton1 or Jr controllers, now, but you have to limit your maximum charging voltage to get away with it.
> 
> 60-65 100Ah cells should give you pretty decent performance even with the higher-voltage Kostov. You really shouldn't try to push a full 1000A through the K11 for more than a couple seconds at a time. With the lower pack voltage comprised of 100Ah cells you will have some automatic protection against that, but in the beginning I would leave the battery and motor current limits set to their default values (400A and 800A, respectively).
> 
> That said, don't assume you can set the controller, Read The Fine Manual (download from this page) and be sure of it!


Thankyou very helpful,

the manual is on my [to do list] controller ordered but not with me yet.

when I first got this crazy idea to convert a car to EV, 3 months ago I read the curtis manual from cover to cover thinking that is what I would use but things change when your not sure what your doing
Im getting there thanks to the many helpful people on this forum


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