# Planning MG Kit Car (68 VW Bug) Conversion



## DavidDymaxion (Dec 1, 2008)

The old MG is a great looking car.

Since you only need to go 6 miles, you might consider going with used batteries -- check with golf courses, places that replace UPS batteries, etc.

VWs are among the most common conversions, you might be able to find a used motor adapter.

Also, you might want to consider using Lithiums. If you could live with 35 mph and slow acceleration, then around 48V of 100 Ahr Lithiums would cost around $2000 and probably be enough to get you to work. You could then add a battery a month after that.


ubersmart said:


> Hi all!
> 
> I have a professionally built MG kit car that's been sitting in my carport for the last 10 years. (I won't bore you with the details.) Anyway, a friend of mine peaked my interest by sending me a link to e-volks.com and I've managed to talk my wife into letting me do the conversion. New tires were installed and the engine was pulled within days of that decision.
> 
> ...


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## Duncan (Dec 8, 2008)

Hi Uber

Sounds like a fun conversion,

If you are a real cheapskate like me..

My car
Home built 2 seater (locost like)
Forklift motor $100
OpenRevolt Controller $600

Batteries
I am using a small pack of Headways 
44 series 2 parallel Headway 16Ah
This should give - 30Km range
but low cost and only 50kg weight

much better than lead!


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## Ziggythewiz (May 16, 2010)

ubersmart said:


> I was looking at Kit #3 (120V kit) at e-volks.com. After reading some stuff on this forum, I'm leaning towards looking elsewhere. I'd still like an affordable kit that has most of what I need. Suggestions?


I used most of their kit 3 (74 vw bug) total cost ~$6k.

Issues: Coupler splines wore down after 8 months of driving, they replaced it with no issues. Supposedly they have switched to a new springy type but my replacement was the old.

Other than that everything works great.

Regrets: Should have gone 144V.
Also would like to have built my own controller and charger to get much more for less, but that gets into that electronic stuff you probably aren't interested in.


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## ubersmart (Jan 3, 2012)

Thanks for the response!



DavidDymaxion said:


> The old MG is a great looking car.


Thanks, I get people knocking on my door all the time asking me if it's for sale.



DavidDymaxion said:


> Since you only need to go 6 miles, you might consider going with used batteries -- check with golf courses, places that replace UPS batteries, etc.


 An intriguing idea, but I'm not sure I'd be comfortable with old worn out batteries. I assume someone's done this? What were the results?



DavidDymaxion said:


> VWs are among the most common conversions, you might be able to find a used motor adapter.


Any suggestions other than Google on where I would look?



DavidDymaxion said:


> Also, you might want to consider using Lithiums. If you could live with 35 mph and slow acceleration, then around 48V of 100 Ahr Lithiums would cost around $2000 and probably be enough to get you to work. You could then add a battery a month after that.


Ouch! That's $500 / 12 V. I spend about $80 / mo. on gas, so maybe I could afford 12 V every 6 months (completely ignoring the added electricity cost.) I don't think I'd be willing to live with a top speed of 35 mph for that long.


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## Duncan (Dec 8, 2008)

_around 48V of 100 Ahr Lithiums would cost around $2000 and probably be enough to get you to work. You could then add a battery a month after that._

rather than 48v x 100Ah prismatics I went for 150v x 32Ah Headway - similar cost but I am hoping for 80Mph and 5 seconds 0-60


100Ah prismatic limited to 3C - 300 amps

32Ah Headway - 10C continuous or 15C burst = 320amps or 480 amps

Range is similar but available power is

Prismatic - 48v x 300 amps = 14.4Kw
Headway - 150v x 480 amps = 72 Kw

That is about as much as my controller can handle

and when I want more I can add another string or increase the voltage (after upgrading the controller)


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## GizmoEV (Nov 28, 2009)

Since you have to install the motor, controller, charger, and things before the battery boxes why not start installing things as you get them and when you have a better idea of how much money you have left to spend then order your batteries. If you decide on a charger which can be programmed for any battery type then you can design for the charger location without actually buying it so that you can order it after choosing the batteries.

When you build your battery boxes design them so you can change battery types relatively easily so you don't have to start over when you change sizes.

After running with lead acid and then switching over to LiFePO4 cells I don't ever plan on doing a lead acid conversion. In the last two years I have driven over twice as many miles as I got from my Trojan T-875 pack. At this rate I'll be at my break even point in around 5 years and that isn't even counting the fact the the much longer range means I have driven my EV way more and replaced many ICE miles so my pay pack is more like 4 years or less. This is even though I bought a pack twice the size I needed to just replace the lead acid functionality. It is definitely something you want to consider. If you must go the lead acid route I would seriously consider the used battery route if you can find some GC batteries. 12 miles shouldn't be too hard to get. Check on evalbum.com and the Garage on this site to get an idea of the Wh/mi figures of similar vehicles so you can figure out how much energy you will need.


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## ubersmart (Jan 3, 2012)

Ziggythewiz said:


> I used most of their kit 3 (74 vw bug) total cost ~$6k.
> 
> Issues: Coupler splines wore down after 8 months of driving, they replaced it with no issues. Supposedly they have switched to a new springy type but my replacement was the old.
> 
> ...


I took a closer look at the differences between the 120V and the 144V kits (now that I've done some reading here on the subject and am better informed) and the 144V kit does look to be the better choice. Hmm, I think ya'll are talking me into busting my budget.


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## ubersmart (Jan 3, 2012)

Duncan said:


> rather than 48v x 100Ah prismatics I went for 150v x 32Ah Headway - similar cost but I am hoping for 80Mph and 5 seconds 0-60
> 
> 
> 100Ah prismatic limited to 3C - 300 amps
> ...


That, I could live with (I think). As you said, I could always add another string to increase the range, but it starts me off with what I need. What kind of range could I expect. Better yet, can someone give me an equation for calculating expected range where I can just plug in the variables?


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## Ziggythewiz (May 16, 2010)

ubersmart said:


> the 144V kit does look to be the better choice. Hmm, I think ya'll are talking me into busting my budget.


I used their kit as a shopping list, and found cheaper sources for a few of the bigger ticket items. Anything over $100 I shopped around to see if their price was lowest/close enough to be worth saving time. If you can find welding wire locally you can save a bunch there as it's dead weight to ship.


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## ubersmart (Jan 3, 2012)

Ziggythewiz said:


> I used their kit as a shopping list, and found cheaper sources for a few of the bigger ticket items. Anything over $100 I shopped around to see if their price was lowest/close enough to be worth saving time. If you can find welding wire locally you can save a bunch there as it's dead weight to ship.


I started to do the same, but I added up the prices they listed for the individual components and compared it to the kit price. Turns out there's a significant discount built into the kit price. I might be able to save a few bucks by shopping around, but I'd really have to get some good deals to make it worth the time and effort.


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## Duncan (Dec 8, 2008)

_Better yet, can someone give me an equation for calculating expected range where I can just plug in the variables?

_There are a few but I'm not sure how good they are as there are so many variables

Rough
Battery capacity x 0.8 (don't want to use more than 80% for life)(lithium)
For a lightweight car
Low speed light foot - use 200 watthours/mile
high(er) speed heavy foot - use 300 watthours/mile


So for my pack - 44 x 3.3volts x 16 Ah x 2 = 4650 = 4.6Kwhours

4.6 x 0.8 = 3.7 Kwhours - useable

3700 / 200 = 18.5 miles
3700 / 300 = 12.3 milesI think this will be enough for me to start with_, _the cells are ~ $20 each so $1760 for the pack


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## ubersmart (Jan 3, 2012)

Duncan said:


> _Better yet, can someone give me an equation for calculating expected range where I can just plug in the variables?
> 
> _There are a few but I'm not sure how good they are as there are so many variables
> 
> ...


Thanks!

A quick search yielded prices from $24 to $35 for each cell. Can I get them cheaper? If so, where?


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## GizmoEV (Nov 28, 2009)

Duncan said:


> So for my pack - 44 x 3.3volts x 16 Ah x 2 = 4650 = 4.6Kwhours


My real world data suggests that using 3.2V or even 3.15V as a nominal energy calculating voltage would be better. When I take the Wh and Ah numbers given by my CycleAnalyst divide them that is the range of numbers I get when the batteries are over 10°C.

Also, if you build for 80% of capacity just fitting your range and you aren't able to add to your pack in a relatively short period of time you will soon be using more than 80% of the available capacity as the cell's capacity declines. If your commute is 12 miles round trip I highly recommend you get a pack for double that if at all possible.

Also, from personal experience and that of others, it is quite possible to run without a BMS for at least a year if not two years. You might want to consider that but definitely get informed about how to care for your batteries if you don't use a BMS. It is not hard but it is also not hard to kill them quickly if you don't take some simple precautions.


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## Duncan (Dec 8, 2008)

Hi Uber_

A quick search yielded prices from $24 to $35 for each cell. Can I get them cheaper? If so, where?

_I got mine direct from china

E-Mail Lorraine - [email protected]

My shipping costs were on top but in New Zealand anything I buy has shipping on top


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## ubersmart (Jan 3, 2012)

Thanks to everyone that replied! Based on your feedback, I've convinced myself, and more importantly my lovely bride, to "borrow" a couple grand from other areas in our budget to make better choices.

I'm planning on using Kit #4 (144V) from e-volks.com:
* Advanced #FB1-4001 motor
* Curtis 1231C controller
* Allbright SW200 contactor
* 500 amp shunt
* 400 amp slow blow fuse
* 144V and 12V Smart Chargers
* adapter plate
* coupler [uses clutch]
* throttle box
* voltage and amperage gauges

For the battery pack I'm planning on using 88 Headway 16ah cells (44s2p) and miniBMS.

Any major components missing? Any concerns? Is the voltage of the battery pack correct (correct number of cells in series)?


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## Yabert (Feb 7, 2010)

I personnaly think than e-volks kit contain some cheap parts for the price. Some parts nice to have 10 years ago...
Charger, controller and probably some other parts seem obsolete. 

If I have to build your car, I will probably choose Soliton Jr controller, Elcon charger and EV Display as current/voltage meter.

Also, I think you can build a 48S 2P battery pack (or more in series) to have a bit more peak power and range. 44s is 140v nominal, but this voltage will probably drop under 125v in some situation.


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## Ziggythewiz (May 16, 2010)

Are you planning to use a DC-DC or just the 12V charger for your Aux Batt?
I started out using the 12V (not theirs, as I already had one) then switched to a wall wart size float charger, then ditched that for a solar panel. Except for night driving, the power drain is miniscule.

*Can the quickcharger do lithium?* Mine can be set for a variety of lead options, but no lithium.


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## mora (Nov 11, 2009)

I'd say you can get all those parts included in kit #4 for less than 5000$ if you buy them elsewhere. Most parts will be better like Yabert said already. Motor should be something like 2000$ (FB1-4001), controller 2000$ (Soliton Jr) or 600-1000$ (prebuilt OpenRevolt or equivalent), charger something like 500$ (ElCon) and rest of the stuff will fit there in remaining amount. Could be even less than 4000$ for those parts. Leaves more funds for batteries.


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## madmike8 (Jun 16, 2011)

The Rebirthauto.com kit doesn't look bad either... bit more but with Soliton Jr, Kostov 9 and Elcon 1500w Charger


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## DavidDymaxion (Dec 1, 2008)

If you want power more than range it would be better to go with the 8 Ahr "P" cells.

16 Ahr $32 8 milliOhm
8 Ahr $19 4 milliOhm

For $64 you could do two 16 Ahr cells in parallel, or for $57 you could do three 8 Ahr P cells in parallel.

two 16 Ahr cells in parallel => 4 mOhm => 2 V drop per parallel block => You would pull your cells well below 2.0 V, damaging them. Your pack Voltage would be sagging to below 1/2 Voltage. Total pack power = 500 A * 44 series * (3.4 V - 500 A * 0.004 Ohm) = 31 kW (ouch! slow!)

three 8 Ahr P cells in parallel => 1.3 mOhm => 0.65 V drop per parallel block => Cells at safe Voltage => 60 kW of power (much happier driver!)

At low currents you are giving up some range (although it might actually go further at higher currents due to less internal resistance loss). If you could spend a bit more ($76 vs. $64 per parallel block) then you'd have all the range and even more power.



ubersmart said:


> Thanks to everyone that replied! Based on your feedback, I've convinced myself, and more importantly my lovely bride, to "borrow" a couple grand from other areas in our budget to make better choices.
> 
> I'm planning on using Kit #4 (144V) from e-volks.com:
> * Advanced #FB1-4001 motor
> ...


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## ubersmart (Jan 3, 2012)

Ziggythewiz said:


> Are you planning to use a DC-DC or just the 12V charger for your Aux Batt?
> I started out using the 12V (not theirs, as I already had one) then switched to a wall wart size float charger, then ditched that for a solar panel. Except for night driving, the power drain is miniscule.
> 
> *Can the quickcharger do lithium?* Mine can be set for a variety of lead options, but no lithium.


I just plan on using the 12V charger. DC-DC converter would be better, but for the short distances I'll be driving I doubt it'll be an issue.

Good question on the quickcharger. I asked Brian if the kit would work with the battery pack I described and he thought it would, but I meant to specifically ask about the charger and forgot to do so. I sent him an email earlier today but haven't heard back from him yet.


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## ubersmart (Jan 3, 2012)

DavidDymaxion said:


> If you want power more than range it would be better to go with the 8 Ahr "P" cells.
> 
> 16 Ahr $32 8 milliOhm
> 8 Ahr $19 4 milliOhm
> ...


Hmm, thanks for the education. I was ignorant of the ramifications of the batteries' internal resistance, but after reading this *several* times I think I finally understand.


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## ubersmart (Jan 3, 2012)

Take 3:

Let me know if you see any *technical* issues.

Battery pack: 48 Calb 40ah cells with miniBMS.

*Modified* Kit #4 (144V) from e-volks.com:
* *WarP ImPulse 9* motor
* Curtis 1231C controller
* Allbright SW200 contactor
* 500 amp shunt
* 400 amp slow blow fuse
* *12V* Smart Charger
* *customized* adapter plate
* coupler [uses clutch]
* throttle box
* voltage and amperage gauges

The reason for the customized adapter plate and smaller motor is because I only have 17" between the transmission and trunk lid. 

I have not researched chargers yet. Suggestions? (Please keep my limited budget in mind.)

FYI, although I think the EV Display is really cool, it would look terribly out of place in my car. The e-volks gauges, on the other hand, will replace the gas gauge and oil pressure gauge in my dash perfectly.


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## Ziggythewiz (May 16, 2010)

ubersmart said:


> Take 3:
> Battery pack: 48 Calb 40ah cells with miniBMS.


What's the max and continuous rating of those calbs?


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## Yabert (Feb 7, 2010)

Hey Ub, why do you like E-Volks parts like that?

Please don't pay 1700$ for an obsolete Curtis controller.
From different site, I see:

1500$ Warp Impulse (I use it. Nice small motor)
1900$ Soliton Jr (lot of nice feature and a lot more power capability than Curtis)
530$ Elcon 1500w charger




ubersmart said:


> FYI, although I think the EV Display is really cool, it would look terribly out of place in my car. The e-volks gauges, on the other hand, will replace the gas gauge and oil pressure gauge in my dash perfectly.


Maybe can you explain the difference between 2" EV Display VS 2" E-Volks gauges...


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## ubersmart (Jan 3, 2012)

Ziggythewiz said:


> What's the max and continuous rating of those calbs?


According to http://currentevtech.com/Lithium-Batteries/CALB/CALB-40ah-cell-p28.html, 4C continuous and 12C burst.


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## ubersmart (Jan 3, 2012)

Yabert said:


> Hey Ub, why do you like E-Volks parts like that?
> 
> Please don't pay 1700$ for an obsolete Curtis controller.


There are many good arguments on both sides of buying a pre-packaged kit from a single vendor vs. buying "best of breed" from various sources. I'd rather not get into those here. Suffice to say, I'm opting for the former. 

I see the Curtis controller used around here quite often. Other than it being "old" what's wrong with it? What I pay for it is between me and the folks at e-volks.  



Yabert said:


> Maybe can you explain the difference between 2" EV Display VS 2" E-Volks gauges...


Sure! One's digital, the other is analog. My car is a *replica* of a 52 MGTD. A digital display would look terribly out of place.


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## Ziggythewiz (May 16, 2010)

ubersmart said:


> According to http://currentevtech.com/Lithium-Batteries/CALB/CALB-40ah-cell-p28.html, 4C continuous and 12C burst.


That doesn't give a whole lot of power with 40ah cells. I imagine even the curtis and warp9 could exceed that. Mine's a slug, but even it can get to 400, which is close to your burst.


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## madmike8 (Jun 16, 2011)

ubersmart said:


> There are many good arguments on both sides of buying a pre-packaged kit from a single vendor vs. buying "best of breed" from various sources. I'd rather not get into those here. Suffice to say, I'm opting for the former.
> 
> I see the Curtis controller used around here quite often. Other than it being "old" what's wrong with it? What I pay for it is between me and the folks at e-volks.


You could try Rebirth Auto's package. I haven't used them, but I haven't heard anything bad from those that have either...
*
http://rebirthauto.com/rebirthautoclassisvwperformancemileagekit.aspx

Features Include:
*​ *Motor:Kostov 9-inch 144V Motor*​ *Motor Adapter: RebirthAuto VW Motor Adapter*​ *Motor Controller:Evnetics SolitonJr 600 Amp Motor Controller
*​*Throttle:Evnetics Throttle Pot*
*Charger:Elcon PFC1500Watt Charger Dual-Input*
*DC/DC Converter:Elcon DC/DC Converter 12.5A*
*Hardware:Complete Hardware Kit (includes contactors, fuses, fuse holders, wiring, crimp lugs, emergency stop, etc.)*
*Freebies:RebirthAuto T-Shirt and Stickers*
* Documentation:Wiring Schematics*


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## EVfun (Mar 14, 2010)

My Winston cells claim 3C continuous and 20C impulse. They are good for about 7C. If the CALB cells you are looking at are actually good for about 8C then you would have a peak battery current of 320 amps. 

My 60 amp hour cells have an internal resistance of about 1.5 milliohms at 65F (more like 1.8 milliohms at 45F.) Without knowing someone using current CALB 40 amp hour cells at high C discharge rates it is hard to know the DC internal resistance. The published internal resistance number is based on an AC impedance test. It will always be far lower than the actual internal resistance. I will just toss out 2 milliohms for the 40 amp hour cells as my best guess. 

My cells sag to about 2.65 volts at 420 amps. I am guessing 40 amp hour CALB cells would sag to about the same at 320 amps. Your 153 volt (nominal) pack would sag down to about 127 volts at peak load. You would have about 46 peak motor shaft horsepower. If they where cold it would quickly get worse. This will work fine for a VW kit car, but may not be the kind of performance you have in mind. 

I like the little 40 ah cells because it seems one of the more standardized sizes (4.6" by 1.8" by 7.3" tall.) They are just a bit current limited. I recently increased my Beach Buggy pack from 32, 60 amp hour cells with a peak current of 420 amps to 38, 60 amp hour cells with a peak current of 360 amps. I have about 43 horsepower for an EV that weighs less than 1200 lb. Most EV kit cars (especially ones based on production cars) will weigh more than that. 

I would agree with Yabert on the choice of an Elcon charger. Though I prefer the Manzanita Micro PFC-20 it is a lot more expensive. 

The other thing I would change is to use a Zilla Z1k-LV. For about the same price you can turn the motor amps all the way up to 1000 if you want. It will need a liquid cooling system as it isn't designed for air cooling (I have a simple cooling system on the one in my buggy.) If you choose the Soliton controller you won't have to buy a main contactor. There are pros and cons to each component choice.


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## Yabert (Feb 7, 2010)

ubersmart said:


> I see the Curtis controller used around here quite often. Other than it being "old" what's wrong with it?


A joke????

Curtis: Made sing motor at low speed, No build in contactor, poor continuous power capability, 500A peak, 72-144v input.

Soliton Jr: Highly programmable, Build in contactor, good continuous power, 600A peak, 9-300v input, Integrated fans and coolant loops, tack input to idle the motor at a constant speed, adjustable battery power (low Volt and Amps) and more.

I think you don't search a lot before thinking buy a Curtis.... Well, it your cash and your conversion! I just try to help.

And I agree with EVfun... Zilla can be a good choise too and your battery choise will give you under 50 peak hp and around 20-25 hp continuous.


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## ubersmart (Jan 3, 2012)

Ziggythewiz said:


> That doesn't give a whole lot of power with 40ah cells. I imagine even the curtis and warp9 could exceed that. Mine's a slug, but even it can get to 400, which is close to your burst.


Suggestions? Would it be OK to go this route now and plan on adding a second pack in parallel with the first at a later date? Or is this a "you'll fry your batteries if you try that"?


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## Ziggythewiz (May 16, 2010)

I wouldn't go lower than 60ah as a minimum, unless you plan to set the controller to strictly limit your power. 

That is possible though, I can keep my bug at 100A or less for anything under 40 mph without being much of a roadblock. Personally, I'd ditch the mini-BMS and go for higher cells.


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## ubersmart (Jan 3, 2012)

Thanks for the help. I'll ditch the Curtis controller. Since I need to find $$$ to pay for a larger battery pack I'm leaning towards building an Open Revolt controller or (preferably) finding one already built. Your thoughts?

Also, I made a request for quotations on alibaba and received a quote for these. I did a search here and couldn't find anyone who's used them. I'm very intrigued because they claim 5C continuous and 30C burst. I know you're going to kill me, but a pack of 40AH would potentially cost less than 60AH Calbs.  And, if nobody else here has used them I could be a pioneer.  (I suspect there's a good reason nobody here has used them.)


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## Duncan (Dec 8, 2008)

Hi Uber

Looks like an interesting find 
Buy a small number - test them - cut one up 
and let us know what you find out


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## EVfun (Mar 14, 2010)

They are an interesting find. I'm not aware of anyone using them in an EV at this time. Based on the internal resistance numbers for the 40 amp hour cell I would limit the discharge rate to 600 amps (15C.) Even at that point the cell would be barely above 2.5 volts. 

I have some reservations about the internal resistance numbers. It seems most LiFePO4 cell manufacturers measure it with an AC impedance test. The problem is that LiFePO4 batteries are built a lot like electrolytic capacitors and have significant capacitance. So using AC creates a result that is a lot less than the actual internal resistance measured with a DC load. My 60 amp hour Winston cells (late Thunder Sky LiFeYPO4 cells) where supposed to have an internal resistance (AC test) under 1 milliohm. The actual internal resistance is about 1.5 milliohms. 

I would encourage you to test a few cells. If you turn something up with significantly lower internal resistance you will be very popular.


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## ubersmart (Jan 3, 2012)

I've requested some samples.  Waiting for their reply.

On another front, I've just been informed that the Netgain motor won't be available until late March at the earliest.  However, that might turn out to be a blessing in disguise... I'll explain later.


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