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How about Hipower lifepo4 cells?

Posted: Wed Jul 08, 2009 6:51 pm
by evisfuture
Hey guys, does anyone has experence with Hipower lifepo4 cells? I got some test feedbacks of Hipower cell recently, it seems hipower cell’s performace is good. Hipower cells have less weight than TS cells. And recenlty they claim that their new cells can stand 3C continuous and 10C burst discharging rate. I am discussing with them to have a large quantity purchasing, hopefully we can get 1.05/ah or better. Any one is interested in it? They said they can offer 2 years warranty.


This page covers the decisions and choices made concerning batteries.
Which technology?
There was never really any doubt - it really had to be LiFePo's of some sort. Weight and life-time duration were the most critical duration, which rules out lead acid.

Since the choice also was made thinking about the motor - AC induction, running at 300V was the target - the pack had to give voltage and current - a small car really cannot handle the mass of lead acid batteries needed for that. It would have probably meant at least 250kg of batteries extra... too much (440kg instead of 170kg).

In the end, after about 3 months of enquiries, I settled on HiPower 50Ah units, using 95 of them to get 304V nominal. These will output (in theory, not managed this yet!) 2.5C to 3C current, so 150A - which is as much as the AC24LS motor can handle. And the price is right, and the guy dealing with this is straight and honest.

I've put the numbers in a spreadsheet, and in any case include it below as a graphic. Note that the pricing in Euro was correct when I put this together in the summer of 2008 - exchange rates have varied a lot since then! Prices are also what I would have paid, EU VAT (sales tax), import duty and delivery included. My purchase of HiPower was made in Sep 2008.
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Note that the packs are not all the same size - I have tried to configure what was possible for the vehicle. Consequently, I have made a few unit level comparisons:
• cost for 1500 cycles: lower is better, this is a real value in € (in fact the HiPower warranty is 2000 cycles/3yrs)
• power (Wh) per kg of pack, bigger is better
• power per buck (€1,000), bigger is better.
I've also estimated the charger cost (except for HiPower, that's the real cost) and I don't know all the warranty info: indeed most lead acids seem to have no warranty if you put them in EVs.

It's absolutely clear that the lifetime cost (based upon 1500 cycles) of HiPower is half that of lead acid, on the cycles which seem mostly reported by others or offered in the guarantee, and much better weight/performance ratio where only the MesDea seems to beat the HiPower (but look at the cost of the MesDea!).

On the kWh/€1000 - calculated on a 1500 cycle basis - the HiPower is 50% better than ThunderSky, over 3 times better than the LifeBatts, about 4 times better than the lead acids and 6 times better than the MesDea battery, which basically suffers from a poor guarantee (I have no real idea how long it lasts so maybe this figure is wrong, but even so...).

Clear to see that not just from a financial, ecological and mechanical basis, HiPower has to be the choice here (with ThunderSky 2nd). I plan 200 to 250 cycles per year (7,000 to 10,000km/yr), so 5 to 7 years of use is the current target. Only time will tell if this wasn't a good choice, but it certainly looks the best on paper and given what others have reported. It's the way I have chosen to go.


Hipower 10C rate cells
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evisfuture@gmail.com

Posted: Tue Jul 28, 2009 7:02 pm
by Tyc Track Uk Ltd
Hi Hope you dont mind have been reading your posting with interest our company Tyc Track Uk Ltd have representated Hi power in the Uk for over 12 months and supplied many applications in the Uk Italy and just recently Germany based on our cost profile on a landed to cilent basis, the rate per ah you mentioned we believe to be incorrect the price $1.05ah we can supply C & F at $1.5ah to your nearest Port Should your goodself or any fellow members have appications whether large or small we can hold this rate while the recession exists and are confident for these quality cells at this rate can not be beaten. Kind regards DAVE