I saw a post this morning (which I cant find again now) which said that not all the LifePO4 batteries were the duck tape type sold on ebay.
I think Thundersky, Yesa and A123 were mentioned
Anyway I emailed Yesa for a price for 36v 15ah battery and charger, and they replied swiftly with a quote around $600
Anyway I have to say I was impressed with the picture, it was in a proper hard case and the charger looked well made too etc. It also seemed to have a bit higher max C discharge rate than the ones on ebay
Has anyone ever tried a Yesa LifePO4 battery?
Yesa Lifepo4
Thu, 01/08/2009 - 06:45
#1
Yesa Lifepo4
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heres the picture
I can't say about the yesa's other than we haven't had a lot of posted complaints. Most of the issues I have seen with lifepo4 fall into three categories. Failed or non existing bms leading to misuse. Duct tape sellers that use the little round 18650 cells. The little cells take about 150 to make a 20ah pack so invariably some cells have problems. Exaggerated claims for the c rate, or misundersood c rate leading buyers to purchase too small a pack. Then the high discharge rate damages the battery quicker than expected.
Take a hard look at lifepo4 sellers claims for discharge rates. Usually you only see test data for 1c discharge rates. A 3 c rated pack may not be so happy to do that continuously. Mr Ping, the best source of good duct tape style packs, uses a 3 c cell, but recomends discharge rates much less than that, usually 1.5 c.
He tells it like it is, but some sellers claim more than is realistic. Sure, my batteries can to 10c they say, but I don't tell you that the test was to 10% discharged. Discharge 10c to 90% discharge and you may kill the thing quick. In my opinion, buy lifepo4 in a size big enough to give you discharge rates in the 1.5 c or less and you will be happy. Buy a small pack, like 10 ah, and you will cook it sooner than you wanted.
Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global
yeh i use a yesa pack as a booster in my emax.
really good quality, with very little sag at load.
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
I asked for a discharge curve for this battery and Sam from Yesa sent me a 3C curve which looks good. He mentioned that the quality of their packs was better than many of the ebay ones. I think if I change to LifePO4 I will order from them.
Ive got some SLAs on my 36v electric motorbike. Ive used it everyday for the last 3 months and havent noticed much degredation in performance. I always top up after use and never fully drain.
How many cycles to SLAs generally last for if they are looked after