LiFePO4 bikes w/o BMS... what experience do we have?

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reikiman
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LiFePO4 bikes w/o BMS... what experience do we have?

When I first heard of X-treme's plan to sell LiFePO4 bikes w/o BMS's I shook my head in disbelief. But there are several on V who bought those bikes and here's one person chiming in a year later saying "not a problem".

xb-700li 1 year later

It seems therefore this group has some experience we can share about using LiFePO4 in real world situations. A few questions that come to mind are

  • What precaution exists on X-treme's bikes for undervoltage? I assume overvoltage precaution is done by the charger.
  • Have any of the owners monitored back balance? Observations?
  • Have any of the owners added BMS systems?
scootoregon
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Re: LiFePO4 bikes w/o BMS... what experience do we have?

I have had my 700 Li for over a year as well. The one major problem I have had has been documented here on this forum. I am currently riding again, with a replacement pack from Xtreme. I believe the problem I had was that I discharged the pack low enough to reach the LVC and then the charging board circuitry malfunctioned. At least that is the gist of the response from Xtreme.

As far as not having a BMS on the scooter. I have not seen any ill effects. My riding style is to keep the throttle wide open and I never saw a drop in performance for the whole first nine months. Of course after that the circuit board fiasco ensued.

As of now, I have put about 85 miles on it since I received the new pack and it is running exactly like it used to. We are currently in a cold snap here and you gotta love the Life Po batteries. No sag whatsoever. So I guess my advice to other owners would be to not to let your pack get to the Low Voltage Cutoff point and you shouldn't have the issues I ran into.

Happy scooting, Scott.

decibel1
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Re: LiFePO4 bikes w/o BMS... what experience do we have?

I'm currently running an electric bike with a 1000W Goldenmotor (China) system purchased on Ebay and a 48V 20AH Thundersky LiFePo4 pack from Elite systems without a BMS. The Battery pack consists of four 12V packs each assembled from 4 20AH Thundersky batteries put together in the same package (This is how they come when purchased). After 1,000 miles, everything seems fine, but I can only check the 12V modules for balance and they are quite close to each other. Checking the individual cells would require breaking open the package containing the cells, which I don't want to do.

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