BMS output low

3 replies [Last post]
Joined: 10/26/2011
Points: 7

I recently purchased a 48V 20AH lifepo4 battery pack from V-Power of Hong Kong. I was riding home from work yesterday, and the power cut out. I was only a block from home, so i pedaled home and charged the battery. Once the battery was charged, the power never came back on.

The BMS output wires measure 48.2V, though nominal voltage is about 57.0V
The charger port on the BMS still reads full nominal (57.0V) voltage.
The charging function still works on the BMS.
I still get full nominal voltage (57.0V) directly from the battery pack.

So i can run the bike by hooking up the battery pack directly, and using the BMS only for charging. However, i'm afraid i might damage the battery this way if i ask it for more amps than it wants to give. The max rated discharging amperage is 40A, and my motor/controller pull about 36A max, so on paper it looks like it will work, but i still want to ask.

My questions:
Will i damage the battery by bypassing the BMS?
What can i do to diagnose the BMS low output issue?
Or, should i just try to find a replacement for the BMS?



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scouttster's picture
Joined: 12/19/2011
Points: 14
Re: BMS output low

BMS is acronym for what? BMS means?

MEroller's picture
Joined: 09/26/2011
Points: 847
Re: BMS output low

scouttster wrote:

BMS is acronym for what? BMS means?

Battery Management System. In its ideal form it independently moniters the electrical health of every Lithium cell of a battery pack both during charging and discharging and makes sure not one cell is overcharged nor over-discharged and runs in perfect sync with all the other cells. This prolongs cell life and ideally also usefull range of a battery pack.


My rides:
QvR vR one: a Swiss package of pure understatement - innocent and to some eyes (from some angles) exceedingly ugly looks, but with raw and hardly containable electron power up to real 95 to 100km/h! And a literally rock-hard suspension due to a carrying capacity of twice it's unladen weight... Now converted to more controllable and efficient brushless motor and vector-contoller.

E-Sprit Fury (basis is the Erider Thunder 5000) since May 03, 2011. Highly moded - but now in active retirement

high voltage an...
high voltage and high discharge BMS system's picture
Joined: 12/16/2011
Points: 23
Re: BMS output low

I think you get a bad BMS system, their discharge current is not good, this is a very normal problem many users met, I am here hope you take a look on ,a real manufacturer and designer and supply a series of BMS from 2A to 200A, 3s to 30s BMS system, many famous ebikes company has cooperated with them for many years, for your reference, hope you like it, their email contact is ,good luck! Please don't go to a retailer or trade company to buy such bad BMS again, hope you enjoy it.

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