Can anyone identify this BMS?

I have an custom built ebike I bought on Craigslist. Sadly I lost the previous owners contact info..
The bike would run perfectly for about 5 min then go dead..
48v system 1000watt front wheel hub drive.
Bike will show 53v when charging but goes dead after charger is unplugged.
This component is mounted at end of battery and has a series of green led lights that do not all appear to be lit some are also flickering. Leading me to believe this component could be failing.
There do not appear to be any discernible model numbers or brand names.. HELP!
And Thanks!!

got a little braver and carefully removed sheilding.. Looks like markings say "Skypower" and "1250" also I seem to have 16 wires running into this plug. Google isnt showing any boards that match this look... Anyone have any directions please?

Make sure it's not really bad first. It might just be doing its job.

Measure all the individual cell voltages to make sure you don't have one cell that's low and tripping the safety circuit.

I use some skinny solid core wires and poke them into the connector, but if you have access to the cells you can measure there too.

There are lots of generic replacements for a board like that. Best to get one with a matching connector so you don't have to rewire much.

The lights usually indicate taht cells are still balancing, so you should leave it on the charger until they all go green (or whatever color indicates finished).

Until then, there are cells that are not done charging, and if they are low enough the pack will not operate.

If there are 16 cells in series for the battery pack, and it's only getting to 53v, then if all cells *were* equal (they're not) they'd only be at 3.31v each. That's not fully charged for any chemistry. LiFePO4 would be 3.6V+, and 3.31V would be near middle of it's capacity range. Other types would be 4.1-4.2V, and 3.31V would be pretty close to empty.

So first, check the open-circuit voltage of teh charger (when it's plugged into wall but not battery). If it's zero that's probably ok, it just means it's a type that doesn't output until it's connected. Otherwise, post the voltage it shows.

Next, measure each cell voltage; you should come up with a list of 16 of them, and based on the 53v/16cells, most of them are probably in the range of 3.31v, some above and some below.


If you know what cell chemistry it is and post it here, it will help us help you troubleshoot it. SImilarly, if you know what the charger voltage *should* be, post that.

Any other details about the bike, including it's age, may also help.

How long has it been since the bike stopped working normally?

Did the problem start suddenly?

Did the problem gradually get worse?

How is the bike used? Gentle intermittent motor use with lots of pedalling? Full throttle fast use on hills with hard starts and stops and no pedalling? ???

Etc.