S series controllers and P5 parameter

[Deleted member 4366]

There's two possibilities then: Faulty cells or faulty BMS. I would estimate that you should be able to do at least 20 miles before your battery indicator shows half-full.

You should collect some exact data from your wattmeter: How many aH does your battery give before cut-out; what is the voltage at that point. If what you've told me is correct, there must be a faulty cell or connection in the battery.

Collect the information and pass it to BMSB. Keep it simple:" my 36v 20aH battery from order #xxxxx cuts out at 38v after giving only ??aH. What should I do?"

Do diagnose further, you have to open the battery to get to the BMS multi-pin connector, but you need to inform BMSB first otherwise they can blame you.

Is there any damage to the corners of the battery?

It looks something like this inside depending on whether you got the long thin one or short fat one. This is the short fat one:

 

[Alan Quay]

Thanks for your help. I will conduct some test and report back in a bit.

 

[Alan Quay]

Ok, I have done some testing, and its a faulty battery. Tried the bike with two other identical batts, and no cutouts.

I have emailed BMS battery, but I'm not getting very far. They keep getting the wrong end of the stick.

So it looks like my only option is to open it up.

It seems to cut out after giving about 2ah, at which point the voltage won't have dropped much, as the display shows full capacity (implying not much drop in volts).

If it a faulty cell/BMS, is it possible get hold of the parts easy enough?

 

[Deleted member 4366]

If it were mine, I'd go for a ride until it starts cutting out. Then, before charging, rip the battery open to check the cell voltages at the multi-pin connector. If they're all OK, I'd then temporarily bypass the BMS by connecting the output negative wire to "B -" pad. Then see what happens. If it works OK like that. it would imply a faulty BMS. You then have a choice: Replace the BMS, or leave it like that. If you have a wattmeter permanently connected, you can use that to limit pack voltage.

 

[Alan Quay]

Ok, when it stops raining I will do just that and report back. I might do it in a new thread, as the tittle of this one is now a bit misleading.

Thanks for your help.