More Pendleton Battery Woes

[jonjo1702]

Hi all
Just tried to recomission Pendleton Somerby but is seems the BMS has kicked in.
Battery is 36V 8.7Ah/313.2 Which I believe is a 9s configuration.
Getting 4.17V at each of the 9 pins on BMS connector ie 4.17, 8.34, 12.51 etc. Bike was stored over winter outside under cover and battery was left in....not good. I am guessing the battery is now toast as BMS will not send voltage to charge point to allow charging to kick in.
Any suggestions to try to wake it.
Have ordered a replacement, but this is only 2 years old. When switched on battery shows 100%, then drops back to 25%.

 

[cyclebuddy]

When switched on battery shows 100%, then drops back to 25%.

It's supposed to do that - 1 LED shows the battery is on, not state of charge. Quick press shows you battery charge level, 5 sec press shows the health (how many charge cycles it's undergone).

Any suggestions to try to wake it.

Press the power button for 3+ seconds. If that doesn't work, plug in the charger.

It's all in the manual.

 

[jonjo1702]

I understand about the battery status lights. Tried charging at least 50 times, charger flashes on red then constant green, what I am saying in the post......the BMS appears to have shut battery down as not allowing charger to start.

 

[jonjo1702]

It's supposed to do that - 1 LED shows the battery is on, not state of charge. Quick press shows you battery charge level, 5 sec press shows the health (how many charge cycles it's undergone).


Press the power button for 3+ seconds. If that doesn't work, plug in the charger.

It's all in the manual.

Hi cyclebuddy. I tried the simple hold the button in as per manual etc already, thats why I opened the battery and took readings of each cell bank. Seems as though BMS is holding off charging.

 

[Nealh]

It should be 10s , show us some pics of the BMS and wires.
You have likely missed out a cell group which might be low and the cause of the BMS not switching on.

 

[jonjo1702]

It should be 10s , show us some pics of the BMS and wires.
You have likely missed out a cell group which might be low and the cause of the BMS not switching on.

Hi Nealh, 9 cores on multi plug at top of BMS board all reading 4.17 to main neg , but there are ten groups of 4 batteries. I will upload some pictures later when I get home. Thanks.

 

[saneagle]

Hi Nealh, 9 cores on multi plug at top of BMS board, but there are ten groups of 4 batteries.

Listen to what Neal told you. You have a 10S battery. You have only found connection points for 9 of them. The last one is not on the multipin connector because it doesn't need to be. It can be between pin 1 and ground or the last pin and the battery positive.
The reason you cannot charge is either because all cells are full at 4.17v or the tenth group is below 2.5v. When you find which of the two it is, you will know where to find a solution to your problem : wake up the battery, or charge the low group.

 

[jonjo1702]

I am not disputing what Neal has replied, I can only report what I have found so far as I do not have the battery in front of me. I need to locate where to take a reading for 10th group like you say, as the nine pins to negative read 4.17, 8.34, 12.51, 16.68, 22.85...............37.53 V. I can then decide a way forward. Thanks.

 

[jonjo1702]

It should be 10s , show us some pics of the BMS and wires.
You have likely missed out a cell group which might be low and the cause of the BMS not switching on.

Hi Neal
Just got home and reopened the battery. Hope the photos are ok. Thanks for your help.

 

[Nealh]

#10 the missing group is the thick B+ Red wire.

The 29e is a pretty damn good cell though not a high power one but still a very good one especially in 5 or 6p format. It's depends on the BMS some won't allow switching even at 3v let alone the 2.5v d8ve has mentioned.

If all voltages are good then either the BMS is asleep or as mentioned by d8ve, the BMS won't allow charging as the battery is at approx. 98% .

One may be able to reset/wake up the BMS by disconnecting the 9 wire sense jst connector, then give it a min or two and reconnect it.

 

[Bikes4two]

Apologies for this question @jonjo1702 but have you actually tried fitting the battery back on the bike and seeing if you can ride under power?

If you can, ride around for a few miles to discharge the battery a bit and then see if the charger performs as expected.