BMS not allowing charging on 24 cell Bolt battery

Long post - sorry
So I spent 5 hours yesterday troubleshooting a charging issue.

I installed the four additional Bolt battery cells that @grantwest sent me. I now have a 24S Bolt pack in my e4 (Ha ha, your not the only one now @grantwest ). Runs great.

Hooked up the BMS (its the Chinese one) to the additional four cells and the BMS is showing all cells, voltage, and current when driving.

Switched the profile on the Delta-Q to #177 - all good.

Hooked charger up to the old charger connections, Neg on the Neg controller and positive on the main positive battery lead. Same locations as before with the 20S configuration. Interlock is bypassed and charge enable (white) is grounded.

Plug in the charger and I get six red flashes after boot. Dead…

I tried everything including three different chargers and all kinds of different charger connection points.
All the same - Charger boots then six red flashes.

Finally - I hooked the charger pos and neg directly to the battery pos and neg.
Charger booted and started charging. Success!!! but why?

Moved the pos charger cable back to the original location under dash - Charger still works.
Moved the neg to the input of the BMS - Charger dead.

It appears the BMS is not allowing the charger to see the battery correctly, however, everything looks fine in the BMS. Both the LED screen and in the Bluetooth application all looks fine. Charge is enabled on the BMS. The charger just does not like it anymore.

@Inwo - any idea’s here? This is the same BMS you original installed on the GEM. Have you seen anything like this before? It has me stumped, adding four cells should not have changed anything.

Thanks in advance,

I’m no expert with your BMS but it seems like from your explanation that the Charge controll wire or port comming off your BMS is dead.

I had a BMS go bad in that port. Dave was able to fix that port.

Have all the settings been change to a 24s system?
String number?
Total voltages?
Total low voltage?

Strings - Yes
Total Voltage and total low voltage I thought updated automatically when you changed the string number? so I have not changed them. I will take a look at those tonight. If it is that simple I am going to be really pissed at myself :slight_smile:

Yes, should be. This bms is totally under user control. Which is great, but all the settings must be changed to fit the battery.
Depending on app, the charger mosfet (tube) is shown top of screen.
Open/closed is bass-ackwards, on some. Open means on. Like a valve, I guess. An open switch is off!

David the master has done it again -
Total voltage was still set at 86 and it needed to be 99 with the four extra cells, I changed it, It will be later in the week before I can test the charger again but I am sure that was it.

Thank you again