Seeking advice my 24v overkill bms not charging because 1cell has low voltage, how do I charge just the one cell and get it working again ?

[YOTA]

I have a 24v overkill solar bms - 280amp eve cell pack . Was working great, but now one cell has dropped super low and the bms cut off & now won’t charge.

So now my whole system is off..

How can I charge just the one low cell ?

Or how can I get the bms to turn on and receive charge...

Can I just connect a 24v lithium charger to the battery’s and not use the bms.

Any suggestions truly appreciated

 

[butter_fry]

Use the app to override the BMS low cutoff voltages temporarily.

 

[YOTA]

I have a 24v overkill solar bms - 280amp eve cell pack . Was working great, but now one cell has dropped super low and the bms cut off & now won’t charge.

So now my whole system is off..

How can I charge just the one low cell ?

Or how can I get the bms to turn on and receive charge...

Can I just connect a 24v lithium charger to the battery’s and not use the bms.

Any suggestions truly appreciated

Does it mean I have to de-assemble my whole pack and pull out / charge the one dead battery ? Or is there another way around this.

 

[YOTA]

I have a 24v overkill solar bms - 280amp eve cell pack . Was working great, but now one cell has dropped super low and the bms cut off & now won’t charge.

So now my whole system is off..

How can I charge just the one low cell ?

Or how can I get the bms to turn on and receive charge...

Can I just connect a 24v lithium charger to the battery’s and not use the bms.

Any suggestions truly appreciated

Use the app to override the BMS low cutoff voltages temporarily.

Didn’t know that was possible how would I do this ?

 

[HRTKD]

You can connect a charger to just that one cell while it's still connected to the other cells. This is no different that the case where one cell is too high and you have to reduce the voltage from that one cell. Be careful to not overcharge.

Check your connections to ensure you don't have a poor connection that caused the battery to either read low or not get charged. If all your connections are good, it sounds like you might have a bad cell. Charging a bad cell can risky, so take it slow and check it frequently.

 

[mikefitz]

Check the cell low volt recovery setting In perameters . You could temporally set lower to allow recovery.
I don't understand why the charge path has been disabled.
If indeed a cell has dropped to a very low value, 2 volts or lower, its a failed cell or more common, a poor connection to the BMS leads or the cell buss bars.
The low cell protection values should be in the region of 2.500 volts protection and recovery 3.000 volts.

If the pack volts has fallen too low the BMS may not function correctly. I this case charge directly on the cells or pack with care and closely monitor cell and pack volts. Once you recover above protection levels charge as normal with the BMS in circuit.

What situation caused the shutdown?

 

[YOTA]

Check the cell low volt recovery setting In perameters . You could temporally set lower to allow recovery.
I don't understand why the charge path has been disabled.
If indeed a cell has dropped to a very low value, 2 volts or lower, its a failed cell or more common, a poor connection to the BMS leads or the cell buss bars.
The low cell protection values should be in the region of 2.500 volts protection and recovery 3.000 volts.

If the pack volts has fallen too low the BMS may not function correctly. I this case charge directly on the cells or pack with care and closely monitor cell and pack volts. Once you recover above protection levels charge as normal with the BMS in circuit.

What situation caused the shutdown?

Thanks for the advice..

You mean to charge the individual cell with like a desk power supply.

I was using my system quite heavily..
then suddenly after a few days it shutdown all togther.. I noticed one cell have low voltage rest were fine.. and then bms won’t go into charge mode. Doesn’t matter solar or using 240v power source into my all in one Growwatt inverter/charger/controller unit.

 

[YOTA]

Use the app to override the BMS low cutoff voltages temporarily.

My bms now won’t connect to my phone app: it’s been a while.. since I looked at this system.. I belive the bms had a blue light on when it’s working.. that correct ?

At the moment no light..

Is there a way to re-set it unplug plug back on ect.

 

[YOTA]

Thanks for the advice..

You mean to charge the individual cell with like a desk power supply.

I was using my system quite heavily..
then suddenly after a few days it shutdown all togther.. I noticed one cell have low voltage rest were fine.. and then bms won’t go into charge mode. Doesn’t matter solar or using 240v power source into my all in one Growwatt inverter/charger/controller unit.

Use the app to override the BMS low cutoff voltages temporarily.

My bms now won’t connect to my phone app: it’s been a while.. since I looked at this system.. I belive the bms should have a blue light on when it’s working..

At the moment no light..

Is there a way to re-set it unplug plug back on ect.

 

[YOTA]

Thanks for the advice..

You mean to charge the individual cell with like a desk power supply.

I was using my system quite heavily..
then suddenly after a few days it shutdown all togther.. I noticed one cell have low voltage rest were fine.. and then bms won’t go into charge mode. Doesn’t matter solar or using 240v power source into my all in one Growwatt inverter/charger/controller unit.

Could I charge the entire pack with a 24v lithium charger... (not using the bms, just direct to the battery terminals)

Or would I need like a desk charger power Suply to charge at a low voltage ect.

 

[HRTKD]

Could I charge the entire pack with a 24v lithium charger... (not using the bms, just direct to the battery terminals)

Or would I need like a desk charger power Suply to charge at a low voltage ect.

Yes, you can do that. But the cells that aren't at the low voltage will rise normally, possibly hitting and exceeding an upper limit you don't want to exceed. If you pay very close attention to the other good cells, it will work. But I wouldn't try to charge it very much. The safer approach is to charge the one cell and bring it closer to the other cells.

 

[YOTA]

Yes, you can do that. But the cells that aren't at the low voltage will rise normally, possibly hitting and exceeding an upper limit you don't want to exceed. If you pay very close attention to the other good cells, it will work. But I wouldn't try to charge it very much. The safer approach is to charge the one cell and bring it closer to the other cells.

Great thanks ?? - so I would need a special charger for the individual cell. Right ?

 

[YOTA]

Great thanks ?? - so I would need a special charger for the individual cell. Right ?

I have a red ark dcdc 1250D lithium charger I was thinking to connect up to this system..

Would I connect this straight to the battery terminals or to the bms.

The bms I would assume right ?

 

[YOTA]

But yeah I guess my bms isn’t letting any power through won’t turn on at all.. so trying to charge through my bms.. nothing will work. Other than charging the individual cell I guess or jump starting the whole pack ? I guess that’s why I though to charge the whole thing as a 24v pack with my 24v charger or direct from solar charge controller without my bus..

as yeah my blue tooth dongle won’t light up and no signs of life there. On app.

So I’m assuming my issue is the battery voltages are too low for bms to activate ?

Not sure what’s going on there..

 

[BenQ]

Care to share what battery cells make up your 24v battery? If you have access to the individual cells you should definitely try to charge the one that is low with a bench top power supply. You definitely don’t want to hook up your red ark dcdc 1250D lithium charger without a BMS inbetween unless you’re prepared to write off the battery bank.

 

[BenQ]

Or if you have a hobby charger hanging around you could use that! I bought something like this a long time ago when I was playing with 18650 cells and used it to top balance some LiFePo4 cells when I experimented with those

Hobby Fans B6 Mini Professional Balance Charger/Discharger with Power Supply for 1S-6S LiPo Lilon Life NiCd NiMh Pb RC Battery https://a.co/d/1bO8Fft

 

[mikefitz]

Measure the cell volts at the cell terminals and pack volts and examine all connetions. What is the voltage of the low cell?

The BMS should have entered discharge protection mode once the cell dropped below 2.500 volts but still allowed charge.

The BMS may have failed, or the cell has serious issues, more likely is an interconnection problem somewhere in the battery or BMS lead fault . Overkill have a comprehensive warranty on their products.
I understand from another post the battery has been left discharged for some time, how long?

 

[MrM1]

How did you set up the bms? In the app, did you chose a battery type, or custom settings?

If an overkill allowed one cell to drop so low it would permanently shut down the bms, it sounds like like u might not have the right settings in the bms

I might take these battery apart. Set all cells up in parallel, and using a desk top charger, set amps to max and volts to 3.65 ... BEFORE CONNECTING THE CHARGER ... and top balance the whole battery bank.

Go until voltage at the cell posts reaches 3.65 and current on the charger has dropped below 1 Amp

It will take a LONG time at your SOC.

 

[YOTA]

Care to share what battery cells make up your 24v battery? If you have access to the individual cells you should definitely try to charge the one that is low with a bench top power supply. You definitely don’t want to hook up your red ark dcdc 1250D lithium charger without a BMS inbetween unless you’re prepared to write off the battery bank.

Thanks for the reply, have ordered a desk top charger will try all this & see the outcome.

As for connecting the redark charge controller.

Can I simply connect it to the bms where my solar charge controller is connected.

Or will I need a seccond bms.

 

[YOTA]

Care to share what battery cells make up your 24v battery? If you have access to the individual cells you should definitely try to charge the one that is low with a bench top power supply. You definitely don’t want to hook up your red ark dcdc 1250D lithium charger without a BMS inbetween unless you’re prepared to write off the battery bank.

Have eve 280amp cells..

Can I simply charge the individual cells with the desktop charger.. without having to disconnect all the cells.