Daly BMS Reads wrong Cell Voltage

[Tylopoda]

Hello everyone, I hope Someone of you guys can help me.

I have installed a 12V system with a 280Ah LiFePo4 with 250A Daly 4s and 320wp Solar in my camper.
I'm currently in Norway and today while making breakfast the Daly BMS shut down.
Now the cell readings are:
4.999v cell 1
0.004v cell 2
3.002v cell 3
2.923v cell 4
I've measured all cell voltages manually at the sensor cable that goes into the Daly and they all are at 3.26v.

Have someone experienced something similar or know how to fix it?

Thanks in advance, Oliver

 

[BiduleOhm]

You very likely swapped two wires, probably the cell 1 + and cell 2 + ones (so wires 2 and 3 assuming the most negative one is wire 1).

Or the BMS has a defect.

 

[Tylopoda]

You very likely swapped two wires, probably the cell 1 + and cell 2 + ones (so wires 2 and 3 assuming the most negative one is wire 1).

Or the BMS has a defect.

That was also my first guess, but I haven’t change anything on the wires an the measurement via multimeter where also correct :/
Defect BMS could be possible but would be an showstopper for my trip

 

[BiduleOhm]

It could be a broken wire or a bad contact. Otherwise it's 100 % sure the BMS which is faulty, unfortunately.

 

[Rho]

Hello everyone, I hope Someone of you guys can help me.

I have installed a 12V system with a 280Ah LiFePo4 with 250A Daly 4s and 320wp Solar in my camper.
I'm currently in Norway and today while making breakfast the Daly BMS shut down.
Now the cell readings are:
4.999v cell 1
0.004v cell 2
3.002v cell 3
2.923v cell 4
I've measured all cell voltages manually at the sensor cable that goes into the Daly and they all are at 3.26v.

Have someone experienced something similar or know how to fix it?

Thanks in advance, Oliver

Had similar event. Check all the wires. I had a wire come off resulting in the readings you had. Hope this helps

 

[Rotgut]

For the future perhaps... My Daly 12V 4S BMS with 200ah LiFePO4 cells shut down because it was reading different voltages between cells (one low and the other high). A multimeter said they were the same voltage (3.318V from memory). I checked all connections and swapped the cells around, switching the "high" and "low" voltage cells and now the cell that was apparently high is now reading low and vice versa. I tried taking the BMS apart to check wire connections etc, but it is a sealed unit once you take the outer cooling plates off. All the wires and connections looked fine. Replacing the BMS with an identical one fixed the problem, even though I am using the same wires etc. For reliable long-term use of a battery it seems we had better have a spare BMS on hand (when offshore on a boat for instance) as there appears to be no way to fix a faulty BMS "on the go".

 

[Substrate]

You know this makes me wonder how many people experiencing balancing issues, have ever validated that the cell bms voltage with their own multimeter is actually right?

Your experience shows that it can vary and would be wise to doublecheck if one has the access.