My JK BMS is Superconducting

[Aloysius]

On the balance wire resistance readout cells 13 and 14 are illuminated in yellow and say 0 ohms and that bank is way out of balance at .1 difference.
cell 13 is the runner at .1 high and 14 right at the average. any one seen this problem?

 

[RCinFLA]

The balance sense wire resistance calculation can be influenced in both directions by poor cell to cell bus bar connections. Usually it is only done with near zero battery current to avoid this.

Each cell except lowest or highest cell has a bus bar in series with each balancing sense wire pair.

Sense wire is shared between two adjacent cells.

Inverter/charger current through bus bar and cell to cell connection can add or subtract what the BMS measures for cell voltage by the voltage drop of the high inverter/charger current through the cell to cell interconnect.

A good connection is typically in the 0.1 to 0.2 milliohm range but a poor connection can be much greater.

100 amps of inverter/charger current with a 0.15 milliohm cell to cell interconnect resistance amounts to +/-15 millivolts of error in the BMS cell voltage sensing.

 

[timselectric]

Bad connections.

 

[Aloysius]

these are Gotion modules the buss bars look good scared to tighten them much but ill try
the cell wires are not too accessible the second pic shows where 13 and 14 connect if this was poor wouldn't the resistance be greater?

 

[timselectric]

these are Gotion modules the buss bars look good scared to tighten them much but ill try
the cell wires are not too accessible the second pic shows where 13 and 14 connect if this was poor wouldn't the resistance be greater?

You can check for higher resistance connections with a digital meter.
There will be a voltage drop at the connection. This drop will be measured by the meter. (One lead on each side of the connection)
Test while putting a decent amount of current through the connection. (Charging or discharging)

 

[Wattson25]

I haven’t seen this exact issue, but it could be a faulty connection or a sensor glitch. Have you checked the wiring or tried recalibrating the BMS?

 

[Aloysius]

Im going to dismantle the plastic covers on the top cant access all the cells as is then i may rewire the balance leads without any plugs in the lines

 

[Aloysius]

Just looked at Aliexpress to get another bms and the price has almost doubled

 

[740GLE]

Where did those battery modules originally come from?

 

[timselectric]

No point in buying replacement parts, until you know what the issue is.
Troubleshooting, is the first step to repair an issue.

 

[Aloysius]

ReplyI got 6 of these Gotion 11 kw used modules for 3k about 2 years ago.they all tested 95 to 100% and have worked great
I got them from a company near fremont ca called posh Gotion is apparently one of the largest battery makers in the world
on the darkside I saw an article saying they where under investigation for using slave labor of the Weger people.
I want to get another bms so i can use it to test as well as another project ive started. ihave a feeling even if a trade deal is made these prices wont go back down as once they see they can sell at the higher price