Basic question: "When does balancing start?"

Fredrik_Viberg · 2022-01-06T15:36:22.842Z

Hi, I have a basic question. Under what conditions does the cell module start balancing the cells?

I have discharged one cell in my battery pack to be about 0.5 v below the other cells. Now I sort of expected the other cells modules would try to lower their voltage to match the lowest cell.

Do I need a bigger voltage difference? or is it only during charging the balancing starts?
Have been trying to read the code to finger this out, but it is a lot and maybe asking is quicker .

atanisoft · 2022-01-06T18:26:24.548Z

Fredrik_Viberg:

Now I sort of expected the other cells modules would try to lower their voltage to match the lowest cell.

I believe each module is treated individually with no knowledge of neighboring modules. If any one module crosses the lower threshold that the controller is configured to use it will trigger a rule, similarly it any cross the high threshold.

I’m not aware of any interactions between modules when there is a major imbalance between them.

Fredrik_Viberg · 2022-01-06T19:38:33.975Z

Pretty sure the modules can balance the cell voltage, just not sure yet under what condition it starts. I can update this page when I have figured it out.

atanisoft · 2022-01-06T20:01:54.857Z

Fredrik_Viberg:

Pretty sure the modules can balance the cell voltage, just not sure yet under what condition it starts

If the module detects the connected cells to be above the given threshold it will enable the resistor bank to dump excess from the cells, it will not transfer the excess to another module/cell though.

If the temperature of the module PCB goes above the threshold it will reduce the time that the resistor bank is enabled.

Fredrik_Viberg · 2022-01-06T21:38:09.431Z

aa thanks, now I understand, so the modules only “top” balances.
Do you know how much watts the resistor bank can dissipate?

atanisoft · 2022-01-06T21:47:40.960Z

The load is up to ~1Amp when the resistor bank is fully enabled (ie: always on, temperature below threshold)