Chargery BMS16T harness melts while storage balancing

[solardad]

Mine run in balance mode constantly so the length of time is not the issue.

Disagree, I don't think you can rule out someone's experience with just your own. It was an issue for me and I have read others with similar experience where the mosfets overheat and the unit is 'too hot to handle' and/or shuts down (as it should). Common problem....? I don't know.

From what I can gather from the post there are potentially two issues:

1 - A bum cell which is being replaced by the vendor
2 - Unknown BMS issue. Unsure what the orig. poster will do but I would not use that BMS without a careful review and monitoring or just replace it.

They are very lucky to have caught the fire before it got out of hand. It is a good reminder that any component that is leveraged in a DIY system should be vetted and any issues understood. In this case just replacing the cell and calling it a day would not put me at ease.

 

[Craig]

Disagree, I don't think you can rule out someone's experience with just your own. It was an issue for me and I have read others with similar experience where the mosfets overheat and the unit is 'too hot to handle' and/or shuts down (as it should). Common problem....? I don't know.

From what I can gather from the post there are
potentially two issues:

1 - A bum cell which is being replaced by the vendor
2 - Unknown BMS issue. Unsure what the orig. poster will do but I would not use that BMS without a careful review and monitoring or just replace it.

They are very lucky to have caught the fire before it got out of hand. It is a good reminder that any component that is leveraged in a DIY system should be vetted and any issues understood. In this case just replacing the cell and calling it a day would not put me at ease.

Fair enough about my experience but what I want to know is why do/ did yours get hot and mine does not? Please I'm not disregarding your problem but as you say vetting the situation.

No matter what I think there is definitely a BMS or BMS connection issue. I'm not convinced the cell is bad though. Could it be? Absolutely. I would be willing to pay for shipping from Original Poster just to test it. If it is available.

Is your BMS available for testing as well? I would like to compare.

 

[Cal]

I think there's a good chance locating the initial hot spot within the BMS. Unless Chargery wants it back, it doesn't hurt to open it up.

This should be a warranty issue.

Been wondering how a balancer circuit is implemented. Is the balance current a constant 1.2A? Perhaps Chargery is using an op amp, fet and resistor to get a constant current? The fet in this circuit can get hot.

 

[BiduleOhm]

Been wondering how a balancer circuit is implemented. Is the balance current a constant 1.2A? Perhaps Chargery is using an op amp, fet and resistor to get a constant current? The fet in this circuit can get hot.

I don't think so, it would be too complex and costly. My guess is just a FET with a power resistor. The resistor value set the max current.

 

[cinergi]

FWIW I just observed my chargery doing some balancing ... the chargery itself got warm but the 24 AWG leads remained *cold* ...