BMS Low Temp Testing Risk

[Rally375]

I have a Renogy 50 Ah lithium battery and want to test the low temp charge protection of the BMS, but I don't want to damage my battery in the process. I live in Maine and its below freezing pretty much every morning right now, so the test would just be to turn on my DC DC charger (I've got a switch on the ignition wire input) while the battery is below freezing and check that the DC DC charger senses whether or not the battery is connected. Does anyone know how quickly the damage/lithium plating will happen? I couldn't find much on the internet for it.

 

[grizzzman]

Put Battery outside. When cold enough test for voltage across the terminals.

 

[Rally375]

It can discharge down to -20 Celsius (not sure if that’s bms protected or not...) so I think it needs to “see” attempted charging to disconnect. Every frozen morning where it sat out all night its had no problem powering loads.

 

[grizzzman]

What amperage is your DC to DC charger?

 

[Rally375]

20 amps

 

[grizzzman]

You can charge below 0 C but at really low amps. Do you have something that would charge at say .5 amps?

 

[grizzzman]

That way if charging is not stopped by the BMS little harm would occur.

 

[Rally375]

Good point, I do have a limit option that would turn it down to about 2 amps.

 

[Deleted member 783]

Will tests them pretty hard in his videos. I don't think he would risk damaging all those batteries, so I assume a few seconds would be fine if it fails.

 

[grizzzman]

Good point, I do have a limit option that would turn it down to about 2 amps.

You must have the Renolgy dc to dc unit. That would much safer at 2 amps