JBD SP04S034 BMS Low Temp Protection Factory Values

[MadMacks]

I just received a Jiabaida SP04S034 BMS with heat control, Bluetooth, and a few other options. I downloaded the factory spec sheet so I could better understand when the heat element attachment port gets triggered. The factory manual shows the following…




This makes no sense to me. My understanding is that LiFePO4 cells should not be charged at or below 0°c. Why would a manufacturer set factory defaults for triggering a heating element to the settings shown above? OBTW the columns are minimum, typical, max. So, for example, if I read this correctly they’re saying for a BMS without heating post the low temp protection can be set to between -15°c and -5°c and is typically set to -10°c, all of which are guaranteed to kill the cells! For my unit, which has a heat post I can apparently set the parameter to between -3°c and 3°c. Again, why would a BMS even allow you to set a low temp value below 0°c?

What am I missing?

 

[sunshine_eggo]

why would a BMS even allow you to set a low temp value below 0°c?

Yttrium doped LFP can be charged down to -20°C

 

[MadMacks]

Yttrium doped LFP can be charged down to -20°C

Ok. That’s nice if that’s what you have. But if you’re selling a BMS that can’t be set to above 0°c (according to the spec listed) then it’s really useless for anything but the cell type you mentioned. These are sold as LiFePO4 BMS units. I’ll load up the software and see if the range is really restricted to the listed values. I NEVER trust the temp readings on these cheaper BMS units are accurate so I ALWAYS set the cut off temp to around 3°c, or even a bit more…