Why 41ºF threshold for Victron Smart Battery Sense...

[spressomon]

Tried to register on Victron's Q&A site but its...broken.

Using Victron MPPT controllers and their Smart Battery Sense to stop charge current when the LiFePO4 battery pack is at or below freezing. But to utilize the pre-set perimeters for their MPPT controllers the low temperature cut-off defaults to 41ºF instead of 32, 33 or even maybe 34F.

Anyone have a clue why Victron chose 41ºF for the current flow cut-off?

 

[OllieChristopher]

Anyone have a clue why Victron chose 41ºF for the current flow cut-off?

Yes, it is to prevent damage to lithium batteries. Victron is using the standard low temperature safe charge of 41 degrees for lithium. The charge controller does not know what brand of lithium you are using so its default is set to error on the side of caution.

You can easily set your own parameters or disable the low temperature cutoff by going into settings and choosing "User Defined" next to your battery preset. You just want to make sure you match the manufacturers recommended range. For instance Battle Born Batteries can be safely charged down to 32 degrees and the internal BMS shuts down at 25 degrees no longer allowing the battery to accept a charge.

I do know the Smart Battery Sense died on me and was not worth the trouble. My Victron charge controller is close enough to the battery that the temperature readings are accurate.