Originally Posted by Rhumblefish
I moved my LiFePo batteries into conditioned space and further back on the tongue. (Moving to LiFePo was easy choice: more capacity, less temperature sensitivity, no venting required, lighter than lead acid AND further back in the coach (but ahead of the axle(s) plus all the other benefits of LiFePo over lead acid, even $ in the long run). Using a tankwarming pad seems odd as (1) it'd be self-consuming and (2) you already are heating a space (of which the battery could take advantage). Just my .02.
Tank warming pads would typically only be turned on prior to charging. LiFePo4 batteries can be discharged down to below zero, it's only charging that is the issue.
BMS will prevent charging (on good LiFePo4 batteries) until temp is above freezing. Turn on heating pad, start generator, and when batteries warm enough actual charging will commence. The heating process is powered by the charging source.
This of course would only be necessary if bateries are in unheated space.