For cold weather storage, the normal low storage temp. is +23F. Some will discharge at a temp. of -4F, but will destroy (or at least lower the life) of a LiFePO4 battery if charging below +32F. This limits usage as far as temperature parameters. The battery management systems will usually shut down the battery if the temp. gets within freezing range. I believe Relion has a model with a built in warming system that will allow charging at lower ambient temps. We have external lithiums (2x200AH) that have a built in warming system that allows charge/discharge in sub-0F temps. This is a Canadian product (KS2) which is proprietary to Roadtrek and available only through their dealers (Roadtrek will be under new ownership soon). It is optimal to have a programable voltage regulator set to specific levels at different stages of charging run through a second alternator (underwood generator) and a programmable solar controller. A few manufacturers have LiFEPO4 battery systems with batteries inside the coach for temperature reasons...space is sacrificed and cold weather storage could be an issue.
