In Sweden here a lifepo4 battery from chinese Topband ( no Battleborn available in Europe so far...We wait..) is sold with heat. But in that case it heats the battery first when a charger is applied using charge current. When above freezing then then BMS allows charge. In the cold, low light, cloudy, dark conditions as scandinavia during winter i belive there will be almost no charge in the battery with only solar. Just start heating and then it is dark again...But should be perfect for rv, caravan etc with dc/dc-charging. ( or if you use generator). Plug n play.