Since charge time occurs during the middle of the day when both ambient temperatures are higher, and sunlight is warming the enclosure, and since charging sligh

Since charge time occurs during the middle of the day when both ambient temperatures are higher, and sunlight is warming the enclosure, and since charging slightly warms cells, and since electronics also warm cells, you have a better chance of reaching the minimum low charge temperature. Maybe add some aerogel insulation? Also, active heating could work; requires a larger panel though. This solar-powered Pi project integrates a battery heater: https://hackaday.io/project/13260-lifepo4weredsolar1 https://hackaday.io/project/13260-lifepo4weredsolar1