Storing batteries in a northern Ontario winter
So my in-laws have a place in Northern Ontario that we visit for a month or two each Summer and that’s it for the entire year. I will be mounting 6 310 watt panels to the roof and I have built a custom rack that allows them to lay flat on the 2 pitch roof during the summer and tilt to a 45 degree angle when we leave. I have built a plywood panel that includes the combiner, charge controller, and breaker panel, that I would like to hang inside the cabin so I can easily see what’s going on with the CC throughout the day. This means I will need to stick my 12 batteries and inverter close by as well. My plan right now is to store them in a box that lays on the ground underneath the floor. Yes, I realize the batteries must be separated from the ground itself or they will drain to ground. My question is how much protection will they need from the potentially 20 below temperatures they will be exposed to during the winter? I found this article
which suggests using two layers of foil covered bubble wrap on the bottom and sides, just wondering if that will be enough. Also, I need to have ventilation in this battery box. During the winter, won’t that vent out any built up heat inside the box as well? Is this just a bad idea all together?