Everything in one really, really well insulated box.


New Member
Sep 6, 2023
Hi everyone, I have tried searching but have not found a answer. I have 400W of renogy panels, 40A renogy MPPT controler, LISUATELI 100Ah battery and a Canadian Tire modified sine inverter. Would it be a good idea to put everything in the same box for winter use along with the septic heater that Will mentioned on the winter heating thread. The cabin is on my home quarter, five minute drive to get too, but I don't want to mess around bringing the battery back and forth. We do use it pretty regularly in winter, but when we get a -30C cold snap not so much. I know dealing with lead acid is a different story, but I think a sealed LiFePO4 should be ok and apparently it does have low temp charging cutoff if my plans don't work out 🙄.

Thanks in advanced, and great forum too👍.
I will assume the inverter and batteries are not in the open, on the exterior wall, but in a room or shed, away from moisture from rain and snow.
In general, as long as the inverter is 24/7 online it will permanently generate heat enough to be safe from such low temperatures even in a cold room.
In your case in such cold envireonments there is always the risk of condensation due to extreme cold. Try to make a 8 inch thick polystiren enclosure and put it over the inverter and charger on the wall when not in use. Batteries however absolutely need protection, Lithium does not like the cold. Build a platform with at least 8 inch isolation under, and again 8 inch polystiren box around. Buy two PTC heaters, that you can conect to bateries to keep it above 0C/32F. Two 10w PTC heaters will be running about 2 days on a single battery. However if you keep your inverter on you can use bigger heaters and inverter is not gonna get that cold. Win-win.
I plan to use panels that are in the picture. They are R12 on thier own, but I will be doubling them up with a 8" spray foam in between them. This will probably have a foot thick walls when I am done lol. We don't leave the inverter on as it has a high idle draw(next thing to be upgraded). The nice thing about those panels are they are tin on both sides so it makes it really weather proof.
Right now all the equipment is outside in an un insulated ventilated box. I am more concerned about the safety of having the battery, inverter, and charge controller in one sealed box. If humidity does pose a problem, which I doubt it will as we are prettydry here in winter, I can always add desiccant to the box. The whole reason of putting everything in one box is to scavenge any heat that the inverter(when in use) and charge controller generates.