diy solar

diy solar

"Double boiler" my Bluetti?

antoinette3173

New Member
Joined
Jan 19, 2021
Messages
8
I recently purchased a Bluetti EB240 (charging with solar panels) to power my off-grid security system. It was the best bang for my buck I could find for the power draw I'll have, short of building my own LiFePo system (which I'm working up the confidence to do). My issue is that the average low temperature on my land drops to 29 degrees (F) by November and doesn't get above freezing until at least April. Highs are no problem (53-89 degrees F all year). The Max Oak people tell me the Bluetti has a low temperature cutoff, but: 1) I don't know that I trust it. I don't want to blow a $1700 box by charging in cold temperatures because the cutoff failed; and 2) since it will be powering my security system, I would prefer to just keep the box from reaching low temperatures. I've been following the myriad heating pad + thermostat threads, but they all seem to be for DIY systems. I plan to store my EB240 in a box of some sort (pelican case? job box?) that will be at least partially buried, but not enough to neutralize the temperature impact. My question is: How can I best insulate the box holding the box (Bluetti), and is it safe or worthwhile to add heating pads to it, even though they'll be nowhere near the actual cells like they would be in a DIY system?
 
Dear @antoinette3173,
Hello ?

I think you are on a really good path from what you’ve said.

1) insulation : consider polyisocyanurate panels.
2) distance cells to pad : still worth it
3) use the type of pad that regulates itself. the kind for keeping liquid tank from freezing. not raw heater plus thermometer plus switch and controller. https://www.amazon.com/Upgrade-Version-Facon-Automatic-Thermostat/dp/B077VLB1KK on at 45F off at 68F perfect for LiFePO4 chemistry in my humble opinion (>32F requirement for charge). i bought that specific pad but i don’t have thorough test data yet.
4) the device itself will generate some heat. if you insulate it well enough then the heat from the inefficiency of the device will keep the cells above 32F. i still think it’s worth having a heating pad inside with the battery with insulation on outside. very efficiency yes wow.

hope this helps
 
Back
Top