I am working on a solar setup that is powered by a Li-ion batteries. However, Li-Ion batteries can't be charged below 0 deg C, and thus if it dies in the winter, it will need to be warm before it can begin charging. I will therefore need a heater for the batteries to bring them back up to temperature so that it can begin charging again.
I had 2 questions based on this -
- I had an idea run a Silicone heating pad (SKU TBD) that's directly connected to the solar panels (4x Renogy RSP100D-BK in series) so that the batteries can warm up and begin charging. Would the following make sense? -
- Assuming the above works, most commonly available silicone heaters are either 12VDC or 120VAC. Otherwise I can go a custom route. It's my understanding that these heaters don't actually care if the voltage is AC or DC, what's important is RMS? Do these heaters just work as and if the panel voltage fluctuates, I should be okay as long as I'm under the max voltage? If not, what voltage should I design the heater around - the combined open voltage of the panels is 97.2V or the optimal voltage of 81.2V? Power wise, should I spec something close to the max power of my panels @400W?
For reference the charge controller (SKU Renogy RNG-CTRL-RVR60).
Edit: I believe the following thermostat should allow me to control the heater, to turn on when too cold, and turn off when too hot.