For those interested; for each of my LFP280ah batteries I am using a pair of 120v (16w) heating pads. When tested earlier in the spring they worked well and increased the temp by about 10 deg in an hour as I monitored them. But there isn’t any temperature control. So for this I’ve decided to utilize the relay control that is available on the Victron BMV-712. Reasons why I liked this option was a) I can see with the Bluetooth app when the relay is closed or not (and heating is happening), b) I can remotely switch it on manually if I want (by inverting the relay in the settings), c) it will be simple to reconfigure it in the summer months to switch on a cooling fan rather than the heaters. For connecting this all up I connected the Victron relay signal from the back of the BMV-monitor to a solid state relay; (see photo) which then connects to a typical 120v receptacle. This is connected to a power strip which powers the heating pads. For an extra nice touch I also connected a bypass switch which will allow me to use the power strip for other things when the heaters aren’t plugged in. (like charging up our ebikes we carry in the cargo bay). I apologize for the poor circuit design but I don’t have any fancy software for that but it’s easy enough to understand how to connect it up. See the photos.
