Adding a heater to my lithium battery for winter travel

[Mitchell & Kitty]

On last year's winter trip down south to AZ, I ended up playing it safe and re-installed my factory lead acid battery until we were out of freezing weather. I did play around with plugging in a small 500 watt electric heater in the pass-through (where my Li batteries are) to keep it warm and that did seem to work pretty great in the evenings while plugged in at a campground. During travel days it still got cold though.

This year I will be doing something more direct though. I bought a packet of three 12 volt pipe elbow heaters ($45) and a cheap 12 volt thermo-controller ($20) on Amazon. The elbow heaters are attached to the sides of one big lithium battery. I taped the thermocouple to the side of the battery for the controller (under the white tape). This is just on my work bench right now. I'll install in the trailer just before leaving for the south. I'll probably add some insulation around the battery also. It looks like current draw from the battery is about 2 amps when heating. The other battery will stay unhooked until we hit AZ. This was actually a pretty straight forward and fun little project. Any suggestions from the brain trust to make it better?

[Yoda]

On last year's winter trip down south to AZ, I ended up playing it safe and re-installed my factory lead acid battery until we were out of freezing weather. I did play around with plugging in a small 500 watt electric heater in the pass-through (where my Li batteries are) to keep it warm and that did seem to work pretty great in the evenings while plugged in at a campground. During travel days it still got cold though.

This year I will be doing something more direct though. I bought a packet of three 12 volt pipe elbow heaters ($45) and a cheap 12 volt thermo-controller ($20) on Amazon. The elbow heaters are attached to the sides of one big lithium battery. I taped the thermocouple to the side of the battery for the controller (under the white tape). This is just on my work bench right now. I'll install in the trailer just before leaving for the south. I'll probably add some insulation around the battery also. It looks like current draw from the battery is about 2 amps when heating. The other battery will stay unhooked until we hit AZ. This was actually a pretty straight forward and fun little project. Any suggestions from the brain trust to make it better?

Nice project. Do you have a link for the controller?
Also on another site a guy used these heating pads https://www.amazon.com/gp/product/B0...JOE3FVDYM&th=1 and had his batterys in a cheep Styrofoam coolers.

Keith

[Mitchell & Kitty]

The controller is this: Amazon.com: bayite DC 12V Fahrenheit Digital Temperature Controller 10A 1 Relay with Sensor : Industrial & Scientific

It is fairly small and I only have to press 1 button to adjust the "off" temperature. I'll probably set it to 50F at the beginning.

I considered the bigger pads but I couldn't find one that fit under the battery very well without folding it up the side somehow. The elbow pads are just peel and stick and fit nicely.

[howson]

Any suggestions...to make it better?

While 2 amps is a relatively low amperage, are the pads and/or controller fused? I can't tell by the pictures the gauge of the wires, and didn't look up the maximum output potential of the controller, so a fuse might be ultra-conservative. (Makes me wonder if the tank heaters on newer GD trailers are fused?)

If a fuse is added, according to https://www.electricity-magnetism.or...ting-equation/ the rating should be the load current times a safety factor (they used 1.5). So a good starting point would be 2A x 1.5 = 3A fuse.

Howard

Edit: As a reference point, Therma Heat tank pads installation manual states, The connection must be fused with the correct amperage for their Pipe Elbow Heater Pad (model SL-E313). That model is rated at 13.5V @ 7.5W, so about .56 amps. (I had their manual in my stash of files...)

[Mitchell & Kitty]

I have a 4 amp blade fuse installed right now but will try to find a 3 amp. Thanks for the suggestion!

[TucsonJim]

I have a 4 amp blade fuse installed right now but will try to find a 3 amp. Thanks for the suggestion!

A four amp fuse will work fine in that application. Fuses are primarily specified to protect the wire in the circuit from excessive current. A typical DC circuit with 20AWG wire can be fused from 1 to 7 amps.

Jim