My DIY heat pad setup for my Lipo Bank

[ywhic]

I decided after some research (on here and other places) and before winter gets here to come up with a battery heat pad setup for my new 3x 100ah Lipo4 batteries that are in my aluminum tongue box on my enclosed trailer/camper conversion. This is so I can charge up on colder/cooler days and not have the BMS get tripped by the less than the built-in 32'F settings.

These came with 1" thick packing sleeves (shown in picture) that the batteries slide down into. These were just tested with a 2x 15w series of heat pads to check for any burning or anything and passed with 0 issues. Its not a normal "styrofoam" I guess.



I have attached 2x15w 12v pads in series on aluminum foil "pans" from the dollar store to spread the heat out across the battery area. These cover over 8" in width (of the 9" long batteries) and go up 6"+ of height. I will be using 2 heat pads per side in series and 2 pan pieces as shown with some 10'C (50'F) thermistor relay/switches on each series mounted on top of each battery. I will be trimming down the excess wire upon install.

I also have the Victron battery/temp sensor on the bank in the middle to monitor things and will be adding a few extra wireless outdoor thermometers to keep an "eye" on things.

So these 2 "pans" will sandwich the battery on the "long" sides.



Also in the camper/enclosed trailer will be 3 small LED's that will be wire into this (1 per battery). So when the switch/relay closes it will complete the circuit and light the LED so I can see that the circuit is active/live and when it releases and disconnects when the temperature gets back above the cutoff.

I created a small scale version using an 7ah SLA battery I had laying about and it kicked on pretty quick in the freezer and kicked off when removed from freezer in less than 2 minutes into room temperature.

I prefer 50'F(10'C) on/off vs. the "normal" 35-41'F settings I see because my luck would have something not work and it would be freezing out.



I am just waiting on the LEDs to come in and some decent not raining weather to do this.

I do plan on insulating the recessed lid of the tongue box and using the included "foam" packing that was on top when shipped to close up the batteries some for the winter.

Top "packing" even has cutouts for the terminals. should help keep the top "warm"



I will post more pics and things as I do them up next week.

Thoughts or suggestions??

 

[ywhic]

Better picture to show the setup.

2x 15w pads per side panel in series. Then both sides thru just 1 of the 10'C (50'F) 10 amp rated thermistors, onto the LED leads, then the battery buss bar. Upon the relay/switch kicking on, the LED's will light up and the heat pads will get hot.

I don't have a clamp meter and my current meter needs the current fuse replaced apparently, that or this is drawing less than it can read possibly. I will try and sort that out also and get some numbers on these 15w pads in series draw for you's.

Will be trimming down the series silicone wires upon installation to clean up.

 

[Andrewr05]

Nice write up

I really gotta get my camp cabin setup done too, it's already gotten down to the mid 40⁰s at night here in New Hampshire.

 

[ywhic]

I finished all 3 sets tonight, be installing them tomorrow after doing laundry in the morning.

Be grabbing 3 independent temp sensors with readout displays from Amzn to watch them, inside temp, and outside temp. They are like 5x for $12 or something.

Also the Victron battery/temp sensor will be located on the middle battery of the 3 as well.

 

[ywhic]

The battery packing top part. Has cutout for display. Hopefully I can keep the 1" top part thickness in tact, which matches the 1" side and bottom thicknesses. That will help insulate in case the BMS is on top (I heard most are).

Of course I will need to notch the top for the parallel cabling. But that should be minimal.

 

[ywhic]

Sample of 1 battery in the sandwich.

Was able to slip my pan/pads down the sides of each battery without too much trouble. Total of 4x 15w pads per battery. 2 in series per "long" side, then paralleled before the thermistor/relay/switch.

I DO plan on trimming back the top part near the buss-bar and wiring so no worries.

Should I block the meter built in the battery to further keep in come winter or leave open to view if need be??

I was thinking removable "foam plug" for winter, and remove the top and plug come spring. ??

Thoughts??

 

[ywhic]

Covers on mock up. Displays showing. And then when I put the "plugs" in to cover the displays.