Insulating Tongue Mounted Batteries for use in freezing weather

[TitanMike]

I have two 12 Volt batteries mounted on the tongue of my Micro-Lite. Installing them inside the TT is at this point NOT an option. I do plan on using my trailer in freezing weather as the bottom is enclosed and all three of my tanks have heat pads. I will also be adding the heating pads to the exposed portion of the Black/Gray tank discharge pipes as well as building a foam insulated cover to provide the same protection to them as those foam covers that one puts on the hose bibs on their house.

That leaves the batteries exposed to the cold. Batteries generate some heat when being charged as well as discharged. I believe that the available energy could be enhanced on a cold winter night if I could insulate the batteries from the cold and retain whatever heat that's generated by the current draw of the furnace, etc.

Has anyone built such an enclosure? I'm thinking of something fabricated from rigid foam insulation with foil vapor barrier attached such as what's sold at Home Depot, etc. Before jumping in I'd be interested if anyone else has been down this road before.

Naturally I would like to build something that can be removed during summer months as then I'd like to keep the batteries from overheating during charging.

Any experiences? Ideas? Pictures?

[youroo]

What about the batteries in the TV? Same weather and Temp! Youroo!!

[pilotpip]

Are you dry camping? If so, you may have bigger issues than battery temp. Heater elements draw a ton of amps.

We dry camp in winter, with a fully winterized camper for hunting (The outhouse seat is COLD!). Dual battery set up and the furnace will run all night with the blower on the batteries and no issues. Coldest overnight temp I've encountered was 15F. The most challenging item was the condensation. The vent fans in the ceiling and stove couldn't move enough air to keep the walls from having a bit of build up.

Otherwise, if you have good quality batteries, I wouldn't worry about it. They're designed for it.

[TitanMike]

Originally Posted by youroo

What about the batteries in the TV? Same weather and Temp! Youroo!!

I only need that battery to start the engine and never leave a draw on it. It's a "starting battery" designed to provide high cranking power at 0 degrees.

Deep cycle batteries have max capacity when electrolyte is 80 degrees. At zero degrees that same battery only has 50% of it's capacity even though it's technically fully charged. I'm just trying to get as much of that capacity loss as possible back by keeping the batteries from cooling as quickly as the air around them does.

When I lived in Colorado it wasn't unusual for temps to drop well under freezing at night and then be back in the reasonably comfortable range when the sun came out.

[WolfWhistle]

A fully discharged wet battery will freeze at 32 F, however a fully charged one will freeze at -76 F. Nuff said?
ww

[TitanMike]

Originally Posted by pilotpip

Are you dry camping? If so, you may have bigger issues than battery temp. Heater elements draw a ton of amps.

We dry camp in winter, with a fully winterized camper for hunting (The outhouse seat is COLD!). Dual battery set up and the furnace will run all night with the blower on the batteries and no issues. Coldest overnight temp I've encountered was 15F. The most challenging item was the condensation. The vent fans in the ceiling and stove couldn't move enough air to keep the walls from having a bit of build up.

Otherwise, if you have good quality batteries, I wouldn't worry about it. They're designed for it.

The insulation in my 2018 Micro Lite is one thing that seems to be well done. The furnace doesn't seem to run often when the temp's at freezing and it takes what seems to be forever to warm up even when in full sun and the outside temps are heading toward the 80 degree mark. Much to be said for the "foam sandwich" type of construction.

[TitanMike]

Originally Posted by WolfWhistle

A fully discharged wet battery will freeze at 32 F, however a fully charged one will freeze at -76 F. Nuff said?
ww

Not worried about freezing a battery, just want to be able to draw maximum energy out of it while cold outside.

This is a problem somewhat unique to TT's as MH's and 5-er's usually have batteries in a much warmer location than the tongue of a TT.

[WolfWhistle]

Oh. I have never heard of cold batteries being an issue in a trailer before, although I know a cold battery is far less efficient. The tongue box needs to be vented, assuming wet batteries, which would defeat the insulating method? If you are boondocking how do you plan to power heating pads? It would be easy enough to put a light bulb in the battery box, but would it be feasible energy wise... cost wise? Would it be better to add a 3rd battery? This is way above my pay grade.

[Bluepill]

I think the idea is sound. Just make sure to put some non-conductive tape over the foil face where it could contact the battery posts/wires.

[brianre]

Battery blankets that wrap around batteries, insulate and plug in to keep the batteries warm (120 volt plug ins) are available. As we live in a colder climates, we have two 6 volt batteries on our travel trailer, used in conditions down to freezing and the batteries made two nights running the furnace before charging required. We do not have any insulation on the batteries.

[mnoland30]

I use an RV battery for lighting my tent during December and February hunts in NM. I cut up a backpacking sleeping pad (about 3/8" thick) and placed pieces under and around the battery inside the battery box. It helps with the impact from rough roads too. The worst temps we've had were -20 degrees Fahrenheit. We did keep the battery box inside the tent, but the inside temp never got above 20 degrees for 3 days. Sure wish I'd brought the wood stove, but who would have expected -20 in southern NM? They grow palm trees not 40 miles from where we were camped. I use a portable solar panel to make sure that the battery gets charged up during the day. As already mentioned, a dead battery freezes at much higher temps.
At (–4°F) most batteries are at about 50 percent performance level, according to Battery University.