Our Lithium Battery and Cold Weather

[Steven@147]

Cold weather here in Galveston TX this morning, but not as bad as a lot of areas up north. It was 73 * F yesterday now this morning 36 * F real feel 21 * F and the wind howling, Burrrr!
Our Lithium battery is in the front storage compartment and the BMS shows 43.2 * F and shows protection Off. I guess that's not too bad of a battery temp with the ambient temps at 36F since our front storage is not heated. Our battery is not self heating. I don't think it would be a problem charging the battery until the temp of the battery approaches 32 * F

I hope that we would not be camping in even colder weather but that's not a guarantee so maybe I'll look into protecting the battery from cold for the future. Yeah I could have bought a Lithium battery that's self heated, but I didn't.
I guess I have a few options - easy to more complicated
1 -Leave it in the front storage compart and Stuff insulating material (microfiber towels, old T shirts ) around the battery.
2 -Cut a hole in the wall between passthru storage and front storage to allow heat to transfer into front storage
3 -Moving the battery to the passthru storage that is heated = major rearrangement of storage compartment.
4 -Leave it where its at and wrap a 12VDC heating blanket of some sort around the battery.
5 -Add some sort of AUX heater to the front storage compartment
6 -Add heat duct from furnace to the front storage compartment.

Currently the battery is in the front storage compartment, sets inside a plastic battery box screwed to the floor with a snap on lid and a strap around the box.

 

[triplethreat]

In my opinion, the easiest and fastest way....probably the cheapest too, would be to buy a small electric blanket, either 12VDC or 120VAC (if you can easily get 120V into the compartment with an extension cord. Maybe even consider an old style "heat lamp" bulb....just make sure that it's not going to overheat something and start a fire.

When I built my heated/insulated battery box a few years ago, I put in 28 watts of 12VDC Facon heat strips, controlled by a digital temperature controller. That controller has it's own temperature sensing bulb and I put that down in between two of the battery cells...with a spacer between the cells to keep from crushing the sensing bulb. It gives you a more accurate reading of the core temperatures of the battery cells than just laying on top of a cell or in the battery box. Good luck and I hope you get it worked out quickly. And BTW....yes, 43°F is a pretty safe temperature to charge the battery.

 

[Steven@147]

Tami said I could use some battery heated socks and stuff them around the battery.

 

[lineman1234]

Simple heating pad like one uses when one has a sore back or such. I havent used mine in 9 years i believe. Its in the bottom door of the bathroom.

 

[Soundsailor]

An old-fashioned incandescent light bulb might be enough if it's not too cold.

 

[jkwilson]

A friend uses 12V tank heater panels under his batteries in his boat. Not sure what their original purpose was.

A couple of things to keep in mind:

The temperature to be concerned with is battery temperature, not air temperature. This works to your advantage since using or charging the battery warms it. It works against you if you let the battery get cold since you have to warm the mass of the battery before it will let you charge.

If you use a heater under the battery, be sure to put some kind of insulator under the heater so it doesn’t waste heat warming the floor or outdoors.

Be sure you have a lighted switch or indicator to tell you the heater is on. Maybe even a thermostatic switch located a little away from the battery set above freezing a little.

 

[triplethreat]

A friend uses 12V tank heater panels under his batteries in his boat. Not sure what their original purpose was.

A couple of things to keep in mind:

The temperature to be concerned with is battery temperature, not air temperature. This works to your advantage since using or charging the battery warms it. It works against you if you let the battery get cold since you have to warm the mass of the battery before it will let you charge.

If you use a heater under the battery, be sure to put some kind of insulator under the heater so it doesn’t waste heat warming the floor or outdoors.

Be sure you have a lighted switch or indicator to tell you the heater is on. Maybe even a thermostatic switch located a little away from the battery set above freezing a little.

Facon tank/valve heaters....7 watts each and four of them, two on each side of the insulated battery box.

Those are controlled by a digital temperature controller in pic two....mounted on the back wall of the front compartment and it comes with it's own sensing bulb for temperature detection and control of the unit. It's the larger of the gray boxes and the controller is mounted inside that plastic work box.

 

[robmcqueen]

Are the batteries in a Battery box ? if so just lining the inside of the box with Reflectix insulation might be enough to keep them warm.

 

[Steven@147]

I got way too far ahead of myself in what I was thinking Vs what I was writing bringing you along. When I installed our Lithium battery I was curious as to how warm the front storage compartment would stay compared to the outside temp. Seeing as how our front storage compartment has no heat, no insulation, just metal floor and metal sides. Well last night/this morning I kind of found out. The outside air temp was 36 and the BMS was reporting the battery temp at 45.7. That's ok if I had needed to recharge the battery if the shore power had gone out. The battery is at 99-100% SOC. Of course you can use the battery and discharge it (if the shore power goes out) if the temp is down as low as -4 * F, you just can't recharge it until it gets above 32 * F.

Last night / this morning is supposed to be the coldest night. From today on the lowest it supposed to get will be 38-39 daytime highs up in the 50s 60s. That's ok for down here where we are now.

On the other hand if we stay up in the northern states during winter where it gets even colder I'll have to have a game plan to keep the battery warmer.
i'll work on that in the meantime. We really don't want to stay up north (IN, OH) during the winter but our kids/grands would like us to be up there for the holidays. This year we skipped out of town on them !

 

[lineman1234]

Are the batteries in a Battery box ? if so just lining the inside of the box with Reflectix insulation might be enough to keep them warm.

I always wondered if reflectix is conductive. Seems it is, i just tested a piece with the continuity meter on the volt meter.

The outside part might be made of the same stuff mylar balloons are made of. I have seen plenty of power outages because of the balloons as well as blown up equipment.
They loose air after being lost or let go, and land where its not a good place to land at times.

 

[ajg617]

@Steven@147 We have to BBs in the front but also the Genset which is open to the air for cooling. I took my temp monitor out on some cold days (teens) and measured the temps in the compartment early AM. Was surprised that they were as high as they were. I installed the heater wraps around the batteries since I did not plan on taking them out during the winter and we typically are in the single digits or teens at night during the winter. So far so good. I purchased the wraps from BB. They turned out to be generic which surprised me because BB charged about $250 each. But in three winters, haven't had to pull the batteries in front compartment yet.

 

[robmcqueen]

I always wondered if reflectix is conductive. Seems it is, i just tested a piece with the continuity meter on the volt meter.

The outside part might be made of the same stuff mylar balloons are made of. I have seen plenty of power outages because of the balloons as well as blown up equipment.
They loose air after being lost or let go, and land where its not a good place to land a

Good point. I have some in the garage along with a old battery. Curiosity is getting the best of me time for a science experiment. Will report back soon.

 

[Steven@147]

@Steven@147 We have to BBs in the front but also the Genset which is open to the air for cooling. I took my temp monitor out on some cold days (teens) and measured the temps in the compartment early AM. Was surprised that they were as high as they were. I installed the heater wraps around the batteries since I did not plan on taking them out during the winter and we typically are in the single digits or teens at night during the winter. So far so good. I purchased the wraps from BB. They turned out to be generic which surprised me because BB charged about $250 each. But in three winters, haven't had to pull the batteries in front compartment yet.

Was watching Will the Lithium battery guy and he was showing RV water pipe/tank heating pads and talking about using them. Guess that's another alternative.

 

[triplethreat]

Was watching Will the Lithium battery guy and he was showing RV water pipe/tank heating pads and talking about using them. Guess that's another alternative.

See my post #7 above ^^^^^^ That's exactly what I used, except the small one that I bought (7 watts each and 4 of them total) DO NOT have the built in thermo-sensing shutoff internal to them. That why I also bought and installed the digital temperature controller with its own temp. sensor probe that I put down and in between two of the cells.

 

[ajg617]

Was watching Will the Lithium battery guy and he was showing RV water pipe/tank heating pads and talking about using them. Guess that's another alternative.

I'm skeptical of the quality of the wraps. They don't go all the way around the battery and the sticky stuff doesn't hold enough at the ends so I'm going to duct tape the ends down. They worked so far though. There are probably better solutions - this was just convenience. I thought it was a dumb move to not get the batteries with the internal heater but the more I thought about it, that might have been a failure point. At least the wraps and sensor can be replaced without tossing the batteries. Probably are better solutions.

 

[lineman1234]

Good point. I have some in the garage along with a old battery. Curiosity is getting the best of me time for a science experiment. Will report back soon.

It was a quick test. It needed to be about an inch or so between probes to get the audio sound, but it still seems somewhat conductive, at a low voltage.

 

[Steven@147]

Facon tank/valve heaters....7 watts each and four of them, two on each side of the insulated battery box.

Those are controlled by a digital temperature controller in pic two....mounted on the back wall of the front compartment and it comes with it's own sensing bulb for temperature detection and control of the unit. It's the larger of the gray boxes and the controller is mounted inside that plastic work box.

I got them book marked

 

[TimtheToolMan]

Not having built in thermostat in heating pad/device eliminates chance of failing closed and possible fire risk. Likely best not to place battery on heating pad as this may increase chance of pad failure. Insulation can greatly reduce amount of heat needed but ensure that it takes little to no effort to remove--so insulation can be a trade-off. Want to allow batteries to have some cooling (they do generate some heat) when very hot out so insulation can reduce battery life/capacity over time.

I like the idea of having a backup on temperature control so that it takes two to fail to get stuck on. Snap disc thermostat (Senays site has more options) can be wired in series as a second line of defense. Two can be used to control temperature (not adjustable) or use one and Inkbird adjustable temperature controller that triplethreat mentioned. When using temperature controller use a snap disc rated above the maximum desirable temperature so that controller can control temperature.

 

[Steven@147]

As usual I've put together a rube/goldberg solution for heating our Lithium battery when needed, with the construction and cost being simple and economic. We do not intend to camp in sustained frigid temps so my solution is only for the few times the battery might get near 32 *F for the few times its needed, maybe just over night or for a couple nights. I Put together my solution from what others here on the forum have done and a couple Youtubes I saw. I don't think I'll need a whole lot of heating capacity just to keep the battery warm above 32 *.

I used a battery box for the new Lithium battery as listed in the parts. Now I know I don't have to put the Lithium battery inside a box but that's what I want to do for security and to protect the terminals from short circuits. Heck it was only $13. For me being fulltime and no plywood or boards stash, much easier than building a battery box out of wood and having leftover wood to do something with.

Here is a list of the stuff I got from Amazon.

Amazon.com

Buss Bars

Amazon.com

Insulation Pad

Amazon.com

Heating Pad

Amazon.com

Battery Box

Amazon.com

As an FYI, Fuse Block I got to protect the battery

The insulation that I'll wrap the battery with does have a conductive aluminum foil layer but as long as I keep it way down from the top of the battery and terminals I don't think it will be a problem. The heating pad I'll stick to the insulation wrap so it won't be directly stuck to the battery case.

The heating pad will probably only be along one side and maybe the ends of the battery, but not wrap all the way around it. All I need I think is a little heat along one side to keep the battery warm. The insulation heating pad wrap should fit around the battery ok and there is plenty of space in the battery box, should be easy to remove and slide the wrap off the battery if I have to take the battery out for some reason.

The heating pad draws very low power (@ 0.5 amp) but does not have an auto cut off thermostat. I'll connect the pad to the buss bars included in my list of parts. The buss bars I can also use for other 12VDC things we add to the RV like the new 12VDC compressor upgrade to the fridge. I'll connect the red power buss bar to the existing RV buss bar that's up in the front storage compartment by a short cable 6awg or greater.

For now I'll splice an ATO fuse holder with a 2 amp fuse on the heating pad power wire connected to the + buss bar and also use the fuse as a switch to turn the heating pad on and off. Won't use a thermostat for now, only put the fuse in when the temp of the battery is expected to get near 35 * according to the battery BMS. From my observation the ambient temp would have to get down into the low 20s * for the battery to get near 32 * F. I'll figure out a thermostatic cut off later, but even if I put one in, I'll yank the 2 amp fuse to shut the heating pad off.

OK now you can start chunking large heavy things at me for my crazy cheap solution !

As to why I just didn't buy a heated Lithium battery in the first place, I was watching Will Prowse and paraphrasing what He was saying, the heated Lithium battery option is expensive and maybe somewhat troublesome, and if you're not going to be utilizing the battery in very cold conditions consistently, why have it. So that is why I didn't buy a Lithium battery with heat option.

 

[robmcqueen]

Maybe wire the heating pads to the pos and ground on the trailer plug junction box that way if the batteries every get really cold and turn off you can plug into the truck to use the heaters. You could also put in a inline switch