Options for keeping batteries warm? Comparison?

[ericfx1984]

So I have a solar shed and I'm looking at a few different options for keeping it warm...

It's insulated with r13 in the walls and are 13 in the ceiling... It has a really short ceiling maybe 6 and 1/2 ft? And it's five or six feet wide by 9 ft long

The first way that I tried to keep it warm was a radiator space heater set at 500 Watts.. This worked until it got down to about 20° and then I turned it up to a thousand Watts... And while it did work it used a surprising amount of energy... Typically I would go through 10 to 15 kilowatt hours on one cold evening

The second thing I tried worked a little too well... We were expecting negative temperatures... So I went ahead and put a buddy heater which runs off propane in the shed and left the electric radiator space heater as a backup... The results were pretty phenomenal... Even set on the lowest setting we saw temperatures as high as 107°... That's a bit much

Primarily I think the issue is that you can control gas flow... But not shut off based on temperature


The next option that comes to mind would be a diesel heater... I could easily install a five or even 10 gallon tank which in my experience on using diesel heaters for other things would easily run for anywhere from 1 to 3 weeks depending on the tank size


The other option would be heating pads... The problem I'm running into is that even with heating pads I won't get a particularly accurate reading of battery temperature as the leads coming off the BMS are fairly short... So the best thing I could do is maybe locate them at wherever the coldest place is on the battery... I suppose if I do this I would also want to enclose the shelf that they're in and wrap them in insulation

A couple notes... Well I do have r13 in the walls only two of the walls actually have a covering over them... Additionally the door doesn't seal up all that well and gets a bit of a draft... I'm thinking maybe I can correct those two things by putting up some sheetrock this week while it's warmer as well as adjusting the door so that it seals up nice and tight

Of these options? Which one would you recommend

 

[Crowz]

I voted heating pads and have used those for years. Works great.

I don't use them now because I put a heatpump in the workshop where the batteries are at. So I prefer the heatpump now but the heating pads are a no brainer one to go with otherwise.

 

[1201]

15kwh to heat an insulated 9x6 shed when it's 20 outside? Yeah, doesn't add up

 

[wheelman55]

Are these Lithium batteries? On a rack, on a shelf on the floor? Send a picture of your batteries in the shed. It’ll give commenters something more conducive to giving helpful comments

 

[dopeassjackson]

What kind of batteries? Either way if your trying to keep something warm air sealing is important and R13 batt insulation isnt really that much. How much insulation in the floor. Floor insulation really matters also because I bet your batteries are near the floor and that's where the cold stays.

 

[Chicat]

I use automobile battery wraps that only use 60 watts. They do get very hot if you leave them on, so I have 2 set up on individual timers at 30 minute intervals.
I also use these in our water storage building to keep pipes from freezing

Kat's - 22100X 22100 60 Watt 28" Battery Thermal Wrap​

 

[ericfx1984]

15kwh to heat an insulated 9x6 shed when it's 20 outside? Yeah, doesn't add up

Yeah that's what I thought... But it's happened multiple times

 

[ericfx1984]

I use automobile battery wraps that only use 60 watts. They do get very hot if you leave them on, so I have 2 set up on individual timers at 30 minute intervals.
I also use these in our water storage building to keep pipes from freezing

Kat's - 22100X 22100 60 Watt 28" Battery Thermal Wrap​

Do these just turn on at a certain temperature? Or do you need a controller?

 

[CVCPJared]

R13 isn't R13 if there's no barrier to keep air from moving in and out of it. Sealing that up air tight might drop most of your heating needs

 

[Crowz]

Do these just turn on at a certain temperature? Or do you need a controller?

Amazon.com

$21




I use this controller and heating pads from amazon to heat batteries and my water pipes. Works great at both jobs

 

[Chicat]

Do these just turn on at a certain temperature? Or do you need a controller?

No, they are either on or off, that is why I use the timers

 

[Todhend]

mine are on the completely covered enclosed porch, I use pet heating pads, each 4 batteries sets on a pad and using solar to power, they have a high and low setting and so far work fine, I haven't calculated the cost on high when very cold

 

[OM617YOTA]

Think sleeping bag, not room heat. The less space you need to heat, the less energy you need.

I put my batteries in a box barely larger than the batteries, insulated with 4" of foam insulation board on all sides, including the bottom. A couple stick-on heating pads are on a piece of aluminum tubing between the batteries, with a small air gap, used to moderate temps from the heating pads and have more air contact area. No direct heater contact to the batteries. A cheap baseboard heater thermostat controls them and they run on direct battery voltage. Lots of thermal mass in the batteries, small heated volume, decently insulated. Only ~19w of heat, but with the insulation that's been plenty, it's had no trouble keeping the batteries at 50F even when 15F outside. No clue how many kwh it burns, not enough that it's been a problem. I'm in the PNW of the USA and at the beginning of winter we had 3 WEEKS of freezing fog and *zero* solar harvesting that entire time. Battery heat still wasn't a problem.

 

[1201]

Yeah that's what I thought... But it's happened multiple times

Are you trying to heat the space to 80 degrees? You just need to heat it to above freezing. Most plug in type controllers shut off at 45 degrees.

 

[ericfx1984]

Are you trying to heat the space to 80 degrees? You just need to heat it to above freezing. Most plug in type controllers shut off at 45 degrees.

No. But the propane buddy heater on low WILL heat to 100F or more weather I want to or not

 

[davros]

R13 on two walls is total R0 or close to it. It is like leaving your fridge door open 24hr a day .Ceiling should be double R of walls

 

[BigGun]

I use Reptile heating bulbs ( 4/ 100 watt ceramic ) in my 6x6x6 Well Pump shed only insulated in the ceiling on a slab. They are connected 2 on one thermostat set at 46 degrees and 2 on another thermostat set at 40 degrees . I've have seen temps go down to 8 degrees outside and inside my pump shed never got below 40 degrees. I find they work much better if you don't set the temp too low. When the weather is only around freezing, most of the time the second set don't come on. My setup has WiFi camera and Thermometer to keep track of this. ( My camp setup, I don't live there)

 

[JAS]

What if you leave the Little Buddy heater on pilot (instead of low)? Sometimes, that is enough. Especially, if you can seal up the rest of the shed better.

 

[dopeassjackson]

Amazon.com

$21

View attachment 280157


I use this controller and heating pads from amazon to heat batteries and my water pipes. Works great at both jobs

I used one of these STC-1000 controllers before on baby chicks. You can really dial in the temp. Bi was running a 500w heating lamp. They make them for AC and DC along with different voltages too.

 

[50ShadesOfDirt]

Another option is a propane wall-mount heater *with a thermostat* (you can find these new for $200, or sometimes used for much less), and a 40-lb tank outside the wall.

Set just above pilot, it will keep the inside of shed near 50 degrees, or you can dial in your desired temp. Our LiFePO4 batteries are at mid-height, but you can also run a small usb or 12v fan, and "circulate" the heat. Tank lasts weeks (our "utilities" shed has insulated walls/ceiling), and we refill from our site propane tank (with a "wet leg").

We are at 7000+ feet, and temps get to zero or below. No problems keeping the solar gear, batteries, water tank, pumps, etc. in good shape.

 

[SunSurge]

We are considering a solar shed as well and looking at maybe using a diesel heater during extreme conditions like the -23C (-10F) we experienced recently. Our Ruixu-Lithi2-16 batteries have been in our house since Dec/Jan and will be until we construct a structure and are ready to install sometime this spring. Below is information from the Ruixu manual regarding working/storage temperatures. It appears that these batteries should not be exposed to extreme cold temperatures.

The manual says the battery should be placed in a dry, clean, dark, and well-ventilated indoor environment for long-term storage, and the recommended storage temperature range is 15~30℃ (59-86F). If not used for a long time, the battery needs to be charged every 6 months.

The Seller has no obligation under this limited warranty for product subjected to the following
conditions (including but not limited to):
.
.
Environmental damage such as inappropriate storage conditions as defined by the Manufacturer,
exposure to extreme hot or cold temperatures, fire or freezing, or water damage, impact, or
collision

Storage temperature

0℃<T<30℃ < 6 months
-10℃<T<45℃ < 3 months

Working temperature

-10℃-50℃(maximum operating range)

Recommended environment 15~35℃, 5~75%RH

 

[1201]

No. But the propane buddy heater on low WILL heat to 100F or more weather I want to or not

Then it shouldn't be using near that much energy.

Maybe there is a huge air leak?

 

[ericfx1984]

R13 on two walls is total R0 or close to it. It is like leaving your fridge door open 24hr a day .Ceiling should be double R of walls

Yes in practicality it should be double... But it wasn't feasible to do that

 

[AH Trimble]

Look into waterproof seedling mats. They are temperature thermostat controlled and use about 20W.
Another option are reptile heating mats, similar to seedling mats.

 

[ericfx1984]

R13 on two walls is total R0 or close to it. It is like leaving your fridge door open 24hr a day .Ceiling should be double R of walls

R13 in ALL walls and ceiling... Only 2 out of 4 walls has sheetrock