LifePO4 and temperatures specifically COLD and FREEZING

[Biggkidd]

One of the biggest problems with using LifePO4 cells in an unheated power shed is temperature stability. More from the cold than the heat in my climate, although heat can also be a problem. A few months ago I got nearly 600AH of cells at 51.2 volts (48 volt system) I've been dragging my feet on hooking them up because they can be stored at cooler temps but they can NOT be charged below freezing. Well of course we are in the coldest Jan. in years right now as I am contemplating how to keep my new batteries from freezing when I do hook them up. Then a couple days ago I had the thought to use water pipe tape / cable that turns on at 38f and off 50f.

So I thought I'd post about here incase anyone is having the same or similar issues.

 

[Neb]

One of the biggest problems with using LifePO4 cells in an unheated power shed is temperature stability. More from the cold than the heat in my climate, although heat can also be a problem. A few months ago I got nearly 600AH of cells at 51.2 volts (48 volt system) I've been dragging my feet on hooking them up because they can be stored at cooler temps but they can NOT be charged below freezing. Well of course we are in the coldest Jan. in years right now as I am contemplating how to keep my new batteries from freezing when I do hook them up. Then a couple days ago I had the thought to use water pipe tape / cable that turns on at 38f and off 50f.

So I thought I'd post about here incase anyone is having the same or similar issues.

In winter yes if too have the power to spare.

In summer we don't want to diminish the ability to dissipate heat.

Ben

 

[Mountain trapper]

My battery bank is lead acid so I don't need to heat the building. But I do need to keep my pump house above freezing. The pump house is 8×8 and well insulated. I installed a wall mount propane heater with thermostat and plumbed to a 500 gallon tank. I keep it on the lowest setting and it'll keep the pump house at least 45 degs in below zero outside temperatures.

 

[Biggkidd]

My power shed is 6x8x8 and uninsulated T-111.

 

[Hardcalibres]

My power shed is 6x8x8 and uninsulated T-111.

It will always be more efficient to just heat/insulate the batteries than to try to heat a bigger space/mass like a shed.

 

[Mountain trapper]

My power shed is 6x8x8 and uninsulated T1-11.

I used T1-11 also on my pump house. I put rolled insulation between the studs and then put 2" insulating boards for the ceiling and on the walls. Except on the coldest days the pilot light is enough to keep the building plenty warm.
Here's my pump house taken last fall. The solar panel keeps the generator battery charged. The generator runs the well pump.

 

[Supervisor42]

It will always be more efficient to just heat/insulate the batteries than to try to heat a bigger space/mass like a shed.

Why wouldn't an old electric-blanket on top of them work?

 

[Hardcalibres]

Why wouldn't an old electric-blanket on top of them work?

How many watts did they draw?

 

[Supervisor42]

How many watts did they draw?

I think I remember a max of 300 watts.

 

[Cabin Fever]

I have three LiFePO4 batteries in my RV. They are 12 volts, 125 amps each and they have internal heaters. During out cold weather they had an alert that they were doing a low temp charge. WTH! Why? They had internal heaters. I guess out below zero temps were too low for the battery heaters to heat above freezing. So, I unplugged the batterie's from shore power. Charging LiFePO4 batteries below freezing temps will eventually destroy the battery.

 

[Biggkidd]

Which is why I went this route. It was the lowest draw self regulated real heat that wouldn't overheat the batteries I could think of. This should be enough tape for lack of a better word to go around my 32 cells twice or nearly twice. The current plan is to "cage" the batteries in 2x4's right in the middle to keep the cells from expanding and then put tape top and bottom. Then wrap on R13 keeping the heat in. Hopefully this way the heat tape will run little as possible. Only coming on when the temp drops to under 38f between the battery cells and the insulation where the built in thermostat will be.

 

[Magus]

You could upscale this one to heat a room in an emergency.

 

[Magpie]

I used T1-11 also on my pump house. I put rolled insulation between the studs and then put 2" insulating boards for the ceiling and on the walls. Except on the coldest days the pilot light is enough to keep the building plenty warm.
Here's my pump house taken last fall. The solar panel keeps the generator battery charged. The generator runs the well pump.
View attachment 171378

That's the best looking pumphouse I've seen!
My neighbour has one in a field across from me, (not as nice) with a red light bulb in it. The morning after our last big storm, the door blew off it, so it left a red glow in the dark, looking like a fire. Taking my son to work early he sighed and said 'I see the portal to hell is open'

 

[Aerindel]

I would use a glue on heat pad, like the type used to heat car oil pans. I used to install them all the time in alaska.

 

[zoomzoom]

They make battery heaters. Might be able to use them for however long it takes to warm them to above freezing.

An example

 

[UrbanHunter]

I have some LiFePO4(Li) batteries in the house, and a lead-acid battery bank in the unheated walkout area. The lead acid batteries are not safe for indoors but the FiFePO4s are. I think if I were going to go all Li batteries, I would want to place them either in a root cellar or a safe room in the basement, in either case the thermal mass should be enough to keep them operational.

 

[Aerindel]

The lead acid batteries are not safe for indoors but the FiFePO4s are.

So they say.......I just replaced my indoor lead acids with lithium irons...I admit, the lithiums make me more nervous. I'm trying to figure out a better place to put them.

 

[Hardcalibres]

So they say.......I just replaced my indoor lead acids with lithium irons...I admit, the lithiums make me more nervous. I'm trying to figure out a better place to put them.

Lithium battery fires seem to be common with Lithium Ion.

I haven't heard of a fire that started in a LiFePO4.

A lot of LiFePO4 batteries have been installed in Camper Trailers and boats......which are both very indoors applications.

Vehicle installs have the additional risk of vibration/physical damage to the batteries......and even then, there don't seem to be issues.

 

[Mountain trapper]

I use lead acid batteries in my battery bank. I have 12 Rolls, 2 volt 1169 amp hours each and love them. Everyone talks about the maintenance on lead acid batteries as a negative, but in 18 months I've only added water 3 times. I still check the water level monthly though. So far I've never heard any reason to buy any other battery regardless of cost.

 

[Hardcalibres]

I use lead acid batteries in my battery bank. I have 12 Rolls, 2 volt 1169 amp hours each and love them. Everyone talks about the maintenance on lead acid batteries as a negative, but in 18 months I've only added water 3 times. I still check the water level monthly though. So far I've never heard any reason to buy any other battery regardless of cost.

Our camper trailer came new fitted with two 100Ah SLA AGM batteries.

We used them for a while and then replaced them with two 250Ah LiFePO4 batteries........which are lighter........ and run the camper for about 6 times as long........and the batteries recharge a lot faster........and the voltage curve is almost flat........and they don't off gas Hydrogen.......and they will run a 3000W inverter.......and they have about 3-5 times the cycle life.

Our experience was an apples for apples comparison........running the same power draws.

 

[Mountain trapper]

Our camper trailer came new fitted with two 100Ah SLA AGM batteries.

We used them for a while and then replaced them with two 250Ah LiFePO4 batteries........which are lighter........ and run the camper for about 6 times as long........and the batteries recharge a lot faster........and the voltage curve is almost flat........and they don't off gas Hydrogen.......and they will run a 3000W inverter.......and they have about 3-5 times the cycle life.

Our experience was an apples for apples comparison........running the same power draws.

I'm far from a battery expert. In the 10 years since I installed solar up here I'm on my second set of batteries, both lead acid. The first set were Trojan 6 volt batteries × 8. They worked ok until they didn't. Towards the end of their life I was adding water about weekly. The last straw was when one of the batteries blew the top off while I was bending over looking at it. I've had these new Rolls batteries × 12 for about 18 months now. Unless something happens to change my mind I'll buy another set of Rolls batteries in about 10 or 15 years.