LiFePO4 heating pad for cold temperatures

[Will Prowse]

If you are trying to use a lifepo4 battery in freezing cold temperatures, battle born just released a 12v heat pad for keeping the batteries warm without melting the case. This pad should work for any standard lifepo4 battery. Just slap it under your batteries and connect it to 12v and you are done.

I think it is over priced though. It can be found here: Click Here for battle born heater pad


If you cannot afford the battle born pad, you can use a septic tank heater pad. It works in the same way but may possibly melt your battery case if you are not careful. You can avoid this by adding some protection or a way to distribute the heat across your entire battery bank. I would personally put the batteries in a insulated container, then add a thin sheet of conductive material like sheet aluminum over the pad so that the heat it produces can warm up your entire battery bank.

Cheaper heater pad source: Click here for heater pad

 

[Bulwinkle]

This is good info... there is a whole community of us who are Overland Camping folks. Overland Bound and Expedition Portal are 2 great sites... The issue of battery freezing vs efficiency is on my mind. I live in Maine and will only use the Overland Trailer once and awhile, but it also could get cold while using... What do you recommend for something that can get cold and not used full time??.

 

[somewhereinusa]

Battle born certainly are proud of their products. I've been studying the various heating pads available. I think the ones like your second link have the thermostat set wrong. I would think that 36-38° on and 40-45° off would suit our needs, you don't need to do anything other than keep it above 32°. I haven't found any that are available without a thermostat. There are all kinds of digital temp controllers available. I think you could wire one of them to control the ones with built in thermostats but, seems too jury rigged to me.

 

[mis353]

Will,
I just found these lithium ion iron phosphate batteries online. I know "nothing"about them, but was hoping you could do some testing on them and see what you come up with

65Ah 12V (12.8V) Lithium Iron Phosphate (LiFePO4) Smart Battery

Miller Tech lithium batteries are lightweight, non-toxic, and long lasting compared to traditional lead acid batteries. Each battery has a built in battery management system (BMS) which provides safety and proper charging/discharging. Each battery also features a built in state of charge (SoC)...

ldsreliance.myshopify.com

Thoughts?

 

[Alfabiker]

This is good info... there is a whole community of us who are Overland Camping folks. Overland Bound and Expedition Portal are 2 great sites... The issue of battery freezing vs efficiency is on my mind. I live in Maine and will only use the Overland Trailer once and awhile, but it also could get cold while using... What do you recommend for something that can get cold and not used full time??.

Here in the UK there are some specialist electrical engineering suppliers such as RS-online who have some interesting products that might be suitable and presumably are also available elsewhere e.g https://uk.rs-online.com/web/c/auto...ter-mats/?sra=p&applied-dimensions=4294572632

 

[somewhereinusa]

I contacted an ebay seller that said they do custom size mats. The will do a 10x25 12V 150W mat without thermostat for $125. Seems like a decent price to get exactly what I want. I am also going to use another temp controller to disconnect the batteries from everything in the event that they get near 32°

The odd thing is, they say that they use mat material that is manufactured in the US. Has anyone researched just how these mats are constructed?

 

[PHoganDive]

Watlow makes a pretty good selection of them, various sizes, voltages and wattages.

| Watlow

www.watlow.com

 

[somewhereinusa]

That 7.5 x 25 looks about right for my installation

 

[mtt04]

If you are trying to use a lifepo4 battery in freezing cold temperatures, battle born just released a 12v heat pad for keeping the batteries warm without melting the case. This pad should work for any standard lifepo4 battery. Just slap it under your batteries and connect it to 12v and you are done.

I think it is over priced though. It can be found here: Click Here for battle born heater pad


If you cannot afford the battle born pad, you can use a septic tank heater pad. It works in the same way but may possibly melt your battery case if you are not careful. You can avoid this by adding some protection or a way to distribute the heat across your entire battery bank. I would personally put the batteries in a insulated container, then add a thin sheet of conductive material like sheet aluminum over the pad so that the heat it produces can warm up your entire battery bank.

Cheaper heater pad source: Click here for heater pad

Hi Will.

I posted about lead crystal silicon dioxide batteries and if anyone has tried them

They are selling here in Canada as severe weather battery solutions.

The tech is new and is not well known. It would be interesting if they would send you one to try out.
And always,

Thank you for your service
Cheers mate.

 

[somewhereinusa]

I've had some cold temps for a couple of mornings to test my heat pad with external digital thermostat. The pad is like the one Will posted at the bottom of his original post. I used settings a bit lower than the ones the pad comes with. Both mornings of about freezing my batteries were at 50.3° F
I have some ideas about making my own that won't be limited to any predetermined shape or size. Waiting on some parts to show up from China. More to come.

 

[brassmonkey001]

My Fridge (A Vitrifrigo C75L) has a remote heat exchanger. I was toying with the idea of building a well insulated battery box inside the living area with perhaps locating the heat exchanger inside the box thus using the heat to help keep the chill off the batteries? I don't know how effective this would be but I thought it could a handy way of making use of energy that would otherwise be wasted.

 

[somewhereinusa]

My Fridge (A Vitrifrigo C75L) has a remote heat exchanger. I was toying with the idea of building a well insulated battery box inside the living area with perhaps locating the heat exchanger inside the box thus using the heat to help keep the chill off the batteries? I don't know how effective this would be but I thought it could a handy way of making use of energy that would otherwise be wasted.

Interesting idea, I hadn't seen that kind of set up before. Basically a tiny mini-split? The first problem I see would be in the summer time, adding more heat to the battery box. If your batteries are in the living space they should get no where near freezing. The only problem with liths is charging when below freezing. I don't take the bus out much, if ever, in the winter. I'm just using the heat pads to make darn sure the batteries never get charged when they are below freezing. Besides the heat pad, which is set to come on about 38°F I also have a total disconnect of the batteries from everything set at about 35°F.
While I don't really take the bus anywhere in the winter I am still working on it and need power all winter. One thing about the fancy inverter/chargers with AC pass through is that they wont turn on unless they "see" DC voltage. I think, I'm going to run the liths down about half way and disconnect them, then hook up a lead acid. It's easy enough to change the charger for lead acid and then back. It's just a saved setting change.

 

[brassmonkey001]

Interesting idea, I hadn't seen that kind of set up before. Basically a tiny mini-split? The first problem I see would be in the summer time, adding more heat to the battery box. If your batteries are in the living space they should get no where near freezing. The only problem with liths is charging when below freezing. I don't take the bus out much, if ever, in the winter. I'm just using the heat pads to make darn sure the batteries never get charged when they are below freezing. Besides the heat pad, which is set to come on about 38°F I also have a total disconnect of the batteries from everything set at about 35°F.
While I don't really take the bus anywhere in the winter I am still working on it and need power all winter. One thing about the fancy inverter/chargers with AC pass through is that they wont turn on unless they "see" DC voltage. I think, I'm going to run the liths down about half way and disconnect them, then hook up a lead acid. It's easy enough to change the charger for lead acid and then back. It's just a saved setting change.

Hmm, I hadn't considered the other end of the scale, I was only thinking about the coming winter and trying to use what is to hand rather than buying something else.
I would say that the living space could easily get below freezing if you weren't in there for a couple of days, especially at night during a cold spell.
That heat pad Deno linked to looks like a good solution though, and cheap too!

 

[Supervstech]

There should be a dump mode so when the bms senses temps below 34F, charge power switches to heating elements to maintain pack temp for charging.

 

[offgriddle]

Ty for the tip. I put my Lifepo's in an insulated box in my root cellar. Even if it's 30 degrees below 0 outside, a deep enough hole that HAS NO WIND MOVEMENT will remain above freezing.

 

[offgriddle]

This is good info... there is a whole community of us who are Overland Camping folks. Overland Bound and Expedition Portal are 2 great sites... The issue of battery freezing vs efficiency is on my mind. I live in Maine and will only use the Overland Trailer once and awhile, but it also could get cold while using... What do you recommend for something that can get cold and not used full time??.

Presently, lithium batteries, which out perform flooded lead acid and AGM lead acid in so many ways, cannot be charged below 32 degrees and apparently should not even be stored below zero degrees. I guess if you need low temp tolerant batteries, go with AGM. Ayuh.

 

[somewhereinusa]

Presently, lithium batteries, which out perform flooded lead acid and AGM lead acid in so many ways, cannot be charged below 32 degrees and apparently should not even be stored below zero degrees. I guess if you need low temp tolerant batteries, go with AGM. Ayuh.

The manual for Valence batteries states storage temps of -40°C and 50°C, Ideally < 30°C for maximum life.

 

[brassmonkey001]

8°c tonight and will probably be cooler by morning so I've disconnected the solar panels just in case. I'd best get one of those mats ordered I guess.

 

[brassmonkey001]

Just spotted this nice and cheap and might be workable if you add a thermostatic switch to control it?

 

[eddie1261]

When it gets that cold here I will just take the battery out and bring it inside. But I am many weeks from "that" cold here.

What exactly IS the temperature where we need to worry about it? In farenheit please. LOL!

I see some 12v heating pads on Amazon. Which begs the question, isn't a heating pad just a wire run up and down the insides of a rubber pad? Seems like one of the more brainiac types here could actually build one. We have some good minds here!!

12x18 12v heating pad