Battery warmer for LiFePo4 Batteries.

[WalterM6]

When it's cold outside my underload battery voltage drops down to 44v. I'm think of making a Styrofoam enclosure with a heating pad inside to keep my batteries at about 80-90 degrees F. Has anybody ever tried anything like this? Hoping for some suggestions.

[CP241]

I’ll be honest, I’ve been contemplating the same thing.

[Volt_Ampere]

You only need to get them up in the 50 to 60 degree F range.

[Tom47]

These might work:

https://www.amazon.com/Zerostart-280.../dp/B002UNASS4
This is not recommended for ABS cased lithium.

https://www.truckcamperadventure.com...ng-system-mod/

https://www.amazon.com/dp/B01MUWG8QW/ref=emc_b_5_t

[DaveTM]

I've looked into this before.....not all that in-depth but for a hunting cart in the cold, warm batteries can make the available trip distance much better.

I was considering hooking up a 12V "fan" type heater from my separate Marine battery with something like this: https://www.amazon.com/Constant-Temp...25520223&psc=1

The advertised space this can heat is show to be .5 cubic meters, which if I do my math right translates to about 17.5 cubic feet.

Just thinking out loud.

[kgsc]

If you can figure out a way to enclose it a plain light bulb would work as a heat source. I used to use a 100w bulb in my well house and it would keep it over 70 deg in there and it was 20 outside. Was like 4ft by 4ft by 3ft

[WalterM6]

Thanks everybody for the helpful suggestions. The solution turned out to be something completely different. I was reading through the archives and came upon a post by DaveTM. In his post he remarked that he was having low voltage cutoff's. He found that he had typed in the low voltage cutoff incorrectly. I checked my settings and found that my Low Voltage cutoff should have been set at 40v instead of 44v. I also reduced my Max Battery Current to 250amps like he did and it's back running like new again. Maybe a little slower going up large hills but on the flats it runs great.

I'm still going to try and heat my battery compartment. Just to reduce the stress of the cold weather pulling my batteries down. I've attached a few pictures of my first design. I placed a heating pad under my protective battery shield and covered it with a folded drop cloth. Very high-tech redneck. 😁

[DaveTM]

Originally Posted by WalterM6

I was reading through the archives and came upon a post by DaveTM. In his post he remarked that he was having low voltage cutoff's. He found that he had typed in the low voltage cutoff incorrectly. I checked my settings and found that my Low Voltage cutoff should have been set at 40v instead of 44v. 😁

Hmmm.....I did a search of my post to attempt to find where I said my LV cutoff was set at 40V (for the pack).

Now, I may have set my CONTROLLER LV cutoff of 40V....and that would give a per cell voltage of (40\14)=2.85VPC.

But my CURRENT BMS LV setting is 3.14VPC which is a pack voltage of 43.96 or 44.

If I stated the LV cutoff on the BMS at 40V (pack voltage) then I'd have to see that post to determine if it was a mistake or I ment something else. If it was a mistake I think I can edit it to correct.

I'd suggest you change your BMS LV cutoff back to the 44V.

[WalterM6]

This is the post I was talking about. Re-reading it you were talking about HV Cutoff maybe it triggered my brain to check cutoff voltages. Turns out my situation was the opposite of yours. https://www.buggiesgonewild.com/showthread.php?t=181126 The LV Cutoff is at 40v because I have a LiFePo4 pack.

[Volt_Ampere]

My BMS Cutoff is based on the lowest cell voltage. All of them should be this way. Total voltage should not be used for LV cutoff.