LiFePo4 Battery Warmers

[Sloughpump]

I've been searching for a battery warmer that is "corded rather than 12 volt, running off the battery itself. I've found warmers for reptile/fish aquariums, auto battery warmers (short-use time), engine blankets, and a couple 12 volt warmers that run directly off the battery being warmed. Also, are they thermostat controlled? Can anyone share any products or recommendations. Unfortunately, living in the Northland means cold late spring temperatures, 24 and 26, the last two nights. Thanks.

[travelin texans]

Originally Posted by Sloughpump

I've been searching for a battery warmer that is "corded rather than 12 volt, running off the battery itself. I've found warmers for reptile/fish aquariums, auto battery warmers (short-use time), engine blankets, and a couple 12 volt warmers that run directly off the battery being warmed. Also, are they thermostat controlled? Can anyone share any products or recommendations. Unfortunately, living in the Northland means cold late spring temperatures, 24 and 26, the last two nights. Thanks.

Curious?
You've spent the big money on Lithium batteries but want to plug in the warmers to 120, why purchase those batteries?

[pasayten]

I bought two Battleborn 12v 100ah heated LiFePo4 batteries... They have an internal heater that is much more efficient than a wrap style heater. It is controlled by an internal thermostat and draws about 25 watts per battery only when needed.

From their FAQ's...

"The resting draw of the heater enable in the BB10012H is 0A. It will only draw power when the heat enable is engaged and the internal temperature of the battery reaches 35F."

"On average, the heated battery consumes an average of 1.8 amps. Our tests indicate that at 0 degrees Fahrenheit, with no insulation, the heater is on about 30% of the time. With no external charging or loads it gives approximately 185 hours of heat capability before the battery goes into low voltage disconnect. With warmer temperatures you can consume less power and if you insulate your batteries you can extend the usage as well. "

[BigBobIa]

Originally Posted by pasayten

With warmer temperatures you can consume less power and if you insulate your batteries you can extend the usage as well. "

So you insulate the battery box for under temp purposes. Does that impact hot weather over temp cutoff?

[pasayten]

I didn't insulate mine, but in thinking about it, maybe a little foam "cozy" in the air space between the battery and its case would help? It could also be pulled out during the summer. I figure on trying out cold weather situations first before I take any additional steps... We are "north landers" also... Live in eastern WA state about 40 miles from the Canadian border... :-)

[xrated]

I'm in the process of building a 302AH LFP battery and it will be going into a box that I built. It is insulated and heated and will be powered off of the batteries themselves. There are four 7 1/2W 12V heaters and the control will be a 12V digital temperature controller that has it's own sensor probe to turn the heater off/on. 30W total power draw which is right at 2.2 amps when the heater are on. Based on what I've seen from others posting, even when the temperature get into the teens and 20s overnight, I guessing the heaters will only be on two or three times in a 12 hour period for maybe 45 minutes to an hour. Worst case...three times for an hour is only about 6 1/2 to 7 amp hours our of a 302 AH battery....Here's a couple of pics. of the work in progress....

[Sloughpump]

During warmer weather, I do camping solely with battery/propane power. Shoulder seasons and other times, I'm on a 50 amp pole.Thinking on those cold mornings, the converter could charge the battery, although I believe the BMS would prevent that...but then charging would cease as well....

[Sloughpump]

This looks great/promising. I see the Facon strips (x4). I've seen a single strip used for one battery drawing power from the battery itself. But, no thermostat. it's manual on and off, and says a .5 amp draw. May be ok. I thought when on a 50amp post, why not plugnin, with a thermostat if available....

See: Off Grid Power Pack online:
"Lithium battery heating system allows you to use your lithium batteries on those cold weather campouts. We can fit any size lithium battery. Uses only 1/2 amp draw! Complete package costs $149.95."

Pricey though!!!!!

[pasayten]

Originally Posted by Sloughpump

Thinking on those cold mornings, the converter could charge the battery, although I believe the BMS would prevent that...but then charging would cease as well....

That's what I like about my Battleborn batteries with the built in heating option... The BMS/battery will warm themseleves for charging... :-)

[xrated]

Originally Posted by Sloughpump

This looks great/promising. I see the Facon strips (x4). I've seen a single strip used for one battery drawing power from the battery itself. But, no thermostat. it's manual on and off, and says a .5 amp draw. May be ok. I thought when on a 50amp post, why not plugnin, with a thermostat if available....

See: Off Grid Power Pack online:
"Lithium battery heating system allows you to use your lithium batteries on those cold weather campouts. We can fit any size lithium battery. Uses only 1/2 amp draw! Complete package costs $149.95."

Pricey though!!!!!

Yes, Facon 7 1/2 watts per strip....that 30W total and current draw is right at 2.2 amps. The digital controller (not pictured, it's already mounted in the trailer generator/battery/hydraulic bay) is also operated on 12VDC and everything receives power from the battery. The controller is very adjustable and can be set to about any temperature settings that you want and also has a 20° temperature offset. That means for example, I can set it to come on at let's say 38° and turn off at 58°....or 48° or whatever temperature within that 20° spread.

I looked at a few of the larger "tank heaters" and they are just too much power/heat for a small box like this that is totally enclosed and insulated. 30Watts of power is equal to just over 100 BTUs of heat and that should be more than sufficient for a box this size. The idea of a heated box is to heat the inside "low and slow"....not huge and quick. Once the battery(s) get cold, it will take a while for them to soak in the heat, and this is always preferable over high heat and possibly damaging the battery.