Tell me about those heat pads some batteries have internally

[Flunkyboi]

I'm in a fairly mild climate area (Alabama), but it can get cold here. A few weeks back, we had some 16°f nights.
My new LFP batteries are not heated. I've read a couple of battery heater threads here and have seen DIY battery assembly videos where people install their own in homemade batteries.
I will build an insulated battery enclosure before next Winter. 2" closed cell insulation board. I know most batteries with heaters built in drive them with the BMS temp sensing and use the battery's own stored power.

I am thinking about controlling the pad with a refrigerator icing Klixon switch. These go closed circuit at 32° and go open circuit just above that temp. These are series wired in refrigerator defrost circuits. They control defrost circuit mullion elements, inside a refrigerator's evaporator coils. This melts the ice during the timed defrosting cycle.

I've seen these little switches that still worked after decades of cycling high amperage/voltage every day.

I know nothing of those little heater pads . My batteries are a bank of 12v seriesed to 48v. I either need one pad, say built for a 48v golf cart battery or four smaller 12v batteries. (Series those to run on 48v.)

What are they called?
Vendors?
What wattage would be typical with one found inside of a premium 12v battery? Thanks.

 

[Backyard]

My experience with those Klixon switches for ice makers is they cycle closer to 17° or so. +- a degree or two

They are long lived for sure but I've still replaced a dozen or so of them over the years doing appliance repairs. A lot cheaper then a whole ice maker

Amazon and others will have thousands of those snap switches at whatever temperature you want for a few dollars.

 

[Flunkyboi]

I assumed they hit 32° and closed. Ideal temp range would be "close at 34°, open at 40°"

Aside from buying a 48v BMS, solely to utilize it's heat monitoring circuitry, I wonder what other options there are to use to drive the heat pads?

My solar shed is an uninsured out building. The current battery bank of four 12v was bought as a temporary 48v arrangement. Those batteries will eventually be used on other projects. One of those will still require low temp protection.

 

[robby]

The built in heat pads Turn on in the morning when there is enough sunlight to power them and only if the temperature is at or below freezing.
Once the battery is warm enough the energy is diverted back to charging the battery.

 

[Backyard]

I assumed they hit 32° and closed. Ideal temp range would be "close at 34°, open at 40°"

Aside from buying a 48v BMS, solely to utilize it's heat monitoring circuitry, I wonder what other options there are to use to drive the heat pads?

My solar shed is an uninsured out building. The current battery bank of four 12v was bought as a temporary 48v arrangement. Those batteries will eventually be used on other projects. One of those will still require low temp protection.

The temp is set for something like 17° to insure the water is frozen. At 32° water is a mix of ice and water. It's going through the ice phase which has a high laten heat. Thus water won't drop below 32° until all of it has turned to ice. Thus the reason for setting the temperature of the snap switch lower.

Then it turns on the heating element to release the ice from the tray/mold

 

[outboard1196]

I'm in a fairly mild climate area (Alabama), but it can get cold here. A few weeks back, we had some 16°f nights.
My new LFP batteries are not heated. I've read a couple of battery heater threads here and have seen DIY battery assembly videos where people install their own in homemade batteries.
I will build an insulated battery enclosure before next Winter. 2" closed cell insulation board. I know most batteries with heaters built in drive them with the BMS temp sensing and use the battery's own stored power.

I am thinking about controlling the pad with a refrigerator icing Klixon switch. These go closed circuit at 32° and go open circuit just above that temp. These are series wired in refrigerator defrost circuits. They control defrost circuit mullion elements, inside a refrigerator's evaporator coils. This melts the ice during the timed defrosting cycle.

I've seen these little switches that still worked after decades of cycling high amperage/voltage every day.

I know nothing of those little heater pads . My batteries are a bank of 12v seriesed to 48v. I either need one pad, say built for a 48v golf cart battery or four smaller 12v batteries. (Series those to run on 48v.)

What are they called?
Vendors?
What wattage would be typical with one found inside of a premium 12v battery? Thanks.

There's a whole thread about battery heaters.

Thread 'LiFePO4 heating pad for cold temperatures'

Sep 20, 2019

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...

• Will Prowse
• Replies: 788
• Forum: Off-grid Living Discussion

• 

 

[Flunkyboi]

There's a whole thread about battery heaters.

Thread 'LiFePO4 heating pad for cold temperatures'

Sep 20, 2019

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...

• Will Prowse
• Replies: 788
• Forum: Off-grid Living Discussion

• 

Will do some study. Thank you.

 

[outboard1196]

Will do some study. Thank you.

Mines on the last page FYI. Probably too small for you.