24v heating pads on 4s battery packs?

[ericfx1984]

A While back I bought a whole bunch of 24 volt battery packs off the battery hookup for super cheap

I have a pretty large 4S battery bank and it's pretty cold right now

I did go ahead and test by hooking up to a car battery... And the results are that the heating pad draws about 3.6 to 3.8 amps. He gets really hot... So much so that you don't want to keep your fingers touching it for two terribly long... It looks like overall that's about 50 watts...

Is there any potential issue that you can think of with running a 24 volt heating element on a 12 volt power source?

 

[Partimewages]

If it's just resistance heat then you get 25 watts. That might still be to much. Two in series would cut it down more.

 

[ericfx1984]

If it's just resistance heat then you get 25 watts. That might still be to much. Two in series would cut it down more.

That's a good thought... I'm not sure why I hadn't thought about that... I'll experiment with that tomorrow...

 

[ericfx1984]

If it's just resistance heat then you get 25 watts. That might still be to much. Two in series would cut it down more.

Okay it looks like we get about 2.65 amps with a pair of them in series... They don't put out nearly as much heat but that's about 35 or so watts

 

[740GLE]

Also the heating element in bare air will warm up much faster than if it were directly contacting cold cells.

Is there a thermostat built into the element or are you relying on the BMS or other external control mechanism.

 

[ericfx1984]

The seller suggests a pair of them in series of you run them at 48v

So why would I run them in series at 12v if they are designed for 24v?

Is it a current issue or a heat issue?

 

[ericfx1984]

Also the heating element in bare air will warm up much faster than if it were directly contacting cold cells.

Is there a thermostat built into the element or are you relying on the BMS or other external control mechanism.

I don't this the tstat is built it... They never seem to shut down

 

[740GLE]

Maybe that’s why battery hook up was selling them ?

 

[ericfx1984]

Maybe that’s why battery hook up was selling them ?

Actually just talked to the manufacturer... They say that it does have a high temperature shut off switch built in

He also made sure to mention that it's pretty important to have this properly adhered to the battery otherwise the heat transfer will not be enough and it could potentially burn the unit out... Though he says typically they don't build these with high temperature shut off switches, that's somewhat of a unique addition... And he says that should help to keep it protected

 

[fpgt72]

Actually just talked to the manufacturer... They say that it does have a high temperature shut off switch built in

He also made sure to mention that it's pretty important to have this properly adhered to the battery otherwise the heat transfer will not be enough and it could potentially burn the unit out... Though he says typically they don't build these with high temperature shut off switches, that's somewhat of a unique addition... And he says that should help to keep it protected

??

I really worry about my batteries in this last cold snap, -14F. I went out and checked on them from time to time, and while not "warm" they are not freezing, so I think that is good.

Well insulated to keep the heat in I think goes a real long way.

Personally I would want to make sure they have a high temp cutoff.

 

[time2roll]

Heat should be mild running at half voltage. Two in series is even less.
I run my small 12v heat pads as two in series for less heat. Works perfect. I use a temperature controlled relay to keep the battery 40 to 44 degrees.

Get them connected and monitor temperature every 20 minutes until the effect is known.

 

[yoopNreb]

Actually just talked to the manufacturer... They say that it does have a high temperature shut off switch built in

He also made sure to mention that it's pretty important to have this properly adhered to the battery otherwise the heat transfer will not be enough and it could potentially burn the unit out... Though he says typically they don't build these with high temperature shut off switches, that's somewhat of a unique addition... And he says that should help to keep it protected

https://batteryhookup.com/products/24-48v-150w-battery-heating-pad-hi-heat-made-in-usa

Are these the heating pads? What temperature did the manufacturer say high temp shutoff is activated? Did they suggest how to adhere them to the batteries? Any other info they provided? I’m new here, and also toying with these.

 

[fpgt72]

https://batteryhookup.com/products/24-48v-150w-battery-heating-pad-hi-heat-made-in-usa

Are these the heating pads? What temperature did the manufacturer say high temp shutoff is activated? Did they suggest how to adhere them to the batteries? Any other info they provided? I’m new here, and also toying with these.

I will have to look at home to see what mine are, but those are not it.

IIRC mine shutoff at 40-something. I know just yesterday I put my hand on the pads and they are cool to the touch. It was mid 70's yesterday. This morning it is 20F so I bet they kicked on again.

Stupid weather.