Battery Wiring Warmer, Is this Smart?

Oldtoad

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Wired the battery warmer in before the BMS, so the solar panel can warm the LiFePos cells if the heating pad temperature controller calls for it.
Of course if the BMS temp sensor is above the the cutoff temp the cells can warm the package.
Should I put a fuse between the Epever charge controler and the warming blanket, just has the temperature switch with16ga wire?
1649152975186.jpeg
 

mikefitz

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Don't quite understand where the power for the heater is taken from in the system , perhaps a diagram?

Comments.

Having the BMS buried under insulation may not be a good idea.

For a mobile application the cells do not seem to be restrained adequately.

Mike
 

Zil

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The battery heater, "blanket", and the thermostatic control, has a positive voltage supply. That needs a fuse to protect that wire. The fuse needs be at the positive-battery-source end of the wire. My 16 gauge wire can carry 25 amperes, I would fuse it at 25 amperes.
I agree, that pink shtuff provides no resistance against swelling. or restraint against movement..
 

HRTKD

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I'm trying to follow your wiring and it looks to me like your battery warmer is downstream of the BMS.

Battery -> BMS -> Warmer, Thermostat, Switch -> ...

I don't have a problem with that sequence. Be sure to set your thermostat to have a lower threshold that is higher that the low temperature cutoff setting of the BMS. Note that the low temperature cutoff is for charging. The BMS should still discharge well below that low temperature cutoff.
 

mikefitz

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Many cell manufactures allow charging at a reduced rate down to -10C.
With a small RV application with the battery inside the vehicle with the occupants is a heater required?

Mike
 

timselectric

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Many cell manufactures allow charging at a reduced rate down to -10C.
With a small RV application with the battery inside the vehicle with the occupants is a heater required?

Mike
Not needed.
As long as the temperature stays above the low temperature cut off.
 

Oldtoad

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Don't quite understand where the power for the heater is taken from in the system , perhaps a diagram?

Comments.

Having the BMS buried under insulation may not be a good idea.

For a mobile application the cells do not seem to be restrained adequately.

Mike
The power for the heating pad is the negative terminal and the unswitched side of the shutoff.
Multiple industrial wide zip ties compress the cells.
A picture tells a thousand words, a diagram that I cannot draw might not tell the truth.

Thanks Zil, just what it needs.

Thanks HRTKD, I will check those temp settings. But I think that is the way it is.
 
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