Late last year we moved from southern CA to Yakima WA. Oh dear it’s cold here - below freezing 24/7 for the past ten days. Last Friday it was -2 overnight. I didn’t really consider freeze-protection in an active way when I built my battery, but at least it got moved indoors to under the sofa-bed. Removing the battery pack for the winter months would be a giant hassle - it is more or less built in.
I do have Overkill BMS with its two sensors, ambient and battery, and it will shut down charging under 33 degrees, so at least there’s that. But really, I didn’t want it freezing at all, seems like a bad idea all around. And heating the entire RV didn’t seem like a good option either - I just needed to keep the battery from freezing.
So I bought one of these bilge heaters - Twin Hornet 45 - it’s high volume low temperature, comes on at about 35 and shuts off about 50. It’s 700 watts, and I leave the coach plugged in while parked in the driveway so it stays powered up. Since my battery pack is inside under the sofa this heater warms that whole area and the lowest I’ve seen the on-bat temp sensor is about 35, but generally it stays just under 40. Ambient ranges from 40-50. This is the best $300 I’ve spent on this coach.
Probly not the best option for a traveler, but for a parked rig is nothing short of fantastic. And I can keep my battery fully charged up, don’t have to disconnect or reprogram anything.
I also got a ‘battery blanket’ for the starting batteries, and put it on a timer that turns it on during cold periods. Got one for the toad too - it has to live outdoors with a cover on it. The other cars are in the garage and it never drops below 45. Damn it’s cold here!
I do have Overkill BMS with its two sensors, ambient and battery, and it will shut down charging under 33 degrees, so at least there’s that. But really, I didn’t want it freezing at all, seems like a bad idea all around. And heating the entire RV didn’t seem like a good option either - I just needed to keep the battery from freezing.
So I bought one of these bilge heaters - Twin Hornet 45 - it’s high volume low temperature, comes on at about 35 and shuts off about 50. It’s 700 watts, and I leave the coach plugged in while parked in the driveway so it stays powered up. Since my battery pack is inside under the sofa this heater warms that whole area and the lowest I’ve seen the on-bat temp sensor is about 35, but generally it stays just under 40. Ambient ranges from 40-50. This is the best $300 I’ve spent on this coach.
Probly not the best option for a traveler, but for a parked rig is nothing short of fantastic. And I can keep my battery fully charged up, don’t have to disconnect or reprogram anything.
I also got a ‘battery blanket’ for the starting batteries, and put it on a timer that turns it on during cold periods. Got one for the toad too - it has to live outdoors with a cover on it. The other cars are in the garage and it never drops below 45. Damn it’s cold here!
Last edited:
