When should you turn on battery heater?

DaveC

I just picked up my 2023 400 with 1 lithium battery.  Can't find any reference to the battery heater switch in the online manual (didn't get a printed manual!!).  If I am connected to shore power at night with close to freezing temps do I need to have the battery heater switch on?  Is the battery being charged from shore power?  If so, is the battery damaged by not having the heater on?

Dutch061

Since the batteries are under the bed, I seriously doubt you will ever need to turn the heater on while you are using the camper.

As per Battleborn, the BMS is set to disable charging below 25 F, as charging can cause serious irreversible damage to LifePO4 batteries. However, discharging at temperatures below 25 F will not cause any damage.

When we had our 400, I had 400 Ah of Battleborn under the bed, a Victron Smart Shunt with a temperature sensor, there was never any danger of the batteries being too cold while using the camper. 

So, the only time I could imagine ever using the heater would be if I lived in a very cold climate and was planning to use the camper. I would possibly need to use the heater(s) until the interior temperature (specifically under the bed) was above 25 F. Since the Alde is also under the bed, the temperature will rise pretty fast, and remember the BMS is going to protect the battery anyway. Chances of actually using a TAB below freezing is not very high unless you have done some modifications. They are not insulated that well, and are very slow to get very warm once the ambient is in the low 30's. 

During storage, Battleborn recommends a state of charge above 50% and disable any charging or draws. So, Perko off and the Solar Charge Controller (if equipped) off, and no cord to shore power.

In my opinion, NuCamp chose the heated version due to the 320 series and batteries not in a heated compartment Rather than stock (or buy) 2 different models, it was simpler to stick with a single SKU.

Brad

bergger

I agree with what @Dutch061 has said.  If your trailer is just in storage and not being used there should be no reason to turn the heater on.  The battery will protect itself.  As long as the battery is charged over 50% it can sit for months without needing to be charged.  However since you have the trailer on shore power the battery will be charged as long as the temps are warm enough and if the temps drop the battery will protect itself by not taking a charge.  If you are using the trailer and for some reason the battery compartment is going to get cold enough to disable battery charging then you'd want to turn on the battery heater. 

AnOldUR

My LiFePO4's aren't Battle Born, but do have temperature cutoffs. There are separate low temperature cutoffs for charging and discharging. The charging cutoff is for freezing temperatures, but the discharging cutoff is much lower (I believe it's 21℉).

If you didn't have the heater function on while traveling in really cold temperatures, there's the potential for your battery to turn off discharging causing you to lose your emergency breakaway brakes.

dsfdogs

@DaveC If you are plugged into your home/shore power AND your battery switch is turned on, you are charging your battery. 

Recently I've been trying to charge mine overnight and temps dipped below freezing, so I flipped the battery heater switch.

In your "goody" bag from nuCamp, you should have received a couple brochures from Battle Born including one for the heating function.

pthomas745

In any case, your batteries should have "low temp charging protection."  If the battery (not the air temperature, the actual battery) reaches that "low temp" point, the battery is equipped with a low temp sensor that is supposed to shut off charging.

(Every owner considering a lithium battery should learn if your inexpensive battery has low temp charging protection or not, and how it works.  There are many workarounds that provide this protection.)

We have discussed Will Prowse here before, and he describes the issue around low temps and the lithium batteries.  In the video below, he explains that the batteries themselves "make their own heat", so the odds of a battery getting below the cut off inside the trailer is very low.  Simple insulation of the battery would work, to a point.

The other issue with the "battery heaters".  In the video, Will points out that if the battery heater activates, in some cases....that also cuts off charging until a certain (higher) temp is reached.   I have no idea if this is a factor in the Battleborns.

https://www.youtube.com/watch?v=EaiwxDUY9ho&t=39s

maxwellllll

Dutch061 said:

Since the batteries are under the bed, I seriously doubt you will ever need to turn the heater on while you are using the camper.

[ . . .]

In my opinion, NuCamp chose the heated version due to the 320 series and batteries not in a heated compartment Rather than stock (or buy) 2 different models, it was simpler to stick with a single SKU.

Brad

I can't imagine ever needing to heat the batteries.  Like...ever . . . but I live in South Texas, and while it does get very cold here from time to time, it rarely lasts more than a few days.  We occasionally camp in the very cold, but when we're camping, we've got the camper heater on. 

I think this is a good theory regarding "one SKU" for NuCamp.  So here's a question . . . 

If I'm looking to upgrade my 2023, is there any reason why I, personally, should be inclined to spend an additional $225 ($75 x 3 batteries) to get heated BattleBorns vs. unheated? 

pthomas745

The only reason to "heat" a battery is if you need to charge the battery while the BATTERY is below freezing...not the ambient air temp.  Some lithium batteries are equipped with a "low temperature charging protection" device that is attached to the battery.  If that sensor gets to a particular temp (it may not be below 32 degrees F) then charging is completely stopped.

I live in Southern California, and I realized that I did not need a battery with "low temp charging protection" and bought one of the inexpensive AmperTime batteries. 

And, watch the video above.  If the batteries are inside the camper, (you don't say what model you have) then the batteries should never reach 32 degrees.

AndreO

@DaveC,
Any time you feel there is a chance the temps could go below zero while charging then go ahead and enable the battery heater. Don't worry, in the case of Battle Borns, when the manual switch is activated the BMS will not actually activate the internal heaters unless it's sensors determin it needs to.

So basically the purpose of the manual switch is an override to ensure the BMS won't turn them on and therefore draw any power when you're in storage etc. and not planning to charge.

rcarlson1957

Depends on what lithium battery you have and where it is installed. We have a 100ah LiTime battery we installed a few years ago. As some have mentioned, low temp cutoff can be an important feature when camping and temps dip below freezing since you normally can't charge a lithium battery when it's temp gets below freezing. Our battery doesn't have that in it's BMS. I installed a 12v battery heater wrap as a work around. We camp during shoulder seasons up North to get away from the heat in Texas and sometimes the temps can drop below freezing during the night.  If the temp is going to drop we just turn on the battery heater so it can still charged. We normally camp with shore power but have portable solar panels if we don't have shore power. 

SLJ

We 3 season camp and mine have low temp cut-off built in. I installed mine inside under the passenger bench which has a heating element next to it so I doubt the low temp protection will ever kick on when we're using it. Also have the Victron battery monitor on the side of one of the batteries which cuts off the solar and my Victron smart charger if they're on. I have it set to cut off at 35 degrees. In the winter it's stored in my garage and I just shut the batteries off. They keep their charge all winter.