How to know if the battery heater is working on a 2023 T@b 400?

GrandFX
GrandFX Member Posts: 2
in Battery/Electrical & Solar

I recently purchased a 2023 T@b 400. Next to the bed there is a switch to turn on the battery heater. The LED turns on when I flip the switch, but how do I confirm it is actually working? I was told you cannot use the Victron App to see heater amp usage as the usage is internal to the battery and outside of the visibility of Victron. I tried to look at a drop in battery voltage on really cold nights where the outside temp has dropped to low 20's, but I don't see any material drop during the course of the night. Are there any ways to confirm the heater is working without putting some thermometer on the battery itself and trying to monitor?

Comments

  • pthomas745
    pthomas745 Administrator, Moderator Posts: 4,700
    edited November 1

    Welcome to the Forums!

    The battery heater will only engage when the temperature "inside the battery"…..not the ambient temperature, drops below 35F. The battery heater is really only "needed" if your battery (inside the battery) is below freezing, and you need to charge the battery. Most all lithium batteries have a "low temperature charging protection" circuit, which would prevent charging if the battery was below 32F. (All these temperatures are approximate).

    This will be really hard to test if you are using the trailer. Somehow, the temp inside the battery, which is under the bed in a 400, with a lot of insulation, would need to drop below 35F. That is why you are not seeing any voltage drop when the heater is "on". The heater is not kicking in. (Unless you enjoy a very cold trailer!)

    The issue with monitoring the battery status is with the Victron Shunt devices, not necessarily the Victron Solar Controller. For a shunt to accurately monitor the drop in amp hours, the switch would have to be wired through the shunt. ( I don't know how to describe how that might work!) So, if you have a shunt, and the heaters kicked on, the display of amp hours on the shunt would be incorrect. Since the heaters use about 1.8 amps, there could be a considerable mismatch in the actual amp hours used compared to what the shunt thinks it is.

    Your Victron solar controller, however, would show you the power being used by the battery heater.

    This is the section of the Battleborn "heater installation manual" that describes the issue with the "monitoring devices". The "BMV" mentioned here is a shunt device.

    image.png

    This is the note that describes the "internal temperatures" that would start and stop the heater.

    image.png

    This info comes from this Battleborn Guide

    Battleborn Heated Battery Installation Guide

    2017 Outback
    Towed by 2014 Touareg TDi
  • GrandFX
    GrandFX Member Posts: 2

    Thanks for the very detailed response.

    For clarity around my concern and your comment:

    Somehow, the temp inside the battery, which is under the bed in a 400, with a lot of insulation, would need to drop below 35F. That is why you are not seeing any voltage drop when the heater is "on". The heater is not kicking in. (Unless you enjoy a very cold trailer!)

    I am not concerned about temps when I am using my camper. I am concerned about the time it sits on the side of my house when not being used or heated internally. So I am assuming the battery compartment drops below 35 deg when nighttime temps drop to 25 deg. I don't know for sure as there could be residual heat from the day temps, but I would suspect there isn't and it would need to heat the battery.

    I will hope the battery is doing what it is supposed to be doing and I just cannot see the voltage drop as a result.

    Thanks again for the very helpful details.

  • pthomas745
    pthomas745 Administrator, Moderator Posts: 4,700

    The only reason to "have" to heat the battery is if you need to charge the battery if you happen to be in the "below 35 F inside the battery situation". I mentioned the "low temp charging protection" circuit, which would prevent any charging if the internal temps dropped that low.

    2017 Outback
    Towed by 2014 Touareg TDi

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