Chassis Battery Voltage Fluxuating while driving

[ColumL]

Hi Folks, Just bought a used Newmar Dutch Star DP with Freightliner chassis. No issues with inspection or initial drive but within first 25 miles I started to get Low Battery Voltage! warning light and beep. I see the voltage drop and then pop right back up to 13.1. It’s totally intermittent. Only thing running is air conditioning from chassis and Magnum inverter on to power refrigerator. No loose connections that I could tell.

Any ideas?

Thanks in advance for any advice,

Colum

[wa8yxm]

In addition to that I'd have your batteries tested. That low voltage can be caused by the isolator kicking in and out and you have that inverter sucking major amps when the fridge is fridging.

[ColumL]

Good point. The intermittent nature of it made me start to think it could have been linked to when the fridge compressor kicked on. Great insight here. Glad I joined. Thanks and Happy Independence Day!

[grldst]

Sounds like you may have a 160 amp Leece Nevelle alternator. The 200 is a bit better but I know a lot of RVers that had alternator issues by running the fridge of the inverter. Run fridge on propane or switch to a better alternator.

[ColumL]

That makes sense given it was mostly idling while it was inspected and quick test drive. Thank you

[ndrorder]

That is a typical symptom of a voltage regulator overheating and tripping out. Most voltage regulators are built into the alternator. The parts store can test it for free if removed from the engine.

[ColumL]

Thank you. I’ll have battery checked. Figured if it was alternator I’d rundown juice in the batteries completely, but if it’s not the batteries I’ll look there next.

[Flute_Man]

You might have a bad battery, loose connections, or a bad alternator. By the way if the refrigerator has 12 V it will run on propane just fine. The inverter should not be needed to run the refrigerator.