Community Forums

RV Vagabond · 03-24-2025, 06:25 PM

In my Class A, my batteries can put out up to about 180 amps. When I run my microwave oven, it normally uses up to 160 amps, including all other amp needs for ongoing normal things. But lately and at random times it seems, it will suddenly jump up another 80 amps, showing for a second 240 amps which trips the breaker and cuts power to all 120 volt outlets. But the outage is just for a second then it resets, and then it still shows using 80 amps for about 5 seconds then settles down to its normal 25 amps. Even if it is my residential fridge compressor kicking on, that uses only about 12 amps. This is on an 8 year old Class A, which never did that before a few weeks ago. So I can't see where all those extra 55 amps are coming from. Any ideas?

d23haynes57 · 03-24-2025, 06:35 PM

55 amps DC 12 volt is only 550 watts. Your fridge needing 12 amps AC is 120 amps DC so it could be that surge. Could also be an ice maker or defrost. For the microwave, is a convection oven also and any chance it is turning on the heating element?

SafariBen · 03-24-2025, 07:54 PM

I'd get a Killawatt meter and plug the microwave into that, and on shore power, then see if you can replicate the issue with only the microwave running.

David Pate · 03-24-2025, 09:56 PM

That’s a weird issue! it could be the inverter acting up, especially if it’s older. Sometimes they draw more amps than they should. Could also be something with the fridge or microwave causing a surge. Check for any loose connections too—those can mess with things. Since your batteries are 8 years old, they might not be holding charge well either.

Campfamily · 03-24-2025, 10:11 PM

Electric water heater?

Gary RVRoamer · 03-25-2025, 09:04 AM

An extra 80 amps is less than 1000W, so it could be many things cycling on briefly. Your inverter is only about 85% efficient, so a an extra 120vac load of 700-800 watts could cause the inverter's DC amp draw to jump by 80A. D23haynes suggested several possibilities. You don't have infinite power like at home or even on shore power- you have to carefully manage your power demand when using the inverter.

Tony Ramirez · 03-25-2025, 09:18 AM

Might be the auto defrost cycle of the res fridge, I couldn't figure out why sometimes I would see my inverter putting out 50Amps randomly till I understood the fridge.

There's ways to disable the auto defrost, but I just live w it.

PS89 · 03-25-2025, 01:16 PM

Quote:

Originally Posted by Tony Ramirez

Might be the auto defrost cycle of the res fridge, I couldn't figure out why sometimes I would see my inverter putting out 50Amps randomly till I understood the fridge.

....

Most likely this!!!

RV Vagabond · 03-25-2025, 11:06 PM

Quote:

Originally Posted by Tony Ramirez

Might be the auto defrost cycle of the res fridge, I couldn't figure out why sometimes I would see my inverter putting out 50Amps randomly till I understood the fridge.

There's ways to disable the auto defrost, but I just live w it.

Ok but it only started doing this after everything was 8 years old.

Tony Ramirez · 03-26-2025, 07:11 AM

Quote:

Originally Posted by RV Vagabond

Ok but it only started doing this after everything was 8 years old.

Are you sure it was doing doing it & you didn't notice? Mine does it about twice a day for ~20 mins at a time. Unless I'm looking at the screen @ THAT time, I wouldn't notice. If I go to the history of my shunt, I can see what it's doing.