Tri Pac APU shuts off 30 Minutes and gives error When using Invertor

I may be wrong but it sounds like you are using too much of the inverter's capacity, which causes it to work too hard, get hot, and shut down. The number and capacity of truck batteries will affect how long the inverter can run.

What is the power rating or watts the inverter says it can power? Typically the inverter or the manual that came with inverter will say 1000/1500 watts, or whatever the actual numbers are. In this example those numbers mean the continuous or running watts/peak or surge watts.

Try starting your truck engine before and during the time you power your microwave. Of the 3 devices, that is probably the most power hungry. Or try a test where you shut off your TV and microwave and only run the fridge and note if the inverter will run longer than 20-30 minutes. I'm suspecting your inverter doesn't provide enough watts to power all of your stuff at the same time. Also, don't turn on multiple items at nearly the same time. Turn one on, wait a minute or two, and power on something else. If you are using almost all of the inverter capacity the power surges may be exceeding the peak rating.

 

why arent you running 4 batterys

 

Sounds like you are overloading it with too much big stuff.

Electricity in a inverter creates heat that has to be vented. Too much loading or "Pulling" on a inverter cooks it every time, at some point in that time frame it must fuse off to protect itself from thermal destruction.

 

You may need to replace the inverter. It sounds like it is drawing an excessive amount of current while idle, a good indication of a breakdown in the works.

 

I've run a tv, microwave, fridge off of a 2000w inverter on a tripac, never had an issue. If your APU is a tripac, a bad or too small inverter won't shut down the APU, the inverter will overload and shut down, but the APU will still run. It may be a bad or weak alternator on the APU that can't keep up with using a microwave. A normal 120v fridge doesn't take much power once it's running, it's biggest draw is on the startup of the compressor, and I have run a dvd player and 27" flatscreen off of a plug in inverter, so it doesn't take a lot of power either.