Using bed outlet with engine off only works for an hour before ignition mode turns off?

I am searched for an answer to this specific question and cannot find it. I just bought an iceco fridge and plan on using the bed outlet to power it. This works on my first trip except when the engine is off, the ignition mode only stays on for about an hour before it shuts off. So I have to push the engine on button every hour to reset to ignition mode. Accessory mode won’t power the rear outlet. I’ve read posts here and the manual- nothing says the ignition mode should turn off after an hour. Ideas? Looks like I’m buying a jackery….

 

You’re better off using a Jackery or other battery.

first, you won’t get yourself stranded when you kill your starter battery.

second, you’re wasting energy converting DC (battery) to AC with the inverter, and then the fridge converts back to DC internally.

lastly, you’re powering more than just the inverter/fridge while on ignition mode. I don’t have a third gen, but I would guess that the fuel pump and many other things are running, not wasting more battery capacity as well as unnecessarily being powered.