Frequent engine starts for hybrid battery charging during stationary use

Try setting it in eco mode.

 

No. The battery charging algorithm when not moving is to partially recharge the battery causing frequent engine cycling. The first off time cycle is much longer since the hybrid battery is more fully charged.

In cold weather there is a second set of logic that attempts to keep the coolant slightly warm so the heater works.

The reality is car camping will run the engine frequently and is bad for the engine due to constant thermal cycling, especially with a gen3.

Toyota Europe put out a tsb that warned about operation like this as a possible contributor to head gasket failure. When the engine stops, the water pump also stops. This leads to uneven cooling of the engine. In addition, ten minute or longer cycles of engine off in the winter cools the engine by 30-50f only to have it heat up again when it restarts.

This type of operation is considered a severe driving condition. I might consider it in an emergency when stranded or to power an inverter to feed a furnace during a power failure but not as a camping or living solution.

 

What are your climate settings? They can make a big difference. You might check out this thread, down as far as the 'hunker extender' idea:

on hunkering, Gen 3 style | PriusChat

 

If you put it in Maintenance Mode, the engine idles continuously. However, I'm not sure whether it keeps the hybrid battery charged in that situation, so check that important detail before trying Maintenance Mode.