2026 Prius Plug in won't start

The idle power draw is around 500 W. This is without the A/C/heat pump running, but with the lights on. I certainly see my SOC drop by 1% at idle for my Gen 4 Prius Prime PHEV every five to ten minutes when the A/C/heat pump isn’t running. It is very wasteful to the environment to leave the car in the READY mode. It is dangerous, too, if the gas engine kicks in and fills the house with carbon monoxide. Just get a Noco Genius.

 

The current Prime, fully charged, can sit in Ready mode for a very long time without running the engine. I have camped, overnight in my 2024 car, heat on set at 18C, in close to freezing outdoor temperatures, without running the engine. This was about 8 hours.

I don’t really like the hassle of plugging in a battery maintainer.

The other solution I like is to unplug the battery sensor on the negative terminal which then charges the battery at 14.4 volts all the time. I plan to do this periodically to fully charge the 12 volt battery. But, most people are afraid to do this.