Battery Boosters

No. If the 12v battery is dead, the 12v outlets will be disconnected. They come alive in the IG-ON mode or the READY mode (can't remember which). So with the outlets out of the circuit, there's no way to backfeed the 12v system.

 

Bob Stan,

Without some modification, what firepa63 says is true. In the
stock configuration, the two 12 power ports are activated by one of the
CPUs. But the CPU needs 12v power to boot up.

However, there is a work-around. Here's the shaggy dog story:

http://priuschat.com/forums/prius-technical-discussion/42651-dead-12v-battery-glove-box-remedy.html

Hope this helps.

 

Bob,
You have choices other than the "easy" rewiring of one of the auxiliary power plugs to stay on (there are two). You can also jump the 12v battery from either the designated terminal in the engine compartment (see your owners guide) or by a direct connection to the battery in the "boot" (British speak). Just be very careful to get the polarity correct as reversing the booster leads can result in an expensive repair.

You Prius can pull a significant current when first attached to the boosting source to start charging the little 12v battery so wait a while before pressing the power button to let this surge die down (then the in-car battery can help as it will be partially charged).

When you press the power button there can be another short, high current (~30A), load to run the brake boost pump so the boosting battery needs to be able to supply that as well (so much for some discussions about using flashlight batteries to start a Prius).

When I travel I have a small booster in the trunk, but the several times I have used it was to help others with their dead batteries. My 2004 Prius with 145,500 miles still has the original battery, but it has never been accidentally drained.

JeffD

ps: you can perform a simple health test of your 12v battery. A description of the procedure is available at: Checking 12v Battery Health - Hybrid Car Forums