Dead 2006 Prius

Ok, the 12V battery supplies power to all the computers (ecu's) that control everything on the car- if that battery is bad or discharged (dead) then the car won't work.

Normally when you press the power button (with foot on the brake) the various computers will "boot up". If they have no problems then one ecu will allow relays to connect the High Voltage battery to the inverter assembly. The inverter handles power flow back and forth between the 2 electric motors in the transmission and the HV battery. (It also has a voltage converter that supplies around 14V to charge the 12V battery and power all lights, accessories, and other low voltage stuff).

When the gasoline engine is needed, the inverter uses power from the HV battery to spin the MG1 motor- which goes through gears to rotate the engine. There is no "starter".

Whenever the car is "on" and has the green "ready" light- that is the hybrid system it powered up and the converter is supplying 14V. They don't want you trying to "jump start" or boost the Prius under that condition (which it don't need anyway). Any other state (such as being "dead") is ok to try and boost.

Ideally you would measure voltage at the underhood jump point with a digital multimeter, and if it's low (fully charged with everything off is 12.6V or so) then connect a charger to recharge slowly.

Posted via the PriusChat mobile app.

 

Charge slow or whatever from the front, much safer for the car than the back where confusion can lead to burnt up parts if the battery is charged in reverse or installed backward. Some will say use an advanced charger like a four stage battery tender in case confusion causes you to leave a single stage old school charger on for days at a time.