Which battery is which?

[Kidd]

Is the battery that's hidden in the rear hatch area the battery that is being charged on the MFD?

[Betelgeuse]

Originally Posted by Kidd

Is the battery that's hidden in the rear hatch area the battery that is being charged on the MFD?

Well, both batteries are hidden in the rear hatch area. The battery that's being charged on the MFD is the traction battery, which is under the rear seat and in the front of the cargo area (i.e. the part closest to the front of the car).

The auxiliary (12V) battery, which is the one that starts the car, runs the lights, powers the radio, etc. is hidden in the back of cargo area on the right hand (passenger's) side.

The 12V battery looks a lot like a smaller version of the batteries you're used to seeing in cars; the traction (~200V) battery is much larger.

[Kidd]

Duh ! I guess I did know that. I must have lost a few more brain cells than I thought, last night! I did not know that the 12 volt handled the radio and junk. What else does the 12 volt run?

[FL_Prius_Driver]

The 12V battery/bus runs everything except the two Motor/Generators, and the air conditioner.

[diamondlarry]

Originally Posted by Betelgeuse

The auxiliary (12V) battery, which is the one that starts the car, runs the lights, powers the radio, etc. is hidden in the back of cargo area on the right hand (passenger's) side.

I thought it was the traction battery that actually starts the engine and the 12V was responsible for the computers, lights, etc.?

[patsparks]

The 12 volt battery runs very little really, only filling in where the inverter falls short, it fires up the inverter and computers then the inverter takes over. The battery smoothes the power supply during peaks in demand and powers accessories when not in the ready mode such as the interior lights and radio. It also powers the headlights if they are on after the system is shut down until the door is opened. It powers the security system also.

I would say the traction battery is behind rather than under the back seat. The petrol tank is under the floor under the back seat.

[Betelgeuse]

Originally Posted by patsparks

The 12 volt battery runs very little really, only filling in where the inverter falls short, it fires up the inverter and computers then the inverter takes over. The battery smoothes the power supply during peaks in demand and powers accessories when not in the ready mode such as the interior lights and radio. It also powers the headlights if they are on after the system is shut down until the door is opened. It powers the security system also.

I have always been under the impression that the 12V battery runs everything but the drive motors and the A/C. Perhaps you're refering to the fact that the traction battery charges the 12V battery when the car is in "Ready"? Here's a question that I don't know the answer to: if you were to disconnect the 12V batter while the car was in "Ready," would the headlights and the radio continue to work?

[FL_Prius_Driver]

Originally Posted by Betelgeuse

I have always been under the impression that the 12V battery runs everything but the drive motors and the A/C. Perhaps you're refering to the fact that the traction battery charges the 12V battery when the car is in "Ready"? Here's a question that I don't know the answer to: if you were to disconnect the 12V batter while the car was in "Ready," would the headlights and the radio continue to work?

This experiment was done. Go to:

http://techno-fandom.org/~hobbit/cars/prius-12V/

[Betelgeuse]

Originally Posted by FL_Prius_Driver

This experiment was done. Go to:

http://techno-fandom.org/~hobbit/cars/prius-12V/

Cool. Thanks. So, I guess this means that pat is right; nothing runs off of the 12V battery while the car is in "Ready." The DC-DC converter directly powers everything while the car is on.

[KMO]

Originally Posted by Betelgeuse

Cool. Thanks. So, I guess this means that pat is right; nothing runs off of the 12V battery while the car is in "Ready." The DC-DC converter directly powers everything while the car is on.

The same is true of most cars - you can usually disconnect the 12V battery while the car is running. While running, the 12V power is generated by the drive system - the alternator on a normal car, or the 200V hybrid system on a Prius.