gen II tracktion battery questions from a 'newbe'

The 12V battery powers up the ECUs prior to the Prius becoming READY. Once the Prius is READY, a DC/DC converter within the inverter converts high voltage DC to 13.8VDC to power the 12V bus and charge the 12V battery.

At that point, you could disconnect and remove the 12V battery and the car would continue to run. Obviously, once the car is made IG-OFF, the car would not be able to be restarted.

The traction battery provides high voltage DC to the inverter. The nominal voltage of that battery is 201.6V (28 modules x 7.2V) but the actual operating voltage is around 220V.

The inverter converts high voltage three-phase AC to high voltage DC and the reverse. Hence, the inverter can receive power from the traction battery and provide charging current to the battery.

The air conditioner compressor and the two motor generators in the transaxle operate on high voltage three-phase AC, from the inverter. There is a voltage boost circuit in the inverter which can provide as much as 500VAC to the motor generators, thus reducing resistance losses.

I suggest that you subscribe to techinfo.toyota.com and read the New Car Features manual to obtain a theory of operations for the various systems within the Prius.

The traction battery life is variable but you can probably expect a service life of at least 180K miles or 12 years (whichever comes first) in your moderate climate.

 

Patrick gave a good answer, so let me carry it a little further. All of the Prius electrics that are common with other cars are 12 volt DC, lights, horns, fans etc. Since the 201 to 12 volt converter in the inverter is always working once Ready, you do not see the voltage fluctuations you see in cars with an alternator, nice steady voltage.

The A/C compressor, and the two Motor/Generators are AC, and the Inverter makes the voltage they need at that moment, only the HV battery is really running at 201 volt DC

Special Issue: Inside the Toyota Prius: Part 5 - Inverter/converter is Prius' power broker | EE Times

Here is the 'low power' side of the inverter

 

Hello from South King County Wa. I hav a 2005 Prius purchased locally. My HV battery failed two months ago at 100,500 miles. I am told this is highly unusual, however even with 4 hybrids in the family from the same dealer they offered no price concession - $3300 to replace. Thank you Toyota :|

The lesson I learned was to be prepared...know your options. I hadn't investigated the HV replacement options at all as the general concensus is the battery pack typically last ~200,000 miles. With your skills I suspect pulling the pack and replacing the bad modules(s) would be quite doable. For me, I would have liked to have that work done. But when the pack fails (one bad module in my case) there isnt much time to read up on the options.

By the way, the only 'warning' I had was a sudden drop in my mileage to about 37 combined from a consistant 45 for the years prior. At the time I chalked it up to the standing water on the streets. Within two weeks the dash suddenly lit up like a christmas tree.

 

Do not confuse the dealer with Toyota. The dealer will not take the loss, Toyota may. Many folks take their case to Toyota Regional and get steep discounts on parts (not labor).

Here is good advice and important phone numbers and mailing addresses.
The Right Way to Get Your Issue Resolved - Toyota Customer Service Tips

 

A great deal of my understanding of the Prius comes from Hobbit's site
Hobbit's techie-rants

That will keep you busy for months.

 

Jimbo, I appreciate you input and link. All the best.