HV Battery Dying Fast - Need Help, Advice & Options!

My understanding is that inverter failure in the 2nd generation Prius is extremely rare. Inverter pump failure, on the other hand, is extremely common.

 

with no DIY skills and no mechanic you really can trust, maintaining a 200k miles Prius is a risk on your pocket. My advice to you is simply get rid of it and buy a simple car to maintain. There are big ticket items in a high mile Prius that can go kaput anytime. I agree with other people here, the inverter failure is very rare on a Prius. Get the codes and post it here otherwise you'll be spending money on repairs after repairs.

 

On the other hand if you have a friend or family member that works on cars, you aren't going to find many vehicles on the road today that has as extensive of a resource of DIY repair than PriusChat. Anyone with basic car repair skills could learn to fix any Prius problem thanks to this website and its community.

 

Only $1K for that part of the country is a super honest and reasonable price, especially because it was fixed so quickly. They could of spent more time testing the inverter to be sure it wasn't just the inverter pump or ECU, but that would of taken them way more time than just replacing what the error code says was broken and be done with it.

 

congratulations on finding a good, honest Prius mechanic. You might ask him if he’s care to have you give his name and business name here. Seriously. And don’t second guess yourself. He had the car and fixed it. Sounds like a win to me.

 

I don't think you were ripped off. Just because the inverter rarely fails does not mean it never fails. It sounds like you have found a knowledgeable and honest mechanic. The job was done quickly and the cost was very reasonable.

 

I'm still not convinced the inverter was bad, but do understand the tradeoff between testing a part extensively (many hours of billed work) and just changing it.

I don't think though that the inverter pump failing is supposed to ever damage the inverter. The car is supposed to shut itself down before such damage can occur. Jumping the car with polarity reversed can take out the inverter though:

Reverse polarity jump / Fried inverter / 2008 Prius | PriusChat

The OP might want to also check the wiring and plug going to the battery pack fan. Corrosion there (or in at least one case rodent damage) can result in a P0A09 code. Always with P0A08 though, I think. If the OP's car leaks when it rains into the auxiliary battery compartment corrosion at that position is likely. See these threads:

2005 Prius trouble codes P0A08 and P0A09 | PriusChat
https://priuschat.com/threads/gen-2-p0a09-591-the-ol-red-triangle.235257

 

It "stops working" by powering off the inverter if the temperature gets too high. My understanding is that it just won't operate at a temperature so high that it would cause immediate damage. The car can limp along in a pitiful state until the 12V finally discharges below the point at which the car will still run. That might destroy the auxiliary battery as it is a very very deep discharge. I suppose that getting hot enough to throw the code repeatedly might eventually damage the inverter though.

 

glad that your mechanic sorted it out and the repair is not that bad $$-wise. The issue could have been prevented if it wasn't driven longer when the red triangle shows up. As far as I know limp mode will protect the car up only to some extent. Just like overheating in most cars now (engines are made up of aluminum and no temp gauges) it will shutdown the cylinders to cool it off but in reality it can't really cope up with long term usage. The heater coolant valve is also known to fail and leak coolant (a slow leak or a puddle), if this is also not addressed sooner then it can ruin the engine.