Battery failure due to years in use or mileage?

I was going to ask about running out of gas and forgot; I'm glad you mentioned it! I learned about the battery discharging the hard way. I had never run out of gas in my life until my step-daughter decided to return the car so empty that I ran out of gas before getting to the gas station. I had no idea that the battery would completely discharge after gas had run out, until it did! How much damage does that do? That is a good point to consider in purchasing, along with all the others. I know one thing I consider from these threads is what kind of climate the prior owner(s) lived in.

 

Just for the record, I have nearly 14 year old 2004 Prius with 280,000 miles. I am amazed that the pack is in relatively decent shape. I still average around 45 mpg overall. Amazing car.

 

I just bought a 2004, with 220k on it. After driving it around monitoring the battery level, I thought the hybrid battery had to have been replaced at some point since it had so much capacity and power.

Well turns out, I check all of the records, always serviced at Toyota it's whole life, and no record of the battery ever being touched. Well I thought maybe the battery had been replaced 3rd party. A week later I took apart the rear hatch area to replace the 12v battery, so I decided to look for signs of replacement. NOT one bolt had been turned and even some cob webs were down there on the high voltage service connection. All original! Theses 2004 were tanks!

 

I wish we knew the data about Prius batt life. But the hidden story ain't too bad, we can safely say.

 

Since Toyota won't say anything other than "designed to last the life of the car," we have to rely on what 3rd party information we can access. That information can be found in one article by Consumer Reports, and in the ongoing descriptions on True Delta and here. And while it's not perfect, the data we can access to date confirms Toyota's stance for 85% or more of owners that they'll never need to replace the battery while they own the car.

I think it also says something positive about the car that among the 3-15% who did experience a failed battery, it seems a substantial proportion liked the car enough that they're willing to spend the thousands of dollars it takes to replace it just so they can continue to drive a Prius.

 

I have not seen the Toyota quote on 85% owners not needing to replace...have you posted that reference? That would be new information to me. A certain % of those would be covered udner warranty. I can accept 15% of 2006 batts gone bad, that's sounds reasonable.

The old stance was less than 1% of Prius batts gone bad, which is less useful as that includes alot of new Prii. Also it's probably much greater than 1% now.

 

Sorry, I wasn't very clear. I meant from the statistics we have available, 85% or more of Prius batteries have verified the Toyota stance that they last for the life of the car

 

Just to clarify, not while the car is off. The HV battery is totally isolated when the car is off.

There is also no reason a HV battery in a reasonable state cannot sit in stasis for a good period of time. There is self discharge, but as long as the HV battery is in reasonable shape, each module shouldn't go much below 7.2 V.

 

I have a 2005 Prius with 65 k km or 40 K miles. I bought from Germany 5 months ago. The small battery was original in place with some glue like a resin, I had replaced for my peace even had 12 to 12.1 V under zero C degree. It was very hard to remove the screw from the ground, nobody touched the screws, so I assume also the HV battery as the owner said it is original factory. To remove the HV battery must to remove first the small 12 V one. HV screws look nice without trace of tools, untouched. As the city of the (only one) owner it's flat terrain and according with service book, compared with Toyota records, the car was driven almost daily at an monthly average of 5000 km or 3.11 K miles, could be near end of life the HV battery? I checked by mini VCI cable and software, the Delta SOC it's zero, the voltage difference its near 0.2 V near 2 purple bars and 0.11 V with 6 blue bars. The problem it is: I left my car sit without driving for 5 weeks with the first green bar. I should see a big difference after 5 weeks? I have to leave my car 5 weeks, drive 1 month and again like a rota. I'll post here the next measurements.

 

So congratulations! That mean I'm not alone with my 2005 Prius HV untouched.

 

Sorry, yearly average, 5000 km per year!!!

 

So after 65 days unused, I found my Prius in the same condition as I left it, with the first green bar. The small 12 v Battery founded full because has been connected with a small solar panel.

 

congrats!