Gen II Prius HV battery dying at 78k?

I do anywhere from 3-4 battery repairs/rebuilds a week at my shop. I've seen them fail around 80k but the car was a 2004. What I'm starting to see is that it's not just mileage that can cause a failure but time, 8-10 years.this is just from my experience I could be wrong

 

Do you mean the ones you rebuild fail at around 80K. If you mean all original factory batteries fail at 80K. Most Prius HV batteries last far far longer than that. I have 170K on mine. 2fas4u(sp?) had like 590K miles on his before he traded it in on a gen III and it had the original battery.

 

This really depends how long you intend to keep your car. If you think you will keep it for another 8 years or more, a new battery from Toyota isn't a bad idea. Your car has low miles so it should easily go another 8 years (which will bring you to about 160k miles).

A rebuilt battery will never be as reliable as a new battery. you may have to rebuild it several times to get another 8 years from it.

 

I agree with ToyoWorks . My 06 Prius has 89,000 miles and the traction battery is swinging low to high charge more and more. I suspect you could get 200,000 plus miles in 8 to 10 years on the battery or less than 100,000 if you're a low mileage Prius driver like me. Time is a factor.

 

The majority of '04 (including the high mileage ones) still have their original traction battery. There's a light uptick in failure rates in climates where there are extreme high temperatures like Arizona.

 

Yeah, these older Priuses (8 to 10 years) still probably have a lot of cycles (charge/discharge) on them, even if they don't have relatively high miles.

What you find with lower mileage cars is that they've generally done just as many (often more) trips than high mileage ones, just much shorter trips. Cold starts tend to hammer the battery a bit (people often report rapid drop of SOC in the first few minutes), whereas long highway cruises tend not to work the battery very hard at all (provided it doesn't involve mountain passes). So it's probably not all that surprising that many lower mileage batteries are still aging similar to their higher mileage cousins.

 

No it's not common to see a battery with that low of mileage to have a failure. My traction battery on my personal prius went out at 203k before needing a rebuild.my car is an 04"

 

It's harder on NiMh cells to sit unused than to be driven daily (or at least 5 days a week). Any car that sits for more than 2-3 days at a time is a perfect candidate for one of our grid charger's to easily keep the cells topped and balanced. It also works as a PHEV charger, although a slow one

 

What are the chemistry details of the cause of this? My '09 sits often for two weeks between trips. I see no drop in SOC over that length of time.

 

Messages you very interested in more info on the charger

 

Well, I am a CPA by day, not a chemist, but there is some good info out there. Self-Discharge of NiMh cells is even worse in the low resistance NiMh cells used in our hybrid vehicles as they are designed to give their charge easily. When we stomp on the accelerator at a green light, we want power right away

Here's some reading that might help:
Self-discharge - Wikipedia, the free encyclopedia
and
Nickel–metal hydride battery - Wikipedia, the free encyclopedia

The reason you don't see a change on your dash SOC when re-starting the car is that the car does not recalibrate to the current charge level of the hybrid battery each time the car is powered on. The vehicle has no concept of elapsed time when powered off. You could turn the car off for 10 years, then turn it back on, and it would display the charge same level from when it was powered off 10 years ago even though the battery would effectively be at zero SOC.

 

Thanks for the update tonymark. Since you're planning on keeping the Prius for some time then I don't think you can beat going with a new battery.

 

I have a CARB 06 purchased in CA, now in AZ. If I ever have a battery issue, for that $, it's going back to CA on a truck & be re-registered for the 10 year warranty.

 

There you go, I fixed it for you.