Typical lifetime of 12V battery...

I'm still on the original battery for our 2006, with 70,000 miles.

Service life will vary a lot depending on heat, driving patterns, and how many times you flatten the battery by doing something dumb.

As a general guess, I would say that the average Gen II Prius 12V battery lasts for about four to six years.

Tom

 

The 2nd battery lasted a couple months, maybe 10 weeks. The original battery was replaced the 1st time the car wouldn't start around 3 1/4 years.

 

The expected life of our 12v batteries id dependent on how they are treated. In my 2004 Prius the battery was still functional at 200,000 miles and 8 years when I finally replaced it with an Optima Yellow Top (20,000 miles ago).

I attribute its long service life to:
1 - It was never drained to zero. Partly due to care and good luck I guess
2 - I tend to take longer trips and run up the miles. This gives the Prius plenty time to slowly charge the 12v battery.

JeffD

 

04, 95,000 miles, original battery. 08, 30,000 miles, original battery.

 

Anything longer than 4 years is pure luck. I suppose you can choose to drive on bald tires, too, but why risk it?

 

Similar story but

1, I did drain my battery a time or two.
2, I didn't drive long trips much

My 2005 had about 6 years and 75K miles when it first showed signs it needed to be replaced (do not know, I am the second owner it may have given the first owner signs as well). I finally replaced it at 7 years and 85K miles after using a battery charger for a year. Miles and years are rough estimates.

I'd say the original battery is worth changing by no later than the 5 year mark assuming you get the optima for $150 or close to that, or get a dealer battery for a similar price. Unless you just enjoy playing with voltage meters and battery chargers.

 

Not pure luck.

Statistics. And how the battery was used.

Original battery in my 05 - 7 years old this month.

168K miles - mostly highway - mostly driven in rust belt states.

I'm sure that many Gen 2 owners have similar longevity on their auxilliary batteries as well.

 

Original battery on 2006 with 68k miles.

 

The 'problem' with the Prius battery is not the battery, it is us.

We all 'know' when a battery is going bad, it makes this slow grinding noise while starting. The 12 volt battery in the Prius never attempts to start the engine, so we are blindsided because we ignored the other symptoms, waiting for one it will not make.

I do not claim that your battery will die at 4 years, only that you should begin each troubleshooting session with "Could this be a dying 12 volt battery?" after 4 years.

 

I'm doing the 60K service at 71K on my wife's 2007. The car is hooked up to the Scangauge II. The VLT gauge reads about 13.4 when the car is running. Any suggestions on what other SC or X functions I could look at to get an idea of the 12volt health?
Ed

 

I have both an 05 and an 06. Wifes car is the 05 and she left lights on in the car and killed the battery at least 6 times. Her battery lasted 5 years. I have an 06 never left the lights on but would listen to the radio often while sitting. My battery lasted 3 years. Go figure!
-Paul R. Haller-

 

When the car is running, you are really measuring the inverter output, not the basic battery level. Check VLT after the car has been sitting off overnight, or at least several hours, and before turning the car on.

It would be best to check VLT without opening the driver door. Opening the door fires up the brake accumulator, which depresses the battery level by a few tenths of a volt. But most of the numbers posted here are just after opening the door, so it can still be used as a reference point.

 

2008 at 110K - looks like I've got low battery - had the Master warning/vsc/check engine/brake no acceleration issue going on...dropping the car at Toyota tomorrow...

 

Just lost my very well cared for original 2007 battery. 5 years old this month. Battery tended every month. Let the wife drive it 3 weeks straight then one day went to fill it up and checked the mfd and it was 10 volts She swears she didn't leave the light on in the car.....

Just bought an Optima Yellow Top today the DS46B24R the correct pencil post from Advance Auto.
$199 plus 15% off picked up right at the store with $50 Gift certificate next time I spend $100 there.
Its a drop in.

 

More importantly read volt under acc load. That gives you true capacity. First thing in the am before starting the car .
Push start button once without foot on brake. Wait a few seconds and push the button again without foot on brake. Thats accessory mode. Read VLT. Anything below 12 volts is highly suspect to leave you stranded someday.
Unless you monitoring its slow death.

 

Statistics show that a few, but not many, last longer than designed. Read any any battery manufacturer's warranty. 48-60 months max. Batteries work by chemical reaction/decomposition. Theories such as yours are causing too many owners angst.

 

Reeeaaally, kenoarto? Did you check first with the friendly folks at Optima before making such an outlandish claim?

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And Wth is your point, here? If anything, I'm making others jealous, not anxious by getting 7+ years out of the OEM aux battery. 90 months and still working like day 1. ​