[FIXIT]

got my new 2004 for just over two weeks now. 8)

:?: While the Prius Electric Motor batteries are warranted for a long time, does anyone know if they weaken notacably with age B4 the expiration of the warranty period.

:arrow: Also, there is an auxiliary battery issue with the old Prius. Is the battery placed in the 04 spec'd differently so as to last longer than the year and a half to two years that the I understand the older ones provided at best?

 

[mrv]

age on the 12v battery depends on how well
you treat it.

I've drained my 12v battery once on my 2001 (husband left the headlights on for a few hours), but
thankfully I didn't need a jumpstart for that occasion (just got a white screen, eventually the car turned itself on, just enough juice left...)
However, I'm just past my 3-year anniversary with my 2001, still on the original batteries...

you really only need to replace the
12v battery if you mistreat it (run it
down and don't fix the situation quickly, or
run it down often). However, the
12v battery is still smaller in a
2004 Prius compared to a "traditional" car,
so it's still easier to run it down
(by leaving lights on overnight, say by leaving a door open)
on a Prius than on a regular auto.

 

[Phoenix]

12v Battery Replacement

Has anyone replace the 12v battery? How much is the OEM battery? Also, can you use one of the larger sealed batteries that can be mounted in any position (will they fit, any problems with charging system, etc.)?

 

[RSnyder]

I've got over 75K miles on my 3.5 year old 2001 Prius and the original 12-volt battery is still working fine. It even made it through some fairly cold days this winter (near 0 deg. F). The high voltage battery is also working fine. I have not noticed any difference in performance from when it was new (but that was long ago, so it would have to be a pretty big change for me to notice).

 

[Phoenix]

Battery Replacement

The thing I am worried about is the heat. Down here in Phoenix, most auto batteries only last about two or three years. In the 35 years we've lived here, I have had only one battery that lasted over three years.

 

[Henry]

Since the Prius 12v battery is not in the engine compartment, mechanical-source heat should not cause a problem. Of course, on those 120+degree AZ days.....park it in the shade!

 

[Phoenix]

Replacement Battery

Good tip -- parking out of the sun -- but cacti don't provide very much shade. However, the short 12v battery life has a good trade off; Arizona cars don't rust. And, we don't slip and slide into each other in parking lots in the winter.