Hello. I had a bit of an odd occurrence today and wanted to get some input from some fellow Prius owners who are more knowledgable about cars than me. (98% of you). I have an '08 Prius with just under 100k miles on it. (Yes, I've been busy). So I've had the original 12v battery now for 5 years. This morning the car wouldn't do anything, like the battery was dead. I jumped it and as soon as I connected the black wire to ground the car fired right up. Like, immediately.I drove it a short distance and parked it. I put the screen into diagnostics mode and watched the voltage on the battery for around 5 minutes and it didn't seem to be going down, voltage seemed to be holding. So tomorrow morning I will try it again after it sits overnight to see if it starts without any problems. My question is I had my local advance auto parts order a battery that should be in tomorrow. The cost was a bit high ($220) but with 5 years on the battery and what happened, should I pick up the battery and replace it, or not? Is what happened today a sign that the battery is probably bad, or does it immediately starting when jumped and holding a charge suggest that there could be some other problem that had prevented it from starting?
Five years is a good long life for a 12 volt car battery in any car. I hope you got a AGM battery with external venting and JIS posts. That will be the safest and easiest to install. If you are in the US, two batteries that are known to be designed for a Prius are: DS46B24R YELLOWTOP® Prius® Auxiliary Battery 8171-767 :: OPTIMA® Batteries and Exide AGM Car Battery (Group S46B24R)
I would just get it replaced. 5 years is a good run, and it's making ominous symptoms. You can get more involved, with a multimeter to (rudimentary) monitor it's status, and a low amperage intelligent charger, to keep it in good shape. Also helps to just live without as many of the convenience lights as possible, and auto headlights with their delayed shut off. Personally, I do all of the above, and replace it every four years, regardless of how it's doing, just treat it like a regular maintenance item.
