When to Replace 12V Battery

go to auto parts store and have them load test it,you should get at least 5 yrs out of the battery

 

In my opinion, it's applied philosophy.

With a Prius, since the 12 volt is what boots the entire vehicle up, and the Prius doesn't have a traditional ignition start, the symptoms of a failing battery are outwardly going to appear to be much more binary than with a regular vehicle. You won't get the slow to turn over "crank".

Therefore some people in an effort to avoid any problems, simply replace their 12 volt battery based on chronological time passed, as opposed to waiting for gremlin like symptoms or worse, the day The Prius doesn't boot up.

4 years?

Again opinion, but I think that's a comfortable cushion as far as getting "value" for 4 years of usage, but replacing before it becomes an issue. It could have a year, or two...maybe even more, life left, BUT....at this point it is becomes suspect. I would actually let budget be my guide, if you can afford the luxury of simply replacing (perhaps early) the battery to avoid problems? Then I think 4 years+, is a arguably viable timeline. If replacing the battery is an economic hardship or significant sacrifice? You could have years left, therefore you could continue to use it, and simply wait until "testing" becomes unnecessary because the symptoms are obvious.

Also IMO but if you have suffered no symptoms of battery failure, then with a chemical based component like a battery, trying to predict it's end of life "span" is very difficult. You could test it today and have it pass, and it could be failing in a month. IMO after 4 years, a voltage test today, only tells you what amps it is producing...today. And that really isn't necessarily a good predictor of how much life it may or may not have going forward.

Therefore, I would simply embrace an operating philosophy, and then don't look back. If you don't want to deal with voltage tests, battery minders and chargers, and/or the simple worry of impending failure than a 4 year time table is an acceptable if conservative choice.

 

I am leaving in a few minutes for my 50,000 mile/4 year service. I am getting the battery replaced. I think there are some things that you don't wait to break before replacing them. Four years is good enough.

 

Dimming lights (dome, interior, marker (side), headlamps), flakey SKS (if equipped), low voltage (<12), are all indicators of the 12V Aux-Bat being on its way out). I noticed all those symptoms on my 2009 Gen II nearly a year ago, so the battery was about five or six years old - replaced it and all was fine! - Good luck!

 

my 2012 is 4 1/2 years old. the battery still reads 12.7 volts when cold, but i have never drained it.
i likely won't replace it for 7 or 8 years. everyone's situation is different and you have to do what's best for you.
if i were concerned about my battery, yes, i would replace it before winter.

 

A lot of it is risk tolerance. As an analogy: are you a 100% equity person, or more comfortable with a balanced portfolio. If you're cautious, I would at least start making overtures towards doing the deed, and it sounds like that's what you're doing.

I think the Canadian Tire Exides are the way to go. I went with a mail order Optima for ours, but recently, had a very positive experience, replacing our son's 06 Civic Hybrid 12 volt. The Exide was physically identical, higher CCA, and showed as in-the-pink with with CT's digital load tester. I later verified with my cheapy Solar BA5.

This one?

MotoMaster Eliminator Ultra AGM Automotive Ba | Canadian Tire

For testing:

Clore Automotive

(they're available on amazon.ca)

 

2010 Prius II owner here. The car build date was July 2009 and the original battery still resides in the back. As @bisco said, I have had no deep draws or drains in 7 years.

Mine still reads 12.7 volts at the post under the hood. I do have a jump pack though, just in case. And as soon as the use is required, will be getting a replacement battery.

 

All true. It's really equity vs balanced. For example: I've read ambulance companies replace batteries every 2 years. They know they're fine, but do it. Or like oil changes: likely lots of life still in it, but you change it.

 

If you have a jump pack with you at all times, you could use the 12v battery till it fails. It's super easy to jump the Prius from the under hood jump terminal.

If you don't have a jump pack, or jumper cables, it isn't easy to predict when the battery will leave you stranded. Our 12v battery was pretty normal till it wouldn't start the Prius one day.

Edit: The OP was correct in stating that measuring voltage of the battery isn't a foolproof way to detect a failing battery. Ours measured 12.7v, but couldn't even operate the SKS to open the door. If one of the cells fails, then you will be able to measure a lower voltage.

 

I believe it does, here's a Camry Hybrid Owner's comment:



It seems to me they're "on it", no cowboy "this is close enuf" stuff.

 

i'm all in cd's.

 

7-9 years isn't too shabby. and supposedly, they conk out earlier in warm climates, where there is a lot of heat build in inside the parked car.

 

Would like to keep the 12v battery as long as possible, so planning on getting a Portable Jumper (like an Anker, only $50) in a couple years to stash in my car just in case.

One of the reason's why I came up with that hackneyed plan to keep an open cooler of ice bottles in my car during the summer...

 

It isn't just the battery failing, it is all the weird stuff that accompanies it.

 

I bought a couple Stanley Simple Start booster packs last night to keep in our Prii, but the cables aren't long enough to reach the two posts. Ate there any extenders, or should I take these back and get something else? They were on sale at Walmart for $20. (Normally $45)

Posted via the PriusChat mobile app.

 

What two posts? Jump at the under hood positive jump point in the engine fusebox and ground using a bolt in the engine compartment.

 

The positive terminal in the fuse box on one side of the engine, and the recommended ground post is on the other side of the engine....A span of approximately 40". The cable/clamps supplied with the booster pack reach a maximum of 30" apart. On any other car I would feel comfortable choosing an alternate ground point. But on the Prius, I'm a bit reluctant to do so.

Posted via the PriusChat mobile app.