2005 Prius 12V Battery Questions

The numbers for your battery could be interpreted a couple of different ways.

If they come from the MFD test when the car has set over night, the battery is getting weak. Possibly need replacing before next winter.

On the other hand if the test was ran just after you shut down the Prius, then the battery probably needs to be replaced ASAP.

Low air pressure in the tires would definitely account for the low MPG, plus short trips don't help either.

Best of luck to you!

 

Given that he lives in Florida, summer is a LOT more stressful on the battery than winter.
Since the battery is about 7 years old, I suggest replacing it soon.
The numbers definitely indicate a weak battery........or a meter that is out of calibration.

 

I would say you are in need of replacement. I would imagine you are on the second battery. A 2005 Prius battery would be approximately nine to ten years of age if it were original. Most don't last much longer than five or six years in a Prius.

It would be a good idea to replace it before it fails. The Prius really doesn't give a warning like slow cranking on other car's. Most of the time when they fail, you are pretty much dead in the water and sometimes can't even jump them.

One hour job if you are mechanically inclined. Plenty of info here on Prius Chat on how to change it. Link in my signature below from when I did mine - Post #8 in that string.

Best of luck to you!

 

Plenty of opinions on that one. And they go both ways. When I did ours, I went with the battery from Toyota. Too soon to tell on it, but so far so good. At least mine was fully charged when I bought it. Have seen a lot of posts recently about Optima's sitting on shelves for long periods of time before being sold and will not charge back up fully. FWIW, I am a old school type. Daddy taught me that original equipment is best and what is designed for that application. Other's will disagree and say that aftermarket at times is advanced. .

Remember opinion are just that, opinions. Everyone has one. It is really up to you what you buy. Both batteries will do the job as long as you get the right one.

Best of luck to you!

 

if your curious, the label has a date code which can be interpreted by some here.

 

I would verify with Advance Auto Parts that they will do a Prius 12 volt for free. It is not the easiest battery in the world to put in. But it can be done by anyone including you if you have the tools. Doesn't take a lot of tools either.

Before you pay someone to put it in, take the time to watch this video.

Best of luck to you and let us know how it is all works out in the end.

 

In my opinion, neither.
You need an AGM style battery from a "name brand" company.
I've never had a problem with an Interstate battery; even the Diehards from Sears seem to be good.
If it would be more convenient for some reason, go for the OEM; I think the Optima's are over priced and over-hyped but that is just a gut feeling.

 

P.S. Easy Rider, I'm a she, lol.
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Sorry. I'm old enough that "he" was the accepted generic term when one didn't really know the gender.
In this case, I should have known better.......given the screen name.

 

Please do.
There are some safety concerns with both operations.

With the battery, disconnect the NEGATIVE post first and keep it disconnected until ALL of the other work is done and then re-connect it last.

I'm not sure I'd recommend anybody do their own seatbelts these days.
Most have a "pre-tensioner" which is operated by a blank gun shell.....really.

Good luck. Hope it all goes well.

 

I hope that you bought high quality tools. The sockets should be six-point (not 12-point) if you are going to do work on the seat belt fasteners which are torqued pretty tight, 31 ft.-lb. A cheap 12-point socket may round off the hex edges of the nut.

The 12V battery installation will require box/open end wrenches as well as socket wrenches. You'll use the 10, 12 and possibly 14 mm sizes. Good luck with that.

 

I highly recommend the Exide AGM or OEM. I am in Tampa, I have a wholesale account and can pick either one up for you if you like and install it for you no charge.

PM if you need help.

 

Princess9483,

If you have access to a 110 volt outlet whereas you could plug in a battery charger to charge your battery in your Prius, I would suggest to you to invest in a good "smart charger" that is designed for AGM type batteries. If you keep your 12 volt fully charged it will last you a lot longer than simply relying on the charging system that is built into the Prius.

Best of luck to you.

 

To be honest I don't think those numbers are low enough to cause any serious problem or any noticeable reduction in MPG. Any increase that you're noticing with the new battery is probably due to one of either changed driving habits (thinking more about fuel economy) or driving conditions or just random variations.

 

Those numbers ARE indicative of a battery that is getting weak.

Whether or not it was bad enough to cause engine problems is a matter of speculation but others HAVE reported that weak batteries have caused engine faults and so did he. What's the point of questioning his reported results now ??