In browsing this forum I notice that it does not take to much to discharge the small 12V starter battery. What is the life expectancy of this battery? In my experience in a non-hybrid vehicle the battery should last 3-5 years. Granted, the Prius 12V battery is only used to get the electronics on and enable the main battery to activate the engine so its load is small and short duration but how long before this battery should be changed out. I live in New England and I would not want to be caught in a cold snap and the battery dies. Testing them does not always tell you the truth and a real cold night could sap it.
I would say the life is quite variable, but your 3-5 years is not a bad estimate. For example my 2001 needed a new one after 4 years. All that can go out the window if the battery is ever completely discharged (by a light left on for example). In a discharged state the battery can suffer greatly, especially in winter. A new car on the dealer's lot can have its battery damaged before the buyer ever sees it. We think that this has happened. If you are handy with a digital voltmeter, you can measure yours at the underhood-charging points when its off. You could get similar info w/o a meter, with the car off, from the 'hidden diagnostic screen'. Not sure I know how to access that in the 2007 though. Yours is in good shape if it says 12.2 or above or thereabouts. Replacement batteries are a bit of an issue because Toyota sells theirs for an awful lot. There are other vented batteries available. Use of an unvented battery in Prius remains somewhat controversial. When this battery is 'on its own', the brake fluid pump can briefly ask for about 30 amps. This is the worst they ever see, unless you add certain accesories
<div class='quotetop'>QUOTE(jamarimutt @ Jun 3 2007, 05:07 PM) [snapback]454635[/snapback]</div> I suspect that as with me, your car is driven nearly every day. And of course, nothing left on over night. I've only got a little over 49,000 miles on mine, but don't doubt that it should last another year or more. Dave M.
I began to have trouble with my 12 vdc battery less than a year after purchasing the car. I attribute most of the trouble to commutting at -40, with the electric defrost on all the time. I finally put in a VDC Electronics Battery Minder and it works well at keeping the small battery properly charged and conditioned. http://priuschat.com/index.php?showtopic=27552 Now that I'm frequently away on business, using my Battery Minder is even more important. Over the past two weeks I was away on business, then at my hobby farm on vacation. Tomorrow I'll take the Prius for a quick spin to do errands, and probably won't have to worry about the battery. I also use battery tenders on my new FJ Cruiser, the tractor at my hobby farm, and the old Ford pickup at the hobby farm.
Thank you all for your responses. It seems that the 12V battery is somewhat of a weak sister compared to a "normal" car's 12V battery. I have left a dome light accidentally on, in a non-hybrid vehicle, and had no problems starting it the next day. It seems that the Prius battery is very easy to accidentally discharge and its life expectancy after that is severely reduced. What is the availability of this battery when it has to be replace? Is it only carried by Toyota or do any other retailers, who sell batteries, stock them? I have had the car for 2 months and love it. My primary concern is because of the technology I am locked into the dealer for service. All my other cars have always been serviced by a local mechanic who I trust. When I have had a problem they are 5 minutes away and I can just take the car over to them to look at. Going to the dealer is a little more complex and unfortunately more costly.
Well, the anti-Prius (2001 Pathfinder) battery was still going strong after 7 years of use when I traded it in! And that's in "real winter" country, like jaymans. I'm hoping my Prius battery will last as long (fingers crossed). I -was- very careful to keep it full of fluid, adding distilled water at least once a year. Can't do that with the Prius battery. With the Prius, keeping it fully charged is the only thing we can do to maximize battery life. A "battery tender" is not a bad idea. So far, nobody has found an exact replacement anywhere but from the dealer. It's rather expensive from there as well - in the $250 range. Larger dealers should have one in stock, or available from the Toyota Parts warehouse in a few days. Smaller dealers not so much. One -could- replace it with something like an Optima #51 yellow top. But that would take some work.
It's unlikely that anyone's going to look at this thread anymore, but, for what it's worth, I'm still using the original 12v starter battery that came in my Prius. I took delivery of my Prius in September, 2000; that's right: the battery is a little over 10 years old! And I live in the Boston suburbs, so it's not as if my car has never had to deal with cold-weather starting.
Has anyone looked at the gellcell batteries used for emergency lights and wheel chairs. I used them in my recreation aircraft with very good results. They come in allot of different sizes, so there should be one that fits. Mazda use them in the Miata and come to think about it ,it is about the same size as in the Prius. They cost around $100 , much less than Toyota. H
Gel cell batteries are nice, but if you ever fully drain them and leave them drained for a few weeks you will have to replace them. Like any lead acid battery, they will sulfate in this condition. Unlike other lead acid batteries you can't get the sulfate off the plates, due to the gel. With liquid electrolyte and glass mat cells, it will fall off with aggressive charging. The other problem will be finding one at that price that actually fits. I've looked and the ones that would fit were in the $200-$300 range. And you still have to deal with the terminals being different.
...the available physical space, and has a capacity of ~35 Ah. Easy to find a battery with lower capacity that would fit, but that would be unsafe in the event the DC/DC converter fails.
The 12 volt battery is in the passenger space with you and your loved ones. Toyota's battery has a vent tube to avoid fumes in the cabin, elearnaid's Optima kit has adapters to use the vent tube as well. Any battery you plan should be vented to the outside as well. Prius parts
I do keep a 7ah gel in my car and charge it up periodically while driving on a trip, I use it for a emergency and also not to lose memories when the battery is disconnected. I do not use it as a permanent battery replacement. They cost about $20.00
AGM UB12350 is suitable replacement. It's 35Ah, deep cycle and fits in the base. I haven't heard any try it yet. I trying to procure one for $40.
Here's a really good guide to Lead Acid batteries. http://www.vonwentzel.net/Battery/00.Glossary/ Be sure to read the section on VRLA. Most AGM and Gel batteries I've seen don't have vents holes. Where would the holes be if I need to find them?
