12 Volt Battery

There is a TSB EL014-03 that could get you a free new one, if you were under 36 months in service:

http://autos.groups.yahoo.com/group/toyota...Bs/EL014-03.pdf

(you have to join the toyota-prius-sat1 group to view that, but it is painless)

There is a Miata battery that can be modified to fit:

http://home.comcast.net/~dldorrance/battery.html

and an aftermarketeer selling the pieces:

http://www.elearnaid.com/priusparts.html

If you are one who is willing to forgo whatever protection the battery vent tube actually provides, there are many options in terms of sealed lead acid batteries. I would not want one smaller than 28 amp-hours (as the original). If you go that route, please connect it with something more substantial than little slide-on connectors.

 

I got a similar problem on a Prius 2002, but my auxiliary battery is only 6 months old. If I leave it for three days, it drains: when switching on the car, the lights in the front panel would come up unusually dim and the car won't start without a jump.

It all started doing this about 3 weeks ago. Before I could leave it parked for a week without any problem.

I took the car to Toyota and they checked the electric system. They said that the electric system was OK and that probably the problem is that the auxiliary battery needs to be changed with a "genuine" one rather than an aftermarket one. I had indeed bought the battery from an aftermarket (but the battery is specifically for Prius and it came brand new). Since the battery is under warranty, I tried to ask for a replacement. However, the aftermarket seller told me that if the battery is taking three days to drain, then it must be something in the electric circuit that is draining it. If it was a problem of the battery, it would drain in a matter of hours rather than days.

So I'm in a crux here. Toyota would like to sell me a new "genuine" battery, while the aftermarket reseller is washing his hands.

I don't know who to believe. And the worst is that I did not get Toyota to categorically tell me that the battery _must_ be changed. In fact, they even wrote "load test OK" in the invoice which I assume means that they did a load test on the battery and they found nothing really wrong.


Thanks

 

I had a situation just like yours. I bought what's called a battery tender. It is simple to hook up and use. All it does is automatically keep your battery at just above 12 volts or so. Every night you connect a small plug from the charger into the other end which is connected to both terminals on your 12 volt battery. It's all automatic. The tender plugs into any AC outlet and has a red and green light to show you the battery's status at all times. I have 2 tenders and they work great. I paid $40 for each one and have not had any trouble starting either vehicle since then. I also was told by dealers that nothing was wrong with my charging system. I doubt very much your after market battery is a "dog." That's the best advise I can give you.

 

Hi Mdumas, welcome to PC and sorry that your first post was about a problem.

Where are you, maybe somebody nearby could take a peek?

When your Prius is switched off, its "parasitic drain" should be about 40 milliamps or less. It would take a digital multimeter and a little skill to check it. Hint: remove the trunk light bulb 'cause it will be on. If the drain is much larger, the Prius is at fault and needs service. If you do not have "daytime running" headlights, but you leave the light switch on, the lights will extinguish, but a small excess current drain remains.

If the drain is not too high, then maybe you have not run your car for long enough to fully recharge the battery? A fully charged 12 volt PbA should show at least 12.75 v with all loads removed.

If your replacement battery is in fact a dud and the seller won't help you, this is a problem. But I feel quite confident saying that Toyota's 28 amp hour battery is no better that anybody else's of the same capacity. I switched to the MK (aftermarket) battery last February and it is still fine for me.

 

I don't think the 28AH Prius Battery is as good as anybody elses. I'm not sure that Toyota accounted for a car sitiing idle for a week, in colder climates or of the normal parasitic drains in the car design.

 

Hi:

I am just joining this chat because I too have a 2002 Prius with about 16,000 miles and it has developed 12V battery problems. Several months ago the car would not start and someone recommended that I get a "trickle charger" that plugs into ordinary wall current and that seemed to fix the problem.

Then, two nights ago after driving fine (and filling the tank with gas during the trip), when I started it up again I got all three indicator lights on page 98 of the owner's manual ("PS"; battery picture with the word "main" under it ;and red and white car outline with an exclamation point in the middle) that scared the dickens out of me.

I was way out in the country so I drove it home (about 15 miles-largely down hill) . The service rep at the dealer told me on the phone that meant it had been running solely on the big battery and that the gasoline engine was not working (there as also an amber picture of the engine lit up on the dash) However, they couldn't get to it for awhile even if I drove it in or had it towed in.He suggested that I try using the trickle charger if I had one.

So I put the trickle charger on last night for about 16 hours and the car works fine again, no warning lights, no problems.

Any ideas about (1) what I should do, if anything, about 12V battery and (2) should I take it in to dealer for some kind of check after driving around with all those "take to your dealer as soon as possible" lights having been on?

I'd welcome anybody's ideas on this . Thanks

Raven