Well it happened.

Peter Granzeau:

Sounds like a wise choice. The Prius isn't suitable for everyone.

I had the 12-volt battery in my '06 Prius go dead in the morning on Christmas Eve. Fortunately, I was not far from home and my wife arrived shortly with jumper cables. I drove straight to the Toyota garage and they did some diagnostics, recommending only that I recharge the battery and then have them test it again. I can't afford to be stranded in the winter, so if there's any question of battery condition I will replace the battery. Four years / 32,000 miles isn't a very good lifetime for an automobile battery, methinks.

Davoud

Mine lasted about six years and 69,000 miles. And it appears that Toyota is the only place to get one. Pep Boys and Sears do not carry the 12-volt battery for the Prius, but I didn't check any other 3rd party source.

Huh.

I've drained my 07 12v battery once (within the last year); jumped it, left the car in "ready" for 20 minutes or so, and went on my way.

Did you try disconnecting the 12v battery to reset the system? Low system voltage plays hell on cars. I know of a 2001 Ram 1500 pickup that when the battery terminals need to be cleaned it will start and run but will not idle, you have to keep your foot on the accelerator to keep it running.

I know on the NHW20 gaining access to the dead 12v battery is no fun since the hatch only opens electrically but it would have been worth a try.

From the wording of your post however it sounds as though you already have your mind made up about this which makes me think only 1 thing: what color is it and does it have SKS? I am looking for an '06 Seaside Pearl with SKS.

I don't like Fords because of the Mike Rowe BS in the commercials and past experiences with them (I do my own maintenance), I don't like new GMs because of the EV-1 thing, I don't like newer Chryslers made since the Daimler merger, the NHW11 is too small, the ZVW30 has that ridiculous suspended arch joining the dash and center console, hence I want an NHW20 Prius. My current car is a '97 Lumina

Just about any 12V battery will work in a Prius since it doesn't crank the engine. 2 popular options are a Mazda Miata battery, and an Optima yellow top. I would probably run a group U1 AGM power wheelchair battery if I had a Prius. I wonder if a 22nf wheelchair battery could be shoehorned in?

Keep in mind that the posts on the OE battery are smaller than standard SAE top posts so you would have to either trim down the posts on a replacement battery or change the ends on the car. The easiest is to get a battery with studs or flag terminals and just remove the clamps from the car's ends and bolt them on.

Daniel who wants to know:

Bzzzzzzt! Wrong answer. The *easiest* way to deal with a dead Prius battery is to go to the Toyota dealer and have them install a new battery. The impecunious are often forced to do things the hard way, while the skinflint often chooses to do things the hard way. The rest of us understand that time is the world's most valuable commodity.

Davoud

Nah, the easiest way is to trade it in on a new Prius. But that's probably the most expensive way. ;)

I had a Corolla with automatic transmission. One morning I had a flat battery and couldn't shift out of Park. The man from AAA gave me a battery boost and said the transmission would not work with a flat battery.

Probably because of a shifter brake interlock system using a 12v solenoid. My Lumina has one of these too, an audible click/clunk is heard from the steering column when applying or releasing the brake pedal while in park. These can be somewhat easily defeated with a dead 12V. The NHW20 Prius has a gear reduction switched reluctance motor on the transaxle to actuate the parking pawl and IIRC it has to be removed to manually take the car out of park. The NHW11 however had a "normal" cable operated parking pawl linked to the shift lever inside.

Sure it will. You just need to read the owner's manual.

Absent electrical power, you need to insert a flat object into a slot near the shifter in order to release the shift lock.

Voila.

This is the part that has me confused. Testing the cabin light auto- turn off, I ran our 12 V battery down in our ZVW30 (2010 Prius) and got to use the engine compartment, fuse box tap. I understand your NHW20 has a similar setup. But I found it took more than bringing the voltage up to over at least 13 V on the charger before the car would start.

My first attempt to start failed with error lights that faded as I tried to start the car. I suspect the electronic power brakes put an early, heavy load the barely charged battery could not handle. So I put the charger back on. After an additional charge, I was able to start the car although some error lights remained on. I let it run for five minutes and then turned it off to clear the error lights and the car started right up.

You may want to check your next car to see if it has an electronic controlled transmission. Electronic parking paws are likely to be more common than with just hybrids. I don't believe it is a problem with manual transmission cars but I'm not an expert.

Bob Wilson

The original battery in our 2003 Prius began failing in the winter of

Bob Wilson

One caution about trying to trim down the battery posts. I was surprised to find that many of them are hollow.

Bob Wilson

On Sun, 2 Jan 2011 14:10:11 -0800 (PST), bwilson4web put together some random words that came up with:

It's not worth fooling around trying to find a substitute battery. Call around to the various Toyota dealers and you will find a wide variety of prices for the

I have an '04 Prius and replaced the 12 battery after 4 1/2 years. The battery seemed ok, but since the life of these is about 5 years, I figured better to be safe than sorry.

As far as the comatose car. If your car is under warranty, by all means get it to the dealer. However, there is an easier thing to do. Get a Scangage II. I have a ScanGage II that I use while driving that displays general gages, but when I had my Prius go comatose on me one time, I used the ScanGage to read the trouble code (it was some weird communication lost code. I cleared the code with the ScanGage, and have never had the problem since. Probably just a computer glitch. I suppose a weak battery might have caused something similar. It seems with the Prius, if there is something like a Check Engine code, the car will stay locked up until the code is cleared. Unless you have a friend in the business, the ScanGage is the cheapest thing to do this with.

I have no connection with the folks who make the ScanGage. Just a happy customer.

Steve

I'm not up to doing anything under the hood any longer, and disconnecting the 12V battery would be worse, as that would be someplace under the hatch, right? Anyway, if this had been my home computer, I would have disconnected power right off. Prius needs a "final power" switch someplace to remove power from everything.

But the inability to get the car out of Park with a dead battery also needs attention.

The 12V was weak, but not quite yet dead (the clock was still working, for instance). And those AAA trucks have a pretty good power source, as everything turned on real bright when he connected. Unfortunately, I still couldn't get the car out of Park.

My '05 is fast approaching 100K miles, and I have had zero battery problems.

Sounds like your 12v battery died for some reason (lights left on, aging battery, etc.) and left your Prius without sufficient 12v power to start. The long term fix is to replace the 12v battery. It's a relatively small inexpensive battery...in the $50 range at CarQuest. The short term fix (so you won't have to call a tow truck again) is to jumpstart the vehicle. Under the hood, there's a + battery post that connects directly to the 12v battery buried out in the back. To jump start the Prius, you pull another vehicle next to your Prius and place a battery jump cable (the red one) between the + post on that vehicle and the + battery post under your Prius hood. Nothing will happen, though, until you also connect the negative battery post on the jumpstarting vehicle with the frame on the Prius. This is what you do next. It is very important to get a good connection to some part of the Prius frame under the hood...not some piece of black plastic. The Prius only has one cable back to the battery (the + cable) so the frame serves as the negative cable...but only if you make a good electrical connection. Once you have the + and - terminals properly connected with a good voltage source, when you push the Prius start button, the main relay will pull in and drop the powerful main Prius battery online and you will be up and running. Too bad about your experience but you live and learn. If you sell your Prius, though, you'll still be okay as the resale value on them is very strong because of their performance and reliability. Good luck!

It's an '06, 21000 miles, and the local Ford dealer offers $10,500 for it in trade for a Fusion. I don't know how that works, but his black book ranges below that amount.

In my incident, the battery was in fact low, but the first thing tried was a jump. The car wouldn't come to Ready status (e.g., no change in the car). Only after the car wouldn't turn on (it was stuck halfway on, with every ready light on the dashboard lit), we decided to tow it.

When the holiday weekend was finally over, I called the service department, and they said the car started right up when it was delivered. Maybe the bouncing and jouncing it got being taken to the dealer got it to reset.