Recharging after Dead 12v Battery

You need to remove the battery and have it checked. If it is under warranty take it back to your nearest Toyota Dealer. Charging a bad battery with an internal short IS like hooking it up wrong. Ginnyerns may have done just that in her situation as she seems sure (and I do not doubt her) that she made the correct hookups. I sincerely hope Ginnyerns does not have to become Ginnypaysbigtime. Good luck to you. Get that battery out and have it checked for an internal short!!!!

When you remove the battery, you are removing it from the rest of the electrical system. When you hook up the charger you should watch the charge meter closely as it should take a reasonable amperage to start and then slowly go down. If it does not then stop charging and have it checked.

The jumper terminal under the hood is for jumping only and not for hooking up a long term charger! It is made for a 14.2 volt max normal 12 volt car battery to be hooked up to for a jump start, or a dedicated jumper unit. The donor car should be at idle. Consult a Toyota Dealer about hooking up a battery tender and get it in writing that it is safe to do and will not void any warranties!

My friends Prius recently would not start after sitting for a few hours with the radio playing while their son was in the car waiting. We think the computer got hosed as when the source battery was hooked up it immeadiatly came to life and started on its own. Low voltage did something to the computer to whack it out. It has been fine ever since ..... but I will warn him about this and other 2007 battery threads.

 

Any luck with the legal angle or the media angle?

 

JAYMAN...Ginny here...to soon to tell on public pressure....but from what I am reading and learning....the more I know....the more I feel Toyota should take responsibility. Did here tonight from Consumer Affairs. They will post my story in a couple of days. Can't remember what I said in the report, but it was before I came on PriusTalk.....wish I had known then what I have learned the last couple of days. Thank you all for the info.

SPEEDYWING....wow I learned more again from your post here. So you are saying that the post in our Prius is set up to take the 14v from our regular car and converts down to the 12v.....wow....I was under the impression from posts on my thread that that could have been my error....that I used a regular car at 14v to charge my Prius......wow so I didn't do anything wrong.......

So.,..see Slearner.,...best not to touch your car.....I wouldn't even try to remove it....cause if you do anything wrong they will void your warranty.....just have it towed in which is covered under your warranty....and let Toyota fix the whole thing...you definately have a problem....so better get it diagnosed and fixed all by Toyota. Also from my readings....sounds like if you work on the car there are some electrical things you need to turn off if the car is worked on for more than a half an hour....Did you get a chance to run thru some posts on my thread....iut is under Tech Discussion #48575

I would appreciate knowing how you come out of this.....thanks Ginny
I really think we need to band together and see if this battery set up can get a new design with more protection.....

 

Im not sure I understand the chain of events, with both Slerner and Ginny. The Negative terminal is easy. it's connected to Chassis ground, the donor wires also have to have correct Polarity. If connected wrong, there should have been a heat (short) mark on one or both terminals. Possible sparks and as one writer said a battery can blow up. Usually this caused by not monitoring, if you are charging at a bench. This also could take many minutes, boiling , odor and heat are good signs of the necessity of quick disconnect. This only occurs at a high charging rate. If you are bench charging make sure the vent is open. On a standard battery take the covers off the cells(maintenance type battery) Use a multi-meter and monitor the voltage. I carry one in my trunk all the time. Any thing will work, analog or digital. They are cheap. When both voltages reach equalibrium, charging will automatically stop. Unless your using a higher current capability or a 24Volt charger. Back to subject: You have borrowed voltage from somebodyelses car, your Prius starts and is running, To Slerner: There is a display that will show the SOC on the accessory battery, look at display, keep it in that mode, make sure that the car is charging at 14VDC at minimum. Either drive around for 10-15 min or put the car in Drive, step on brake, set Emergency brake and gently step on the accelerator. Later floor it if you want, the engine will only rev sufficiently to charge the HV battery which in turn charges the Acc Bat.
Then after driving home monitor the SOC again and make sure you have not forgotten a door, trunk lid or what ever. There are minute parasitic current draws which are normal on the Prius ( and all cars ) this is why it's recommended to eliminate the SKS if you'll be gone for two weeks or more. As I mentioned before I had acc bat problems after three months and had the dealership give me a new battery, got a lender car and left the car there overnight. I deliberately left as many things running on the car as I could, AC, Lights, etc. This was so the Technician could duplicate the malfunction, ie: BAD BATTERY.

 

It is now impossible to prove who did what when. I think you're SOL. Try replacing the fuses and the 12V battery first, and if you're lucky that will be all that it needs. If not, get an estimate from another dealer. $5K is kinda high.

 

FYI: For everyone: My scan gauge tells me that my "12volt" battery voltage is straight up 14.0 while driving with a fully charged battery and the lights, radio and heater on.

Icarus

 

Well, I see it has been a number of months with no new posting on this. I wonder what happened.

As for us, my wife went to get in our Prius Saturday and the door would not open. Since we have the smart key, she thought the battery on the smart key might have died. She called me on the phone and told me what was happening. I explained how to take the emergency key out and use it to open the door. Once in, she plugged the smart key in to the dash and tried to start the car. It was DEAD.

After reading all these posts, I was leery. I called the dealership and they told me it was not under warranty because we have 41,000 on car and battery only covered to 36,000.

Checked the post in engine compartment with a VOM and had no voltage. You can not get to the battery unless the car has voltage. Toyota has no other way to open the rear hatch where the 12 v battery is located, according to the dealership I called for help. They apologized for the "poor design". They told me I would just have to have it towed. Of course the only way to do that is lift the front end of the car. There is one catch. The front end of the car has to be where a wrecker can get to it. Mine was sitting in the drive way pulled up to the garage door. How about putting it on flat bed, he said? I reminded him there is no way to get the car out of park without voltage so you would have to drag it up the ramp of the flatbed. That should be really great for the tires and I am sure the transmission would love all the pressure that would put on it.

Finally the dealer agreed you have to jump the car in order to do anything to it. I connected my daughter's car to the Prius and the Prius started right up. I disconnected the cables from my daughter's car and the Prius ran just fine. I checked the voltage again and it was 14.5, just as it should be with the alternator properly working. By the way, I found the reason the battery was run down. My wife had left her overhead light turned on when she got out of the car. Another stupid design. Most newer vehicles have an automatic shutoff for lights like that one which shuts it off after 10 minutes if the car is no longer running.

I decided to drive it to my brother's automotive shop and have it checked out. The battery had recharged after that 20 mile trip. He put a load tester on the battery. It showed the 12 + volts, but it also showed the battery life to be nearly 0 and the tester showed the battery should be replaced. He called Toyota and got the new battery and installed it. Can you believe the only batteries Toyota has for the Prius is a 24 month/24,000 mile battery.

Bottom line, I don't know if running the battery completely dead ruined it or if it was already in extremely worn shape. Had I not had him test the battery, I would have thought it had just run down and driving it had recharged it. Without the testing, my wife would probably have been stranded somewhere other than home in the next few weeks or so when the battery finally died.

I would suggest everyone have their battery load tested from time to time as the age or mileage gets higher. That way you can get it replaced before you get stranded.

We love our Prius, but Toyota sure has room of improvement in a number of areas.

Ron

 

i'm still on my original battery. if i don't drive it every day, it dies. i have friends with jump packs, jumper cables, and a battery charger on hand. 10a charge is enough to jump a prius

i've disconnected every doors light to reduce energy drain while i turn the car on. my problem is that i'm too lazy to put my amp on a switched +

if your battery dies, charge it. If you don't want to pull it out, just disconnect the - terminal...

 

Hi Ron,

Thanks for sharing your story. Yes, it made perfect sense to replace the battery.

Note that it is possible (although difficult) to open the hatch without 12V power available. You must open a rear door, lower the seat back, crawl into the hatch, remove the folding hatch floor, find a little rectangular panel in the black tray facing the rear of the car and remove it, then find the mechanical hatch release and move that lever to open the hatch.

 

Your wife can train herself to always lock the car when leaving it, no matter where it is parked. If she left a light on or a door open it will beep at her, and so avoid battery drainage.

 

The hatch release is required by law. It's a good idea for all to learn how to access the release. It's possible they could be trapped in the car with the only way out through the hatch. While the release doesn't fully conform with the "trunk release law", it does give you manual control.

The interior lights can be switched to be door controlled or on all the time, or off. It's not "faulty design". Some people want to sit in a car that is off and do whatever with the light on.

The fact that the battery is in the hatch and difficult to access is also not "faulty design". It's perfectly ok to charge or jump the battery from the underhood jump point. In fact, it instructs owners to do so in the owners manual. I recommend the "doner car" NOT have the engine running. I also recommend you double check the polarity of the cables. Start with the positive only. Connect the cable to the positive on the doner car first, then connect the other end of the positive cable to the Prius positive jumper terminal. Next, connect the negative to the doner car. Finally, connect the negative cable to the bolt on the firewall above the fuse box. Start the Prius. Remove the negative cable from the Prius. Remove the negative cable from the doner car. Remove the positive cable from the Prius. Remove the positive cable from the doner car.

Note that a dead battery takes a while to charge fully. Several hours will be required at least. You can leave the Prius in "ready" and lock the doors (with the key). The engine will only run when the traction battery gets lower than the system wants it.

Note also that the "alternator" (MG1) actually charges the traction battery. There is a "12V battery charger" built into the inverter of the Prius that supplies charge current to the 12V battery/system. Technically it runs off the traction battery/motor generator.

 

I left my 2006 Prius doors locked and had to leave it sitting for several months; now the battery is dead and I can't get the door unlocked, even with the small emergency key. HELP!

 

The battery is toast and I recommend u do not jump start it because it will be quite a inrush of current and may damage the car.

If your at home buy a car battery charger at a auto parts store. Open the front hood and take the black plastic cover off the fuse box on the right.
There's a red plastic cover flip that to the right that exposes the 12 volt positive jump lug. You attach the charger to that lug. The red lead of the charger clamps to the little vertical tab of metal there. That's the positive.
The black handle of the charger the ground goes to any chassis bolt I use the nut right above that fuse box
Charge the battery in 2 amp mode for a while which is slowly then after about an hour of that go to 10 amp mode
You know your getting somewhere when u can turn on the headlights.
This is the safest method.
The most dangerous method is to use a car and jumpstart it.

No matter what happens that 12 volt battery is done must be replaced.

Btw your in the wrong forum. You should be in the Maintence and troubleshooting forum. This is the technical discussion forum. Not a lot of eyes will see u here.

But good luck and if in doubt come back and ask. Be careful here as hundreds of people have damaged there Prius in this situation.
Use the search forum button at the top and search:

Dead 12 volt battery

 

That and u resurrected a 9 year old thread lol.....

 

I see now you can't get the door open. Buy some spray lubricant that has the injection straw and spray the hell out of the lock
With wd40
Shove the straw inand spray spray lube on the key too and insert.
After the lube gently turn the key to the right that's unlock.
Rock key back and forth but to the right opens the door.

 

The emergency key should work. Sorry I'm not that up on US geography, is CO Colorado? Could be lock is frozen? If so, maybe run extension cord and warm the lock with hair dryer? Or carefully heat the key with a lighter, just the tip, you don't want to melt its plastic. And handle with gloves.

I believe it's clockwise to unlock? Try gently both directions. And if you've got two fobs try the second emergency key.

That's all I got, lol. Hope it works out.