12 volt battery

[maximus2112]

This could be related to the Smart Key System. I was told that if I was
not going to be driving the car for a week or so, to turn off the smart key
system, its a button under the steering column. Don't know if it would
drain the battery like a light, but it is something I'll remember.

[racerbob]

I just purchased a 2008 package 6 in March (12/07 production). The 12v battery went dead AFTER the salesman moved the vehicle to a new parking space before even making it to the wash bay. I insisted that they assign it to a certified tech and put it on the charger and test it afterwards. While watching my ScanGauge aux battery voltage drop (after powering down) while brake pumps, coolant valve, etc. were load testing the battery, I decided it was time to upgrade to an Optima. When performing the swap with only 1k on the clock, I noticed that the positive terminal was green with corrosion on the bottom ring next to the batt post. This is from acid seeping out around the crack where the post and the battery case join. If you haven't checked your battery in a while, it might be a good idea to clean the terminals and install treated felt rings under the terminals to neutralize any acid that will seep out of this joint. I even installed a set on the Optima for good measure. I have been using these felt rings for years on all our fleet vehicles with top post batteries and have not needed to maintain any battery connections that were "protected". The holes are a bit large for the Japan spec battery posts, but they will work well at neutralizing the acid before it corrodes the connection.

[rigormortis]

at roughly 25,000 miles i took my prius to a local toyota dealer and the prius specialist did a load test on the 12v aux battery, and after i whinned a little it, they actually replaced it for me, free of charge, and even gave
me a free detail coupon.

the prius stranded me a couple times after me sitting in the car and listening to the radio for 20 minutes or so in ACC so i had a feeling it was weak and sure enough it had a bad cell


i havent tried turning in the coupon yet

[grambo_811]

All,
I have a 2007 Prius and am now on my second 12 volt battery. I was on vacation for 5 days and returned to find a dead Prius in my garage. I was able to "jump start" it with my electric car but that is another story.
In speaking with the Toyota service advisor they informed me that if I was not going to drive the car for more that two (2) days I should connect it to a 2A trickle charger while I am away. I think that has to be an complete line of BS. I have checked and both times there were no lights left on or anything like that. The first time the dealer replaced the battery the car didn't die. It would just discharge the main battery pack overnight in the garage. The second time the main battery pack was not discharged just the 12 volt system was dead.
Has anyone else had this problem and gotten it resolved?

[andyprius]

Originally Posted by grambo_811

All,
I have a 2007 Prius and am now on my second 12 volt battery. I was on vacation for 5 days and returned to find a dead Prius in my garage. I was able to "jump start" it with my electric car but that is another story.
In speaking with the Toyota service advisor they informed me that if I was not going to drive the car for more that two (2) days I should connect it to a 2A trickle charger while I am away. I think that has to be an complete line of BS. I have checked and both times there were no lights left on or anything like that. The first time the dealer replaced the battery the car didn't die. It would just discharge the main battery pack overnight in the garage. The second time the main battery pack was not discharged just the 12 volt system was dead.
Has anyone else had this problem and gotten it resolved?

The dealer should be able to detect a abnormal current drain, on either the HV or the 12V. Unlikely the 2nd 12V is also bad, but it's possble.

[Tchou]

no light yes, but if alarm was turned on or SKS this may drain the battery while the car is not used...

[bruceha_2000]

Originally Posted by grambo_811

All,
I have a 2007 Prius and am now on my second 12 volt battery. I was on vacation for 5 days and returned to find a dead Prius in my garage. I was able to "jump start" it with my electric car but that is another story.
In speaking with the Toyota service advisor they informed me that if I was not going to drive the car for more that two (2) days I should connect it to a 2A trickle charger while I am away. I think that has to be an complete line of BS. I have checked and both times there were no lights left on or anything like that. The first time the dealer replaced the battery the car didn't die. It would just discharge the main battery pack overnight in the garage. The second time the main battery pack was not discharged just the 12 volt system was dead.
Has anyone else had this problem and gotten it resolved?

Total bull. From day 1, the 'rule of thumb' has been as Daniel said - turn off the SKS if you are going to leave the car for more than 2 weeks. Nothing more. No trickle charge, no 'disconnect the 12V'. You either have a bad 12V or there is something shorted in the electrical system that is draining it. A friend of mine had that problem with a 2007 non hybrid Camry. They tried to tell her it she left a dome light on or something. I said BULL. I've left mine on over night at 0F several times and the little 12V in my Prius didn't die. Certainly doing the same in a car with a 'regular' size 12V wouldn't. They finally spent the time to trace and found a short or something. No problems ever since.

If your traction battery actually drained overnight, you probably hadn't shut the car down. There is no connection between the traction battery and anything else when the car is shut down.

If you put the car in 'accessory mode' it will shut down after about 1/2 hour so you don't accidentally drain the 12V. I've had that happen a couple of times while listening to Car Talk while my daughter was at her swimming lesson. No problem, just turned it back on.

[andyprius]

Originally Posted by grambo_811

All,
I have a 2007 Prius and am now on my second 12 volt battery. I was on vacation for 5 days and returned to find a dead Prius in my garage. I was able to "jump start" it with my electric car but that is another story.
In speaking with the Toyota service advisor they informed me that if I was not going to drive the car for more that two (2) days I should connect it to a 2A trickle charger while I am away. I think that has to be an complete line of BS. I have checked and both times there were no lights left on or anything like that. The first time the dealer replaced the battery the car didn't die. It would just discharge the main battery pack overnight in the garage. The second time the main battery pack was not discharged just the 12 volt system was dead.
Has anyone else had this problem and gotten it resolved?

The Toyota dealer in my area

insinuated the same tihng during my first 3 months of ownership. They ended up replacing the battery to retain my good will. After that I had no more problems. I would have rather that they had checked the battery out and admitted it was deficient. I asked them for the battery so I could play with it ( test, disassemble) They said NO they have to send it back to Toyota so they could study it. In actuality I think it has high scrap value ( to Toyota ) I'm still awaiting the study results.

[ChuckC]

We bought a Prius six weeks ago. Monday, July 21, 2008, the car died on my wife and we had to have it towed to the dealer. We were told the computer said we were out of gas. We know that to be not true. They jumped the 12 volt system and told us everything was OK. Tonight ,Thursday, July 24, as I pulled into my driveway the check engine light came on along with several other lights. After several calls to the dealer. we were told they did have a loaner and they could check the car out tomorrow. Is this going to go on and on?
Tune in tomorrow for results of their review of the smartest car in the world!

[Patrick Wong]

Prius does take note of, and store a warning when the vehicle is out of gas. On July 21 when the car died, how many bars appeared on the fuel gauge?

How many bars appear on the fuel gauge as of Thursday night?

Please ask your dealer to record any DTC (diagnostic trouble codes) that your car logged and to document them on your repair invoice. Then we can comment on what might be wrong with your vehicle. Thanks!