2010 II 12 Volt Battery Dead After 17 Days of Parking

I think you can do it with a couple of lantern batteries, especially if you pull the brake booster pump fuse and unhook the 12V battery first, then put them back as soon as the car starts.

I made a little kit, two lantern batteries, jumper wires with alligator clips, and a note telling me which fuse to pull. Hint, if you buy lantern batteries lift them and buy the heaviest ones you can find, they have more capacity.

I haven't tried starting the car with my "kit" yet but I think it may even work without pulling the fuse or unhooking the 12V battery.

 

I will be leaving my car in a parking lot for 15 days. I was wondering (after reading all these post on dead battery) if you could turn the clock off and the anti-theft light on the dash off this would help stop the drain on the battery making it last longer. I looked in the owners manual found no help with this issue. My friend has a gen II and he has turn everthing off and walk away for 2 months with no problem, he must use a key to help start the car may.

thanks all for the help with this issue. I forgot to mention that I have a gen III package 3

 

Let me start by saying I'm NOT a mechanic! I bought a Prius II on December 31st 09. I was so scared of the possible future problems I bought Platinum++ Service for 2 years longer than my payments.

Two days ago I drove the Prius with a GPS plugged into the cigarette lighter all day. The next day my wife drove it to work 15 miles away and back. On the second day the car would not start and had an error message that said the park function had failed; It said to park on level ground (ya Right) and apply the manual brake.

I decided since the entire system is electronically controlled and after months of my wife babying the car driving with the head lights on for 15 miles to and from work and always parking without applying the manual parking brake the batteries had been severely discharged and had never been fully recharged. One more night without the parking brake applied was the last straw.

I remembered the instructions for parking state to use the manual parking brake. I thought maybe the Parking system is electronic and continually uses the battery to hold the car in park unless the manual brake is engaged which is why it was discharged after nothing unusual except parking without the brake.

I checked out the owners manual and found the battery terminal under the black plastic cover on the drivers side in the corner of the fender and windshield under the red plastic positive post cover. I attached a trickle charger to it and grounded through the paint on the fender frame and let it charge all day at 10 amps. When it showed it needed 2% to be fully charged I started thinking the batteries may be getting hot so I stopped.

Today the car drove fine.

So Mr Wizard... what do you think? Did I figure the problem correctly or am I in for some other problem I have not thought of?

 

My girlfriend and I took a 7 day cruise and drove to the port in her 6 month old Prius. Got back and the battery was dead. The parking lot loaned me cables to jump it off and had no more problems on the trip. She took it to the dealership that she purchased it from on returning to home. They told her that was normal for her car, even though the owners manual plainly says 30 days before the battery should run down. Said was no way to bypass anything. She would not have bought the POS if that knowledge had been conveyed previous to her purchase. I have had experience with Honda Hybrids and they do not have such a fallacy. Since she's stuck with it, we will try a solar charger next trip. Just glad we didn't get back to port at 2am.

 

The parking brake has nothing to do with the problem. When you power down the Prius, the HV battery is disconnected and the "Parking Pawl" holds the car still. Any drain on the little 12v battery will run it down quickly (door ajar, accessory lights, ...)

A 10 amp charging rate will cook the little 12v battery quickly (it is rated at a 2 amp charging rate max). You may need a new one now.

You can check the status of your little 12v battery using the MutiFunctional Display (MFD) see:
http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html
Good luck.
JeffD

 

I came home after a 10 day vacation and found my Gen III would not start, just as described here and in other 12v battery threads. Luckily, I did not drive the Prius to the airport so I found it in my garage dead. I am posting here and will in another older thread to identify a couple of things that I discovered that were previously unknowns.

When you disconnect the 12v battery (to charge or replace), you do not lose the ECU dealer programmable settings such as seat belt and reverse beeper settings. My settings are just as they were prior to disconnecting. Driver and passenger seatbelt warning beeper disabled and reverse (backup) warning beeper set to one beep. Those settings did not change and my battery was disconnected for 3 days. The things that changed back to default or things that I lost were the radio station presets and the NAV system programming was lost as if it did not have the NAV data disc installed. All that was necessary was to allow the NAV to reboot and recognize the disc...however, it defaults back to the region it was factory set to, not necessarily your home region. The NAV does know where it is and displays the car on the map in the correct location, you just can't look up addresses as they system in my case reverts to the NE region instead of the south. So when you look for a city or street, it will be in that region. So you must change the region as well after a 12v disconnect.

The service manager at my dealer (Jim McNatt-Denton, Tx), tells me that they have had a number of 12v drain issues on the Prius that sat over 10 days. He tells me that most of them had no issues once the battery was charged again. He did say that they have found a number of batteries that had an internal issue and would not hold a full charge. This is the issue I believe I may have. After the vacation discharge, I charged my battery back up with a Pulsetech XC100-P Xtreme Charge. It will desulfate a battery and bring back a dead battery very easily. However, after charging and driving the car only 30 miles, after a four hour period, the battery was discharged and the car would not start again. I once again put the charger on it and when it was back to 100%, I tried to start the car with NO success. I was however able to jump the car from my truck battery and took it into the dealership today. Based on what I know and have observed, I believe I have a bad battery. These are AGM (absorbed glass mat) batteries and do not become as sulfated as a typical flooded battery, however, they can still be degraded due to sulfication to a degree. As for how a new battery develops a bad cell??? I don't know, but suspect that any degree of sulfation causes the current charge to build up going from one cell to another and stops against a plate that is sulfating between plates and either over or undercharges that plate...and it dies. My charger is capable or reversing this to a point. But it may just be a bad battery from the start. I run dual AGM's in my boat and would not give you a nickle for the optima batteries, I have another brand without near the return or trouble issues. But I have a great deal of experience with the AGM's and I also run a battery switch and ACR (automatic charger relay) setup in the boat. So I understand their characteristics and think my Prius has a bad battery, although I only tested volts and did not look at the amps.

I would also like to add that a battery under load will act differently than a battery that is static. You may show 12.6v and good amps on a static battery and put a demand on it and see a big drop. A good battery will hold up under load.

Sorry to run on and hope the info is helpful.

 

I wanted to update...it was a bad battery. Now, how did the battery get that way? No telling and as you said, the service tech does not have the time or inclination to keep the car the 3 to 5 days to allow all the ECU's time to attempt to power down and find the culprit. But some of that drain takes its toll on the battery over time so now mine was a dead soldier. The service manager told me it is a 325 cranking amp battery and it was putting out only 77 cranking amps at a full charge. That is the load I was referring to earlier. The battery will look good until they can load it up in test as if you were cranking and measure the output amps at that point.

I also want to clarify a few things about AGM batteries. Because of the glass mat that is between the plates, they are very stable and capable of taking much higher charges. They can also hold more of their available amps longer even though the ratings on them may indicate they are not much better than a standard flooded lead acid. An AGM battery IS a deep cycle battery and depleating it and recharging should not affect the life of the battery at all depending on how it is charged back and if it is never overheated. But unlike a flooded standard lead acid battery, you can leave an AGM in a discharged state without affecting the health of the battery once it is recharged again. My portable charger won't hurt it as a matter of fact, when it gets to the maintenance or float (other chargers use these terms), it is actually using two different current styles and that pulse actually will desulficate a battery (all batteries get this to some degree, some worse than others).

Having been a member here for a number of years, I have seen this as a good site in many ways...members helping members. But as PC has grown, I have not been active on any basis except when I needed info. I am glad to be able to contribute something because you guys have helped me a tremendous amount. Now, if they would just come out with a lockpick for the 2010 to do the things I want, then you guys could tell me how to install it! Thanks for all of your contributions!

 

It's happened to us and the hatch would not open. Under the fuse cover in the engine compartment is a red plastic cover maybe an inch long. Open it and you will find a positive terminal. Nearly any 12 volt source will raise the voltage enough to start in less than 5 minutes. (the negative terminal is the engine.) Toyota needs to fix this!

 

I have a similar problem with my 2010 Prius except it only sat overnight in my garage and no, I don't think I left any lights or anything on. My battery was completely dead in the morning. All screens black. I got a jump from my neighbor and it started right away but I did not think to sit and let it charge (having no understanding of the two-battery system until now). Drove it to work, about 20 minutes. As soon as I turned it off, everything was black again. Dead. Got a jump and drove it home. Now it's in the garage, and dead again. Tomorrow I will take it to the dealer. What could be wrong? And another related question. When it goes all the way dead like this, if I had to move it, say just to push it out of the garage, how do I get it out of gear and into neutral. Anyone know? There must be a way...

 

As far as I know their is no way to get it in neutral without having it in the Ready mode. If it had to be moved without power the front wheels would have to be lifted off the ground, or dragged.

As far as your car, getting it fixed by the dealer is about your only option. It probably has: 1. a shorted battery that simply won't hold a charge, 2. a non functional charging system, or 3. something in the 12V system that is staying on and draining all the power out of the battery. I could also be something obscure such as the fused link in the battery cable. Fortunately it seems to be a "hard failure" and that is usually a lot easier to find than an intermittent failure.

Be sure to let us know what the dealer says the problem is.

 

No problems leaving for 11 days

I left my 2010 prius 2 out of the sun but in 100 + degree heat for 11 days in AZ with no special prep and it started and ran normally with no change in the level of the traction battery. YMMV.

 

This is factual. I left my Prius (2010 trim II) in my garage for full 47 days (9/30 - 11/15/2011) for an overseas trip. All battery connections intact, just locked the vehicle and left. After coming back, no problem at all, started right away at the push of power button.
May be leaving the car indoor vs outdoor will make a big difference in retaining battery charge? ...Mine is the same trim II as the original poster.

 

I had my 2010 Prius' 12v battery replaced free of charge from the dealer about 3 weeks ago after I told them repeatedly that the car wouldn't start right away whenever the temperature dipped below freezing. What happened was whenever I tried to turn on the car the dashboard lights lit up but the ready sign wouldn't come on. I couldn't turn the car off either. I had to press the Start button several times before either the ready sign came on or the car was turned off. Since this winter's been quite mild I couldn't repeat this scenario at the dealership. They finally tested the 12 v battery and found it low. How low they didn't tell me but they agreed to replace the battery free of charge. From then on I can start the car at any temperature. By the way, it ran well the winter of 2010-2011.

 

I just had mine replaced - 2010 w/11,000 miles. It first went dead after sitting 15 days while away on a trip. The second time was after 5 days. The dealer checked the battery and found a dead cell - seems common for these cars. Battery replaced under warranty.

 

So, this means battery covered for 3 years/36,000 miles, right?