Re: 2007 Camry Hrybrid battery draining?
 

If "chaos and mayhem erupt", how would you ever change it when it's time to replace that 12 volt unit? If you want to be safe and not lose any programing, make sure everything posible is turned off on the car, remove the trunk light bulb, add a jumper from the battery negative post to the ground wire (10 gauge wire or so as very little current will be used by the car with everything off) and then disconnect the battery cable.

Use a low amp probe around that wire to figure out how much of a draw the system has. You can also use a simple test light to check as well. At that point, you start checking individual circuits to see what is causing the drain. I have seen BCM controllers keeping the stereo amp turned on, glove box/trunk light circuits and similar problems but with yours draining the traction battery down that fast, it should be fairly easy to find.

Re: 2007 Camry Hrybrid battery draining?
 

I think haroldo had the best suggestion back in time.:lightbulb

Run two jumper cables for 12V backup to avoid any mayhem later.

Two points of connection are easy to use:

1. negative cable is, actually, simply bolted to the floor, and that's point 1
2. positive has metal plate, connecting 2 cables together, somewhere half way cable length. Has 10mm head bolt, I believe, and that your point #2.

Simply attach 2 jumper cables there, then hook it up to a backup battery. Any $20 worth battery should do it, as entire job, with thermistor switch, is about 15 minutes. Personally, I am connecting bypass cables with engine turned on, as then traction battery is feeding power to the systems.

But, even if it goes sour, and warning lights come up thereafter, cycling power on and off 3 times normally clears them.

Unfortunately, I came across at least one guy, who did straight swap, battery disconnected, and his ECU chose not to like it. He ended paying over $500 to a dealer to clear a bunch of error codes.

Re: 2007 Camry Hrybrid battery draining?
 

It's no problem at all.

Not sure if I follow the approach though. 12V is supposed to have some draw all the time, as it's back up battery for systems that run idle, whilst car is turned off. Traction battery is charging 12V battery, but as equivalent of alternator. I am not sure, how you can track down traction battery drain by checking on 12V drain - as it should be there basically all the time.

Re: 2007 Camry Hrybrid battery draining?
 

The 12 volt system always has a draw as you noted but it is not that large. For the traction battery to drop that much, you either have a short in the traction battery pack or a large parasitic draw on the 12 volt battery which is recharged from the traction battery. A parasitic draw that large will be easy to spot as it will not be measured in milliamps like a normal at rest draw would be (key system, arlarms, etc).

Re: 2007 Camry Hrybrid battery draining?
 

Got it. It all centers on - is traction battery recharging 12V one, when car is turned off? I doubt it is. If it does, there's no point in having 12V battery, it's redundant then. Makes sense? Why charge from traction, if you can feed from traction? Small transformer or something, and here ya go.

Re: 2007 Camry Hrybrid battery draining?
 

I think you are correct, and the 245 volt traction battery is not connected when the car is "off". If it was connected we would not have the issue of the 12V discharging when the car is off. The prime purpose of the 12V besides being a buffer to power the delayed off headlights, etc, is to provide control power when the car is off. See figure 2.2 on page 2-3 of the report below. It shows the basic electrical wiring diagram. There is a relay on both the positive and negative terminals of the traction battery. Suspect those relay contacts are open when the car is off.

Technology Report

If true about the only way you should lose power in the traction battery when the car is off, is due to internal shorts. I recall reading that some loss is normal. The question would be how much. I am not in the habit of recording the bars when I turn it off, and then compare it to what I have when I start it again. Will try to remember to do it in future.

Re: 2007 Camry Hrybrid battery draining?
 

clearing the codes doesn't cost that much, he ended up buying the battery from the dealer along with clearing the codes. I'm assuming the reboot process was interrupted during the recalibration process. There's no such thing as mayhem when disconnecting the battery.

He could have asked the dealer to just clear the codes and keep the battery, should be less than $100 to recalibrate everything again.

Re: 2007 Camry Hrybrid battery draining?
 

Sorry about the late response guys, work got in the way.... The traction battery is disconnected when the car is off so if it is losing a charge, there has to be some sort of internal drain in the pack. By the way, according to the shop manual, if the battery is disconnected (to change it out), and the hybrid system will not start, open and close the door while in the car and then re-start the system.

Sounds crazy but but that is what they have written for that procedure.

Re: 2007 Camry Hrybrid battery draining?
 

have no fear. TCH has built in HV battery leak detection. It would have warned you if something is not right:

http://i302.photobucket.com/albums/n...erycontrol.jpg

Re: 2007 Camry Hrybrid battery draining?
 

Our car had been parked all night and all day. The outdoor temp was up around 97 degrees. My wife was out watering one of her many trees. One tree is about 10 feet from the rear of our 'TCH. When she turned off the water nozzle she started to move the hose behind the car. She said she heard a low level whirring noise from the rear of the car. I told her I guess the battery fan came on to help keep the battery pack cool.

Now that I think of it the nickle hydride batteries need to be cooled somewhat, with or without the car being driven.