12 volt battery drained

First, find out what the typical standby current is. 50mA is high, but acceptable by Toyota's standards. 23mA is more typical.

Also a capacity test should be done on the battery to be sure it is holding a charge.

I think I may have found a possible intermittent drain source though, that I need to investigate.
One of the bigger possible power consumers while the car is off is the hydraulic brake pump.
I was hearing a very very faint whine or whistle that I thought was the flourescent lights in the garage, but sound remained when they were off. I am suspecting with 5% certainty that it may be the brake pressure leaking back to the low side, which would soon require the pump to reactivate. If this happens often enough, that would drain the battery.
I suppose an analog clock connected to the ABS relay could count the amount of time that the pump engages.

There was talk that the JBL amp sometimes develops a drain, may want to look into that as well.

One thing to consider: About all the components in the car get their main power from the unswitched 12V line, but also have a power source of lesser current switched on at ACC, Ig1, or Ig2 (ready) to 'wake it up'. Being this the case, any device could get stuck on or partially on.

 

Figure I ought to chime in here as I was one of the first with the dead 12v battery and fought with various dealers for almost five months trying to get it resolved.

The last trip to the dealer (the fourth and final before I "Lemon Lawed" the thing) seems to have resolved my problem. They replaced the JBL amp and I haven't had a problem since - almost three months now. I'm ready to declare this resolved and chalk it up to a bad amp.

If you have the problem again I strongly recommend leaning on your dealer to look at this as a possible fix before they tell you nothing is wrong. I went through months and months of dealer denial, and many no-start situations before this was finally resolved.

Geoff

 

Is the SKS turned on? That would prevent locking with the black button. If it is on, did you get a beep error?

 

Also are you sure all the doors and trunk hatch were completely closed when you tried to lock it? I don't have SKS so maybe this doesn't apply, but I recently was unable to lock my car with my remote, though I could do so with the button inside. The problem was that one of the doors was slightly ajar.

 

If a door is open, it will give a looooong beep when you press the black button.

 

Ah, you used the remote. Originally you said SKS, which means pushing the black button.

It depends how and how often it is used. It is a standard lithium (usual formula) battery the size of a quarter.

 

Dan,
Regarding the noise you heard, long after the system was shut down , I presume, and you suspect the hydraulic brake pump. Is is possible it was the storage tank pump? I have some info contained in a Toyota Tech magazine which states:
Note:After 5 hours have elapsed with the power switch off, you may hear the storage tank pump operating. This occurs when the ECM has detected a problem and needs to check the heat storage performance of the coolant heat storage tank.
Just a thought but then I guess you are quite familiar with the pump sound.

 

Well I thought is was just a problem with our Prius. Ours has went dead twice now. The dealer we bought the car is 110 miles away. When I called him the first time I got the story of the rear hatch being left open. When we jumped the battery there was not a light on any where. The car ran fine for about two weeks. My wife is on Dialyse and she went to the hospital after she was done the car would not start. I called the dealer and said it happened again. He said they would have the car towed to the dealer but if the battery checked out Good I would have to pay the tow bill. I called the factory rep and was talked to rudely. She said the dealer has to have the car to check it out. I cant afford a large towing bill or be with out the car for a couple of days and then try to find a ride to pick up the car. I don't see Toyotas faith on this problem. Our car is a 2005 with a package #6. We currenty have about 1200 miles on the car. Any Ideas would be a great help. Thanks Jim and Donna

 

The faint whistle/whine I heard was within 5-15 minutes of powering off.
Further pondering has me thinking it was the AC refrigerant settling.

 

Cite lemon law. There has been a few reports of strange battery drain, so they do need to earnestly investigate. One was an intermittent JBL amp.

 

Regarding SKS, here's a good test. First, be sure SKS button has SKS enabled. Second, observe your fob when using it. Does a little red light blink when you push the lock/unlock buttons?
If that proves positive, try working with SKS (lock with black button, unlock with touchpad). You should see the LED on the fob respond with SKS requests. If LED is flaky or not happening, esp with remote buttons on fob, replace fob battery.

If SKS sees a problem, it will beep an error.

 

I don't know if it's just the salesman providing his opinion or what, but last night when he was going over the features of the car, he pointed to where the 12v was. I mentioned how people were having problems, and he said that there have been reliability problems all along with the gel cell batteries, and that it, if anything is the one "problem" with the car...Again, probably more salesman opinion than fact, but then again I didn't even realize until last night that the 12v battery was a gel cell...

 

i don't think it is a gel cell. It is a sealed, vented lead acid. Some have discussed about replacing it with a gel cell.

 

Aux. battery is a valve regulated lead acid glass mat battery. It apparently is sensitive to high voltage and a standard battery charger should not be used to charge them. Without an excellent voltage controlled charger you can use a trickle charger as long as the amperage is kept below 3.5A. A jump start is OK and allowing the Prius charging system to restore battery to normal SOC. Just thought I'd throw this in 'cause I think this information is important to us.