The vehicle draws a minimal amount of current to keeps itself "alive" - and waiting for you to return. Leaving it overnight or even for a few days should not reulst in a drained battery.

Doors, interior lights (headlanmps should be "auto off") and the like (not sure about the back hatch, but I would confirm that it's closed anyway) are the most common culprit of drained batteries, but if this persists (and you are sure that the above conditions are not existing) I would contact the dealer again. I'm not sure if your insurance covers the tow (or the dealer?) but having it towed to the dealer while it is dead might provide them with some added reason to find the cause.

The bad part about this is the you are out the car - and maybe more importantly - your time - while this being done with no guarantee that it will result in a resolution.

 

It would be unusual for a factory equipped Toyota or Lexus product to have a load that would result in discharging the 12 volt battery in anything less than a week or so. Have you had aftermarket audio work done? remote start? EBH..??

If you're not used to the Toyota/Lexus door ajar technique it takes awhile to form the habit of religiously checking that the interior lights extinguish when you close the door(s). Especially problematic with those interior light off, fade out, delays.

 

No I did not have any after market features put in the HH, though I am considering an auto start. I am not familiar with the door ajar technique.

 

Here is a little experiment I just performed on my 2008 HH.
Put digital voltmeter on battery (nothing turned on)...............12.46 volts
Pushed POWER button once (radio comes on).........................12.14 volts
Pushed POWER button again (dash lights up).........................11.86 volts
Pushed POWER button with foot on brake (ready comes on).....13.92 volts
Wait about 15 seconds and engine starts................................13.96 volts

This tells us that the 12 volt battery is charged by the traction battery through the inverter only when the system is fully on.
I don't think the ready light will come on if the 12 volt battery is dead.
Also remember that the M1 motor acts as both an alternator and a starter motor, there is no starter or alternator in the conventional sense.

 

I'd be willing to bet...

The next time you need a "jumper", provided the hybrid battery SOC allows, just connect the foreign battery long enough to turn the system "on". Then remove the "jumper" and see if you're not "set to go".

 

I've had a '06 HiHy for a couple of weeks, and it has been well behaved so far, regarding battery charge levels. Since yours is so new, the problem you are having could well be a factory defect (yes, these can happen with Toyotas, just like any other car!) - a sneak circuit that is discharging the battery when the car is off. If it continues to happen, you may need to leave the car with the dealer for a couple of days, so they can observe it to see if they can reproduce the problem. From auto industry experience, I can tell you for certain that wiring problems are the #1 warranty issue for many car manufacturers, and these can produce the symptoms you have described...

 

I just came on here looking for this issue. This morning my 96 hyhi would not start. I just got it a few months back and have had a few issues with it. It would not turn on this morning and the battery light was on (two battery lights). I realized, sitting in the car, that the overhead was on. I opened and closed my door and it still stayed on. I opened and closed the passanger door and it went off. Clearly that door had not been completely closed, left the light on all night, and drained the 'little' battery. I did not realize that the big battery will not kick on if the little battery is dead.

I will get the 12v starter as a backup for such an occasion. The car did start just fine and quickly after a jump. I wish I had known this issue before today but hopefully your post will help us all ;-)

Thanks

 

Sorry. Of course I meant '06 not '96 ;-)

 

Umm interesting thread... my 2¢
My son switched on the rear interior light - overnight - no problem starting the next day.
Rear doors on my HH have a habit of not fully closing when the children get out - good cabin air seal. Hitting the remote to lock the car warns me if a door is ajar, continuous tone.

 

Hello Kitkatinfl,

Have you noticed any difference in performance since your battery died? Did you take it to a dealer afterwards to have it checked out?

Christopher