I have an '06 and have been having battery problems for a while (if an interior light is left on for hours the car fails to start). It didn't seem reasonable that the battery would already need to be replaced, but that was the case. With a new one it seems to be fine now. Anyone else have a failure this soon (I have 70K miles on the car)?

 

The 12V is a tiny bugger of a battery. I'm not at all surprised that you're having problems, and a little intrigued that with the bitter cold here, that I haven't had any of my own.

 

Watch out if the battery is low on charge it will freeze then its a goner.
Beside starting the car it is also the memory battery for any keep alive circuits like door locks, lights,etc which now days have a computer to control every thing.
When the engine/car running the hybrid battery pack provides the 12 volts via a power converter, that is why it has no generator/alternator.

I have been looking at sealed battery packs from UPS (interruptible power supplies) for a replacement. Have to watch the discharge rate because of the starter motor.

 

Don't do it. UPS batteries are made for stationary situations (racks and floor stands), not impact (pot holes, speed bumps, fishtailing semis...).

 

That's why I have my interior light off. I accidentally left a door ajar all night, but because the light was off to begin with, I still had a battery in the morning.

 

12 volt batteries in my experience last 3~6 years. Near the upper limit if you never accidentally drain it, less if you do. As other responders have said, the HCHII 12 volt battery is quite small and vulnerable to accidental discharge via lights left on. We drained ours by leaving the 2 map lights on overnight.

I managed to revive it by using a 12 amp auto-charger for about 3 overnight sessions. After just 4~5 hours on the charger it was sufficiently recharged to start and run the car, but it took the overnight sessions to restore the indicator window to red/blue status. That was about 18 months back, and to date it's fine.

In your case you might have been able to recharge it, avoiding a new battery purchase. Dealerships service departments favour part swaps over maintenance, it's just less time consuming and more objective for them.

You might look into purchase of an auto-charger, in the 12 amp range. The "auto" refers to the way it charges: it automatically reduces charge rate as the battery regains capacity. They're around $40, might save your bacon with a partially discharged battery. They can also serve to warm a battery in severe cold, I think, but not sure on that.

 

Disappointing Service Bulletin I stumbled upon when I was replacing my 12v battery in the my '06 Highlander Hybrid. SB EG026-05 .... evidently the gas mileage will be decreased after loss of 12v power to the computer unless the service bulletin is complied with.

__________________________________
When the 12–volt battery is disconnected or is depleted below 7 volts on 2006 model
year Highlander HV vehicles, it is necessary to perform the ISC Learning procedure to
re–initialize the idle speed control. The information in this TSB relates to this procedure.

2006 model year Highlander HV vehicles.

 

Apparently many people on this forum have had issues with the 12V battery, and that includes me.

I recently moved to a colder climate and the battery dies within minutes if the headlights are left on. The car (and thus the battery) is only 2 years old!

 

mine died after 3yrs, ~50kmiles. bought a new one plus a solar trickle charger, and my fe has never been better.

 

how did u connect the solar trickle charger? cig lighter?