Will park at LAX for 13 days. Dead battery for sure?

To top Patrick's advice, replace it with Optimum battery that can deep discharge. This way, when the 12V battery get fully discharged, it won't damage (~half the life) it.

 

Is the 12v battery charged off the inverter or does the ICE have a separate alternator?

 

There is no seperate alternator on the Prius. The 12V battery is charged from a dc/dc converter off the high voltage power supply.

 

just adding this little tidbit - as I don't have time to read the entire post.
My wife parked her car at the airport on the morning of November 10th, and didn't retrieve it until the evening of November 28th. She did not experience any problems.

 

For those of you who frequently leave the Prius parked for extended periods, try something like this:

Solar Panel

 

Better have really long cables for those that have parked in covered lots.

Looks like a cool little device though, and affordable too.
Maybe those of us with solar roofs can mod it to charge the battery too!

 

I left my 2010 Prius in the driveway from Oct 13 thru Nov 17 while out of town. I tried the passenger door on Nov 18, and couldn't open the door. I then went to the driver side door, got in, started the car, and had no problems after that. I heard, or read, somewhere that this model Prius shuts down automatically after a set period of time.

 

On Page 49 of my 2010 Prius Pkg III manual:
---------------------
Battery-saving function
In the following circumstances, the entry function is disabled in order to prevent
the vehicle battery from discharging and electronic key battery from
depleting.
l When the entry function has not been used for 5 days or more
l When the electronic key has been left within approximately 6 ft. (2 m) of
the vehicle for 10 minutes or more
l If the entry function has not been used for 9 days or more, the vehicle
cannot be unlocked by a door other than the driver’s door. To unlock the
vehicle, grip the driver’s door handle or use the wireless remote control
or the mechanical key.
The system will resume operation when...
l The vehicle is locked touching the door handle lock sensor area.
l The vehicle is locked/unlocked using the wireless remote control function
(→P. 63) or the mechanical key. (→P. 541)
------------------

Looks like Toyota has taken care of the problem (except for bad batteries, which can discharge "for no reason").

 

If your 12 volt battery has gone flat 12 times, or more than 3 or 4 times it is most likely knacked and needs replacing. You can't run a lead acid battery designed for automotive use flat without causing harm to the battery. If the battery wasn't a dud when new it is now.

 

Note, if you accidently turn the headlights on AFTER
turning the 2010 Prius OFF, the headlights will stay on.

 

Just to add my own experience, parked my Mark 3 for 20 days at LHR, returned to it yesterday and happy to report it started up "on the button".

 

Okay...did this procedure work when you tried it out a week later?

 

I digitally recorded voltage and current every minute for 12 days. The results were voltage 12.54 to 12.36. Total drain 6.9 ampere-hours. The conditions were: Headlight and dome switches off, Kerr alarm activated and armed. Car started normally. Method was: 1/20 ohm precision 4-terminal shunt wired between battery negative post and battery holdown bolt before disconnecting the battery negative lead from chassis. Voltage measured from battery positive post to chassis. The data acquisition unit has a precision of 1 milliamp and 1/50 volt. Details at:
Measuring Instrument with an Optically-Isolated Analog Input

 

My 2010 manual says the smartkey system is automatically disabled after 5 days to save the battery -- so you don't have to do it manually.
Yet by some trickery it comes alive again when it needs to. The whole thing is a big computer, sort of a giant laptop with wheels -- and the operating system quirks are obscure in the usual way.

 

I have left the Prius for over 30 days while out of town. I have had no problems getting started again. The only thing is the unlocking works on the driver's side.
Ken Tak

 

I've left my Gen2 Prius parked in front of my place for a month without driving it. No problems.

 

Purchased new 2010 Prius III with solar roof and Nav. in June.
Drove car car minimally for first 2 days of ownership and then drove to Charleston International Airport and left car in longterm lot for 6 weeks. Did not do any key disabling/battery disconnection/etc.
Returned 6 weeks later. Remote keyless unlock worked normally upon touching door handle and car started without incident. Drove away without another thought about the issue.

 

When you pull on the door handle, the system realizes you are there and re-enables the SKS. If it's night and you are clever, you might notice that the interior lights failed to come on as you approached the car. Other than that, it's pretty transparent.

Tom