The battery will drain down because the computer is always pulling a little current to save it's memory. One thing you will have to do though is when you re-hook the battery, make sure to turn the key on BUT DON'T START IT. Leave it on for a minute, then restart it. Toyota's have a problem restarting after a new battery if you don't follow this step. Also, an easier fix for you might be getting a slow charger to leave hooked up to battery for the time it's being stored. Many battery chargers will shut off after the battery is fully charged, then come back on when it needs charging. Good Luck!!
CR2032
It's a group 34 battery.
From $65 to $265 depending on the quality battery you buy.
There could be several reasons why a Toyota Sienna will not start. the most common problem would be a dead battery.
530 cca and 575 cca
If they sell batteries, then yes.
24F or 35 Just ask for the number from any places that sale battery,
A failing alternator.
check the battery
The tank that is located under the battery on a 2004 Toyota Sienna is a windshield washer fluid tank. Toyota put this tank in this position on the 2004 to 2010 models of the Sienna.
Sticker "promised 28" mph Hwy....Bet they had a good laugh over that one. THE Best we ever got on extended HWY trip was 21.5 mph (V-6 Sienna). LAM
Check you battery, when it starts to die esp on hot days.