12v battery questions

290807 = 29th Aug 2007

Outside of the US, much of the world uses dd-mm-yy for date codes.

 

Nope. 290807 is the code for ethylhexyl methacrylate.
Its on alot of batteries.

 

Thanks for the info Ed. Now that I think about it, my date code wasn't stamped directly onto the battery like that. Mine was in the same format (261104 = 26 Nov 2004 in my case) but it was on a separate little white rectangular sticker that was attached to the top of the battery. It looks like in the OPs case someone has removed that sticker.

 

i would check the voltage and if it's not marginal, keep on truckin'! if a dealer installed a new battery, any dealer should be able to see that info.

 

Here's what I would do:

Keep the battery. What you have is a replacement battery installed sometime after the TSB (or recall) came out to replace the original 12V "GS" battery (identified by big "GS" letters on the front). It (the Panasonic you have) was an upgrade to the original battery. My experience with the lesser GS battery was a 10+ year service life. When I finally replaced it, I did so not because it was causing problems but just for good measure. I still have the battery and I am confident I could charge it, reinstall it and use it for who knows how much longer. The 12V battery is only used to boot up the computers and run some aux functions once the car is in ready. It gets charged by the traction battery through a dc-dc converter. If it does go bad, you will see some crazy things happen in the electrical/electronic system that are unexplainable (ie: check engine lights that come up for no reason or other warnings). The strain or demand on the 12V is minimal which normally results in longer life.

You can go here (http://www.toyota.com/owners/web/pages/home), register your VIN and find out any service history, done by dealers (which would hopefully include your battery replacement date).

Welcome to the proud Gen I community.

 

The 'seat of the pants' test for the 12v battery is to press power without foot on the brake twice and see how fast the power windows work, then press with foot on brake and see if it is faster.

 

Great advice for a Gen II but, he has a Gen I (no power button).

 

Hooked up to a decent digital multi-meter a healthy 12 volt should be showing around 12.6 volts or a bit higher: 12.7~12.75. If it's ailing it'll be around 12.4~12.5, or lower. Also, a freshly charged battery will give falsely high readings: you want to drive it around a bit first before checking, maybe with headlights on.