Originally Posted by PERRYinLA

Speaking of Costco, that's where I just bought my replacement battery (group 24F).
Cost $99 + tax, but you get $15 back if you give them your old battery.
It comes with a 42 month full replacement warranty (but, unlike Walmart, there's no pro-rata afterwards).

I needed a new one because, as mentioned, the Smartkey search kept draining it until it would not take a charge - I got 3.5 years out of it, where the Walmart battery in my SC400 is still working, despite a manufacture date of 12/2010 - that's 6.5 years and counting! (No smart key on the SC, though.)

This Smartkey issue is covered in detail in another thread: https://www.clublexus.com/forums/ls-...-problems.html and page 34 of the manual.
No need to disconnect the battery - there's a button way under the dash, slightly to the right of the steering wheel axis.
It's quite a reach, but you'll feel it, along with another button and ****. The button that disables the Smartkey function is the button closest to the front of the car, and when it's in the depressed position, the Smartkey function is OFF (you can tell that also from the "Key" light on the dash being off).
Once you do it a few times you'll know exactly where it is, just by feel and I'm already in the habit of disabling it once I park it in the garage.

Time will tell if it helps extend the battery life.