I am a new owner of a Lexus SC 430; 2002. Battery dead after two weeks of no use. Replaced battery and noticed the clock stays on with ignition off and doors locked. I did not notice or aware if clock remained on three weeks prior when purchased. I'm thinking this caused the battery issue. Anyone know a fix for this?

 

Moved to 2SC forum.

 

There are lots of reasons the battery could have gone dead, but the clock is not one of them. The clock won't draw enough current to kill the battery in a year.

Several things have been accused: leaving the headlight **** in auto, leaving a door or trunk ajar, ECUs whose capacitors are going bad, etc. Place an ammeter in-line with the battery and see how much parasitic current is being drawn once the vehicle is off. If the number is high, you'll need to track down the leaker. (This is somewhat common.)

 

It is a common complaint amongst all SC owner's. Leaving your car un-driven for a couple of weeks, makes the battery too weak to start the car.

You can follow Harold's excellent advice and turn your automatic lights off and lock, but not arm your alarm. Or you can put a trickle charger on your battery.

I do the first two and can usually get by without driving my SC for a month, before my AGM Battery gets too weak.

Google "clublexus.com SC430 battery" and you can get a full run down of the situation

 

Some of it seems to be the luck of the draw. My 2002 SC430 never had a problem, so long as map lights were turned off and doors & trunk were properly shut. Mine would last more than 2 weeks easily. But there are several on this forum that haven't been so lucky. Some of them got better when turning the listed items above off. Others have had ECUs with parasitic current draw well above spec. Others were never able to narrow down the suspects. Also, do you have any aftermarket components like radios (electronics in general) on the car? If so, then those could also be behind the problem.

 

To answer OP questions:
1. yes, the battery does discharge after 2-4 weeks of no use.
2. yes, it is normal for the clock to stay on, which is only a minimal power use.
3. to fix this, try disconnecting the negative (not red) cable from the battery when car is parked for over ten days. Usually, just driving for 30-50 miles recharges the battery for regular daily use.

 

I’m currently on the 6 week vacation. I forgot to put my battery on the tender. I’m sure the battery will be dead when I come back. If it is not then it’ll be a miracle.

 

This is an issue with most older model cars. I had the same issue with my 98SC. Two weeks and done. Gotta drive it or use trickle charger. I tried solar panel trickle chargers but those never work.

 

Was that pun intentional? If so, good one!

 

Good catch.

 

So, there was no miracle. Came back from the vacation and the battery's dead as it can be. Had to jump-started and recharged.

 

A trickle charger would have helped. I have 2 trickle chargers permanently installed on my 2 bay garage. When I go out on vacation, they are plugged in. If I do not use the car for a couple of days, I plug it in. Knock on wood, both permanent residents of my garage have 5 year old batteries and are still cranking good. A maintainer is very helpful with battery life.