Just had the batter replaced last week in our 06 GS300.
My issue is this is the 3rd battery that's been needed in the 6 years we have owned the car.
I have never had a car that needed 3 batteries in 6 years. Either something is wrong with the car or the batteries JMLexus is using. They tell me nothing is wrong with the electrical system but I remain skeptical.

Anyone else having this problem?

 

My battery just died on me yesterday after the car being in accessory mode for maybe 10-15 mins. Dealer checked it for free but maybe an upgrade on the battery is in order for me.

 

Maybe get the alternator checked out. Could be a malfunctioning voltage regulator.

Grounds are another good place to look.

 

Access to a DC volt meter or a multi-meter? Easy test will get you in the right direction.
You should see from 13.8 - 14.4 V across the battery terminals with the engine running. Voltage between these values points to a battery issue. Anything less than 13.8V you have a charging issue.
Get the battery out & take it to an auto parts store. Have them put a load test on it. This will tell you the true condition of each cell.

 

Obviously something may be intermittently happening with your cars electrical/charging system but I doubt it (IMHO).
Car manufacturers and dealerships don't always use or better yet get the best batteries. Out of the last 4 new cars in our family two of them had 3 batteries in 6 years as well. In both cases the factory battery only lasted a little over a year and their replaced "dealership" battery lasted less than three years. The third I replaced with a known over the counter battery, one was actually from Walmart thus less expensive and both lasted for over 4 years and beyond (sold vehicles etc.).

I can't sit here at my keyboard and rule out your charging system but my guess is you have just been receiving subpar batteries - of which hopefully have been replaced free or with a good prorate etc.

SteveCraig, is the charging voltage really that high (min of 13.8)? I have yet to explore this on my GS yet typically an alternator/voltage regulator can easily dip down in the mid to upper12s with a charged battery and very little load etc. Now if the AC is running and headlights on or more, definitely 13s.

Cheers

 

Yes, the last 2 were free to replace but I'm more concerned they needed to be replaced. It's probably subpar batteries but I will let someone else check the electrical system.

 

14.4 would be the extreme high side, while 13.6 - 13.7 would be the extreme low to fully charge an automotive 12V battery. Manufacturers instructions will vary. Curb idle with everything off. Additional loads will see voltage drops at curb idle speed.
A big issue to consider when replacing a battery is the source of the lead in the plates. Virgin lead will demand a higher price than recycled but will ultimately give you better battery performance & life.
The load test I mentioned is the ultimate "acid test" to show true condition of the battery, once it's established it's even being charged correctly.

Late reply. Just got in from Halifax with our new to us RX350.
What a wonderful car to drive on the highway!!

 

The Lexus brand battery sold at dealerships is usually a re-branded Interstate battery, and not the best one they make either. I've seen many fail around the 2 year mark. But always good to check for a parasitic draw.

 

short trip also slowly kill the battery. The battery get drain with every start of the car, in order for that charge to put back the car need to be driven more than 15mins. Else the battery will prematurely die.

 

Well that or put on a charger every once in a while - but a good long drive with a healthy alternator should leave the battery fully charged up.