Phil

I have a '07 RX400h and when I park it at the airport for 7-10 days, I am welcomed back by a dead battery. No lights were left on or other things that may discharge the battery. I am getting sick of it. It just started about a year ago. I would appreciate any suggestions you guys might have. Thanks, Phil

salimshah

Phil have the battery tested under load?

If it passes and the battery still is unable to start few times a week, I would just buy a new battery [specially if the battery is around 3 years old].

Salim

code58

Phil- On an '07 you certainly shouldn't have to do this, but if you travel often and have to leave the car someplace like the airport where you have to call your Auto Club for service, I would suggest (at least temporarily) installing a battery shut off switch. They can be purchased rather cheaply and I would suggest putting it on your ground cable rather than the + cable. You can buy them at a place like Harbor Freight for $5.-$6. You can even install it temporarily to see if there is a sizable drain. You will lose you clock setting and it will have to "relearn" some of the computer settings (meaning it will take it a little bit to smooth out in running), but you will know if it is still drained when you return that it is a battery problem, and you need to replace. The 1st. step is to have the battery "load tested" as Salim said. Batteries often don't last longer than 3 years anymore, sadly.

salimshah

For 07, you may still be in warranty. Go to Lexus.

Salim

cav

I have a 2004 RX330 with about 80k miles, and have been having problems with my battery ever since I replaced the initial battery in Jan 2009 (the initial battery died after sitting in my garage for two weeks while on vacation). The replacement battery was through AAA. I went on vacation again in June 2009 for two weeks, and again when I returned the 6-month old battery was dead, so AAA came out and changed it out for new one since it was under warranty.

I didn't have any more problems until 6 months later when I stupidly left the hatch door open while on a trip. I thought that perhaps AAA was selling me bad batteries, so instead of going to the trouble of recharging it (I was told this would take overnight somewhere, or I could purchase my own charger) I would just go to Autozone to have it replaced. A few weeks later, the new battery died after me not driving the car for about one week, so I took it back to Autozone and supposedly I had a random bad battery so they replaced it.

So now it's one month later, and my car is dead yet again. Keep in mind that my car was in the body shop being repaired for one week (where I'm assuming it wasn't really driven), I picked it up and drove it home (about a 10 minute ride), then didn't drive it for another 3-4 days.

Unfortunately, my car is no longer under warranty as of the fall so of course everything's going wrong with it now. I've read various postings about this, and have also talked to someone, and it sounds like this is expected after not driving the car for a few days. Is this actually true (although it's a ridiculous explanation!)? It seems to only happen after not driving it for a bit. My other option is to take it to the Toyota dealership (since it is less $ than Lexus dealership) and have them check it out. However, I am fearful of doing this because (a) I'm assuming it will cost a lot just to diagnose the problem and (b) they may not even diagnose it properly and I don't know if I can trust them. I will readily admit that I am not very bright when it comes to cars - I know the basics and that's about it. Any thoughts or advice? Thank you in advance for your help.

salimshah

Let me explain the best I can.

The batteries produce electromotive-force [voltage] by a chemical reaction. As you draw current it becomes weaker. The chemical reaction is reversed when you put it on charge. When you start you draw a huge amount of current and even in standby the electronics draw current [if you leave the lights on it increases the draw]. When you run your engine the alternator produces enough current to run the vehicle [lights etc] and then charge up the battery. {you get less charging when you are driving during winter months as the lights are on in the evening**

For a viable system, the charge current must equal (and them some due to losses) to the drawn current. Once the battery gets old, it does not produce enough emf even if it has been charged.

Here is the sequence of things that should be done.
1. Have the system checked out. [battery under load test, charging system is working & there is no abnormal drain [specailly if you have an after system gadget like amps and remote starter]

2. Make sure, your battery gets enough charge time {30+ minutes for each start ... not backed by any scientific data**. For every 3-4 days of vehicle not driven, 15 mins of driven charge time .. in addition to start time {again no data to back it up**.

3. Invest in a charger {see my post on selection**.

4. Batteries are not very expensive as compared to qualified labor charge.

5. When you leave your vehicle at repair shops, they typically leave the door open and can drain the battery.

Many years ago, I picked up Reader's Digest book on how cars work .. it was printed with British Motoring Club and I think I have seen one in US with AAA. A real good book, which explains how to do maintenance as well.

Salim

ps: DUH! nearly everybody has a cell phone ... car battery is not electrically too different from the cell-phone battery. Standby and talk time and needing recharge.

Phil

I share your grief. My '07 is still under warrenty until May and I called Lexus about the problem. They said it may have a dead cell and, if so, they will replace it for free. However, if it doesn't have a bad cell, I want to know what is causing this. I have NEVER had battery problems like this until I went Hybred. Good luck on your problems. Phil

ReinyDey

Finally, after careful consideration, I decided today to replace my Diehard with a Toyota True-2 24F. I shall see how it withstands sitting around for a week or more.

Thank you all very much for your help, you have been most kind.

code58

Cav- the basics of testing the charging system, load testing the battery and testing for excessive parasitic drain are not at all difficult for anyone with the equipment and basic knowledge (you don't have to be an automotive electrical expert). Generally speaking, baring strange electrical demons (not often the case), it's pretty straight forward to determine where the problem is. I can say without hesitation that todays batteries are pretty much the WORST they can build, NOT the BEST. Makes little difference whose battery you buy (length of warranty has little to do with actual battery quality, probably pretty close to ZERO will ever last the length of the warranty and probably HALF of them won't last HALF of the length of the warranty). In addition, todays cars place a greater demand than ever before on the battery because of so many things that cause parasitic drain. Sadly, the combination of the 2 will assure that battery problems won't go away soon, and probably never. Have someone who is making a trip to Japan bring you back one from there (preferably Panasonic), you are at least much more likely to enjoy some rest from your problems as opposed to buying almost any that you can buy here. (having someone bring you back one was obviously "tongue-in-cheek")