tfischer

My understanding is that new cars with all the electronics and modern wiring do not exhibit the signs we used to see that would indicate a weakening battery. In the old days, cranking the car with a weak battery would dim the lights and the engine would turn over slowly. That hardly happens any more. The service technicians tell me that today the battery can appear fine one day and not have enough juice to turn over the engine the next.
Also, when the battery is too discharged to turn over the engine it may not be too low to keep the clock running or to unlock the doors or to keep the little red dashboard light flashing. However, it can get dead enough to stop the clock, at which point it's really dead.
Without those warning signs, it's a lot harder to know what's going on. Looking at the battery's voltage is one way (only) to get some idea. There are voltmeters you can plug into the socket in the center console, but readings at idle are not helpful, and when you shut the engine off, the socket goes dead. Switching to ACC is bothersome. Putting a voltmeter on the battery terminals is the best; I have a Battery Tender with the external connector which allows the Tender to be attached without raising the hood; this allows a quick way to easily test voltage at the terminals, and I used that a lot while I was monitoring things before my problem was solved.
Lexus checked my car in detail several times for parasitic leaks and other electrical problems and could find nothing. We now know my problem was a bad original battery and a bad replacement battery, even though these batteries passed most of their tests after I drove the car to the dealership. The third battery has the car working perfectly - in a month it has not lost more than 0.04 volts.

mjeds

"sitting for weeks at the dealer"




that might explain the dead battery issue,
can't speak for your dealer but I noticed yesterday when I took my RCF in for it's 5,000 service and a firmware flash for the enform system freezing, that the key stayed in the cup holder the whole time they had my car on the lot waiting for a technician, it took 4 hours for them to do the service.

I stayed in the area my family and I walked to Santa Monica Pier, we came back at hour 2 so I could grab my sunglasses, one of the advisors walked me to my car which was still sitting where they parked it when the porter took it and the key was in the cup holder.

When I picked up the car I asked the service advisor about it and he said that typically the keys will stay with the car during the day, and they collect them all at night from any vehicles that are left overnight.. Apparently they do not hang them on a key rack like the old days..

So your key in your car for 10-12 hours a day while it was in the dealer possession may very well be why your battery is flaky now..

If they killed it, they probably just used a booster to jump start it when they returned it to you.

JCtx

I know for a fact the keys are always stored in a separate locker, far away from the showroom. I asked for it to quickly listen to the ML sound system on what's now my car. I asked for a new battery when I bought it, but they declined. I 'reconditioned' it when I got it, and haven't had a problem until that day. But didn't like not only my car wasn't fresh off the truck (the way I buy most of my cars), but that it sat at the dealer for 3 weeks inside the showroom, with people moving seats, leaving lights on, etc. It also had some scuffs I didn't see before that bother me and couldn't completely remove, so never again.

Anyway, I have the best Optimate battery charger that checks battery condition before starting charging cycle, and even though I heard that damn pump yesterday go at it for about 5 minutes, I just hooked it up now and it was solid green, so the pump doesn't discharge the battery noticeably when running 5 minutes. What could have been the problem was my tank was supposedly almost empty. Who knows. I wanted to know how accurate is the fuel gauge. Let it go down to a range of 20 miles, and could barely pump in 15 gallons, after the pump clicked several times, and fuel was almost running out. I don't typically do that, but just wanted to make sure it was really full. That means there were at least 3 gallons in there, which is not what I expected. The useful amount of fuel seems to be 15 gallons at best, not 18.

Will call dealer tomorrow to see what they say about changing the battery, even though it's perfect now. Don't want to waste my time traveling the 40 miles only to get rejected because it shows good (I know it's good now). I'm okay with electronic gremlins... which I get in every car I've owned in the last decade. But not when the battery goes flat. The other thing is with the new super smart chargers (BT+ is not), they don't go solid green when there's a bad cell. But also know even a little voltage fluctuations can trigger all kinds of weird reactions, so it could very well be. A catch 22, since dealers want to duplicate or verify problems before doing anything. I think what I need to do is leave the car sitting for a week, without charging it, and see if it dies again. I used it for the last 2 days, on several short trips, and it started perfectly. I can tell by the cranking speed battery is fully charged. Thank you for all the comments gang.

chaosrob

my car sits for a week or two sometimes between starts, no issues at all

keithS

Same here, no battery issues.

tfischer

The RC does not seem to have battery issues. Nobody at my dealership has this problem, and this is the first post I have seen in a year on any Lexus owners' forum. Since we now know that my problem all along was a series of two bad batteries in a row, I think it's pretty clear that the car has no tendency at all toward battery problems. This problem was just some bad luck on my part.

WayneIS350

I had this issue once on my RCF. I was out of town on vacation just over a week. The battery was dead and wouldn't crank the car.

I called Lexus roadside, who charged the battery enough for me to crank the car. The roadside tech said the battery tested good.

Nothing was left turned on in the vehicle, but it hasn't happened again since. It is a concern when I go out of town on business for a week+ since it has happened to me once already, just like the OP.

tfischer

Surely, Wayne, you don't want us to generalize from insufficient data.

mjeds

@ the ~20 mile range the car still has 2.5 - 3 gallons in it. .


every car I own I run the tank completely dry as to know exactly how far the car will go, my RCF was no different.


I ran it until it stalled, I had 1 gallon with me, fueled and drove to gas station at which point it took 17.8 gallons before it clicked off, and I was able to top another .5 gallons.




as for the key storage, I misunderstood, you meant when you purchased, I was talking about at a service appoint. At my service appointment the key stayed with the car.

WayneIS350

I am not saying the problem is wide spread. But the title of this thread asked had anybody else had this issue, and I had an experience similar to the OP.

Just like the fuel pump issue, some owners have had it, many others haven't, but that doesn't mean it isn't a concern.

Discussing our experiences with this car is the purpose of this forum, is it not?

canadalexus

I have experienced a similar issue as the OP. I parked the car for five days and battery was dead. I believe it could be due to the fact I was working in the garage for 2-3 days near the car with the key in my pocket and temperature dropped significantly during that time.

tfischer

With all the electronics in the cars and the keys, it can be hard to tell what's causing the problem of a dead battery, as it's difficult to recreate the circumstances and environment that existed at the time. If it recurs, then you need to start looking at various causes. We thought it was several different things in my car, but each time it became apparent that we were wrong. Good luck.

JCtx

Hey, good to hear there're at least 2 more in this club. And both of you still have the original battery, correct? Mine charged completely as well, so no sense in trying to get it replaced at this time... but will call dealer again, to make sure it's documented.

As a side comment, leaving the key in range shouldn't kill the battery at all, since the car goes into 'deep sleep' at some point, meaning you have to use the remote/key to unlock the car. I've tested many of my other cars leaving keys inside for over a week, and batteries were perfectly fine, with only the discharge expected. We have no choice but to wait for at least a second time. Still hope this was just a one-time fluke. I've had many, many of those over the years, attributed to 'electronic gremlins'. Nature of modern, electronic-intensive beasts, I guess.

Hey, so how many miles after 'zero' range until the engine died? I'd like to know that very much. In case I ever need to push the range (not on purpose, of course). Thanks man.

red93sc

You may have the same issue I have.
I almost had the same issue with my RC.. I noticed a sound coming from the rear of the car while sitting in the garage over night. This was after exiting the car the car the night before with the ignition off and doors secured. I narrowed the sound coming from the rear area of the car by the rear tires. I am not sure its a fuel pump or some emission device. I do know its an electric motor.

If I didn't catch it by the next day, I am sure my battery wound of been dead within a few days.

This has happen sporadically times with in a 3 or 4 month period.

Temporary Solution: Turn ignition on and back off. The sound of the electric motor turns stopped.

Pay attention to the sounds of your car when exiting, it should be totally silent. NO electric motor sound for sure..

Next time it happens, I plan to video the occurrence and provide it to my dealer for troubleshooting.