2017 RX450h -Battery Drain

[Ben W]

Hi everyone,

I purchased a 2017 RX450h and am absolutely impressed by the quality of the vehicle and love the driving experience. However, only three weeks after purchase with around 375 miles on the odometer, I parked it in my garage for five days and when I tried to start it up it was 100% dead. Needless to say, the doors automatically unlocked, and the gas door flipped open sometime during the five days the vehicle sat in the garage so there seems to be a fail over built-in when the battery is ready die.

So I have two questions that I'm hoping the community might be able to answer. First, has anyone experienced battery drain with a brand new Lexus RX; secondly, is there any way to diagnose *why* the battery drained from information stored in the on board computer?

Thanks for taking the time to read my post, glad to be part of the owner's club.

[TrevC]

Hi Ben...welcome to the Forum

Although I do not have first hand experience with a discharging RX450h I am amazed that it has gone faulty as it is so new unless of course there is an assembly fault which is leading to the battery discharge.

Alternatively, is there any likelihood that an interior light (due to partially closed door/trunk) or similar was left on and this led to the discharge?

Equally, a battery of good quality manufacture should recover unless it has completely 100% discharged which would then have to be down to something discharging it.

Easiest way is for the engine battery to be disconnected and an amps reading taken to discover how much it is drawing and then a case of isolating different circuits to establish the cause.

Good luck with finding the cause and keep us update on the result

Cheers  Trevor

[Taffy13]

Welcome Ben

You are not alone with this uses parasitic battery drain!  Welcome aboard from my experience this is an ongoing issue with Lexus and to be honest the dealerships and Lexus customer care don't give a rats !Removed! about you and this issue's.

The remedy for the problem they told me to drive your car more often or purchase a battery maintenance charger and plug your car in, excuse me when you buy a vehicle you expect it to start every time you get into it and not have to worry if it will start.

I own a 2010 RX 350 with 50,000Km! and yes the car is parked in the garage for weeks on ends also my other vehicle which I have not experienced any issue with that one.   My first Lexus and my last! this issue has been on going from day, one sorry to be a bearer of bad news.

PS  if the Service department tells you did you leave your lights on or door ajar or anything to cause a battery drain JUST WALK AWAY.

 

 

[zmanou812]

Ben W

Have you gotten anywhere with your mystery battery drain ?

I've had a 03, 06, 10 and now a 16 RX and have not

experienced this issue like Taffy13 has.

I have had this problem with another vehicle so I was looking for an update on your problem.

 Zman

[Ben W]

@zmanou812,

I haven't let the vehicle go more than a few days without it being driven so I've been fortunate that the battery draining issue only occurred once in the three months since my purchase. Since I live in cold climate area of the US where temperatures in Dec-Feb drop well below zero it's quite possible that's a contributing factor to the battery drain issue. That being said, I'm apprehensive about letting it sit around for more than a few days and I'm not confident it won't happen again.

Regarding what Taffy13 mentioned in their "Post Script". I did take go to the the dealer and the indeed they indeed asked me if I left any interior lights or if the doors or back hatch were ajar (for the record, everything was locked up and nothing was left on). Furthermore, they also stated that this *never* happened before―then proceeded to tell me that *most* Lexus owners drive their cars everyday. I was a bit insulted that they weren't more honest, but they're a car dealership (i.e., the epitome of dishonesty with the exception of politicians) after all, so it wasn't a big surprise that Taffy13's predication was my reality.

If I do run into this issue again, I'll be sure to post again.

[zmanou812]

Ben

I too live in a cold climate and there are too many governing factors that could result in a dead battery so most just replace them to a larger newer battery

and move on. I wanted to figure out what was the cause, weak battery or was there a drain on the system from something.

I charged the battery and then put a amp meter on between the ground wire and the battery to see if there was a drain and there was.

I didn't know what was acceptable so I just hunted for the largest one.

I then started pulling fuses one by one until the drain of almost two amps changed and when I pulled the 12v outlet fuse the drain dropped to under a 1/2 amp.

I remembered plugging in an adaptor that converted cig plug to usb outlet !! so when i unplugged it the 1.5amp drain was gone.

Who knew an adaptor that went from 12v to 5v drew any never mind so much power, even when not being used.

Most people don't want to put in the effort to track it down but

you can do the same test to try and isolate the drain or get a battery maintainer or drive it more. :)

[Lexus_DK]

There is a service bulletin from Lexus on how to care for your hybrid vehicle battery to prevent it from discharging. If I find it, I will post it on here. 

[Kenn48]

I own a rx450h 2013 with 85000 miles. Drove the vehicle every day and never had a battery problem until I had to leave it at the dealership on a Saturday for service. They could not get to it until Monday. Received a nice 2019 for a loaner. On Monday they completed the service and remarked that they had to jump start the battery.  Had no time to replace then so had to wait. After a week of driving I had no battery problems until I went away for a weekend leaving the car in the garage. On Monday it would not start. I replaced the battery on Tuesday. Went two weeks without any problems until I went away for another weekend. On Monday the vehicle would not start. Battery two weeks old. Jump started vehicle and went to AutoZone. Battery checked out okay. The following weekend I let the car sit in the garage for 2 days on Monday the battery was dead. No lights were ever left on. The only thing working was the security system. I am taking vehicle back to the dealer for a checkup next week

[Les Lex 2018]

I am concerned about the electronics that is running 24/7 in this and newer cars so I did a test on the 18 after I got it.  It will take an hour charge after 3 days in the hanger.

Thee years ago, I had an insurance device put on a Camry with a new battery.  This to get lower rates for not using the vehicle that much.  It killed the battery after a week.  Reason being that some of the cell phone equipped devices use just enough power to drain the battery in a week.  So knowing that Lexus has the same concept for managing lost or stolen vehicle tracking, I needed to know what that does to vehicle battery discharge.  Based on my tests, I would not leave the vehicle for more than 4 days in the hangar if I do not drive very far for local trips. All lead-acid batterys will discharge over time due to internal resistance features, but when it takes an hour to charge it back up after 3 or 4 days, you know you have a system that requires a lot more battery capacity than the older cars.  I got a battery minder for the camry / with the tracker, and did not like it.  So I make sure I drive the RX more often.  It’s fun to drive, and - Technology has it’s pros and cons...

[markw94404]

Have you been driving it in eco mode?  I was doing that and drove the 12V battery until it had a dead cell and had to be replaced, and the new 12V battery will not attain full charge.  I started driving it in performance mode and with the engine running more, the 12V battery now gets charged. My car has been through two sets of diagnostics, so I doubt that anything is wrong with the hardware.  I would get myself a 12V battery maintainer, bring your 12V battery up to full charge and start running in performance mode.

[TexasGal]

I have a 2018 RX450h that I purchased in Jan 2019.  I also just experienced a dead battery in what is essentially a brand new car.  It isn't a cold climate thing as I live in Texas.  I had not driven the car in about 4 days.  At the dealership, I got the exact same explanation, either drive the car more or hook it up to an external charging system.  Really???  You pay $$$$$ much money for a Lexus and this is the only solution they can provide.  I appreciate this forum.  After reading Zmanou812's post about the cigarette lighter adapter drawing amps even if it's not connected to a device. I checked and I had an adapter attached to the cigarette lighter.  I've removed it and hopefully, this will address the issue.  Thanks!!

[Les Lex 2018]

On 8/26/2019 at 3:17 PM, TexasGal said:

I have a 2018 RX450h that I purchased in Jan 2019.  I also just experienced a dead battery in what is essentially a brand new car.  It isn't a cold climate thing as I live in Texas.  I had not driven the car in about 4 days.  At the dealership, I got the exact same explanation, either drive the car more or hook it up to an external charging system.  Really???  You pay $$$$$ much money for a Lexus and this is the only solution they can provide.  I appreciate this forum.  After reading Zmanou812's post about the cigarette lighter adapter drawing amps even if it's not connected to a device. I checked and I had an adapter attached to the cigarette lighter.  I've removed it and hopefully, this will address the issue.  Thanks!!

You do realize that your 12 volt cig lighter is not connected to power when the the vehicle is turned off so it is impossible for anything plugged into it to draw power.  There are other devices connected to the same fuse that draw power 24/7.  But none off them are designed to kill a battery in 4 days.  My 18 RX is a juice sucker but it’s never left me stranded so far. I had a Camry Hybrid that you really had to drive a lot too or it would suck down the battery pretty low. Toyota had the same line that Lexus used on you. Drive it more.