We replaced our 2008 RX this May with a new 2018 RX350AWD. In just 2+ months of ownership, the battery has failed (died) 4 times. After charging it on a charger, it seems to work fine for awhile. No inside light was left on, no door was left partially open, ... no key fob was left inside the car to drain the battery. Dealer can't find nothing wrong either and said the battery was good but something was wearing it down. The RX is used primarily for short in town driving with days we don't use the vehicle at all. Dealer said we should drive the RX daily to keep the battery charged due to the many "juice eating" accessories that are constantly running in the background draining the battery the way the dealer explained to us. Our driving habit hasn't changed and never had an issue on our old 2008 RX dying on us. Our neighbor also has a 2018 RX350AWD but bought it when it first came out. He's had similar dead battery issue with his and he has lost count how many times it happened. He too checked for any lights left on .... and everything was fine. And he drives it daily. So far the dealer has not been able to determine the cause of the frequent drainage. Has any of you who have same vintage RX experienced the same battery issue? If so, how did you resolve it?

 

A parasitic battery drain is when abnormal and continuous discharge of power occurs after having shut off the engine. Usually, this is caused by a short circuit or an electrical device that remains in the "on" position or energized, such as:

• A trunk
• An under-hood or a glove-compartment light
• A switch
• A computer module

But a battery power drain can also be the work of a bad alternator diode or even a faulty battery.

Depending on the amount of current being drained, a parasitic draw will suck all the juice from your battery in a few hours or minutes.

Here, you have four tests to help you find the culprit:

1. The amperage battery drain test
2. The voltage drop battery drain test
3. The bad alternator diode test
4. The car battery hydrometer test

 

My 2017 RX350 sits in the garage for 1-2 weeks. Never fails to start right up. It's almost a year old and has just turned 4000 miles. So, I'd say you have a parasitic drain from something.

 

Here can you do this or better still give to the dealer - sound like they're useless and/or couldn't care less.

https://www.wikihow.com/Find-a-Parasitic-Battery-Drain

This is very simple stuff, unfortunately dealers are simple too - don't know about the US but here in Australia it's common for the "trickier" problems for dealers to be taken to specialists (in this case auto-electrician). Being a new car and as long as it's not an accessory you've installed (dash cam, radar detector,etc) the dealer should definitely be putting in the effort to repair.

 

Start documenting each failure...is this lemon law eligible? I am sure the dealership will work harder to find the issue once you tell them it will soon become their problem.

 

Do you leave the car unlocked or leave the key nearby? It is possible for this circumstance to keep the car in "ready" mode and drain the battery more quickly. I have seen it in Subarus but haven't seen it reported on this forum yet.

 

My '17 RX350 has been suffering from battery drain to the point if it is not driven for four days, it needs a jump start. I have replaced the battery twice. A local mechanic said the alternator and the charger are working fine, so there is a parasitic drain somewhere. But he seems to be reluctant to do further diagnostics. He just ran down the clock twice by working on other vehicles while my vehicle stood outside.

Are there any reputable shops in and around Chicago that can find the problem without charging an arm and a leg?

FYI: My SUV has three aftermarket accessories; a Carplay box (which I feel is the culprit), DashCam, and a Remote Starter.

Appreciate any suggestions/recommendations.

 

"...in and around Chicago" is a little vague and covers a huge area and thousands of repair shops. Ask around where you work if anyone knows a local reliable shop. Talk to people at church, relatives, neighbors or where you shop. Someone will know a good place to have your car repaired. Everybody has had to take their car in somewhere for something.
A parasitic drain is normally NOT a major issue unless there is a short circuit buried in the wiring somewhere.
You had bad luck with the first mechanic but the next one might be excellent. Somebody on this forum might know a place to go in Chicago. It would help if you indicated what part of the city you are in.

 

If you are on your third battery and it's only lasting 4 days, then it strikes me that this problem may have always existed on that car, unless you have well over 100K miles on it already. My 2018 has 53K miles on it, and it's second battery is 2 years old (and I didn't wait until the OEM battery became a problem to replace it). Or possibly, if your dashcam is set to a mode that starts recording even when the car is turned off, plus if the carplay box has a clock or something that is always running, perhaps those two are both culprits.

 

Are you at all mechanically inclined? If so, perhaps you could find what fuse powers your Carplay and pull it and see if it's the problem. Otherwise, you'll have to find another shop.
Good luck.

 

I am in the Lincoln Park area.

 

Yes, my car has more than 100K miles. When the problem first surfaced, my vehicle was four years old and had about 90K miles. So I replaced the battery. The car was driven regularly after that, so the problem did not recur until I went on an overseas vacation for two weeks. So I had the battery replaced under warranty.

I WFH most days for the past two months, and the battery drain has become a bigger problem.

And yes, the dashcam is programmed to record even when the vehicle is shut off.

 

I can be mechanically inclined under certain conditions. But for this job, I do not feel confident in my abilities.

 

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Disconnect what you have installed and see if that solves the issue.