I might have gotten rid of my RX450H+ due to the same problem, but myself and many other RX owners, have found a $100 solution that allowed us to live fine with the Lexus. See the link about the solution, which enables us to be always covered against any battery issues, without having to manually open doors, call roadside, or any such hassles - just fire up the App and solve a dead-battery problem immediately.

https://www.clublexus.com/forums/rx-...l#post11806331

 

I have to admit this very reasonably priced product provides plenty in the way of convenience but it doesn't look like it will save your 12 volt battery at all from degrading health and it's ultimate demise unless you begin to utilize a battery tender to maintain your battery health on your infrequently used car. This is the result of the root cause for the drain, consistent parasitic losses while your car is left unused.

The 12 volt will still be left to drain and drain below a healthy limit of just shy of 12 volts where upon the cells will begin to be degraded and never recover their health. Ultimately leaving you still with a dead battery if you drive infrequently enough to allow the battery drain to continue unchecked. At some point you'll still need to buy a new 12 volt - or at least stick Lexus with a warranty claim to replace it, which I strongly propose everyone do if at all possible, to make Lexus feel the financial pain of their bad design.

For all who cringe at the reality of nowhere else to turn to when forced to leave your car sitting for a few weeks while you're away on either business or pleasure trip and have have no alternative except the much loathed call to get a boost, this is a happy and most likely is a much safer alternative to deal with a late night or an unsafe location when you're stuck with a dead battery. This is the darn point we need to force in Lexus' face whenever we can get a chance. Tell the service manager, the sales manager, the dealer owner etc that they need to move on this as the owners have no other recourse to eliminate or resolve the core issue here. Your practically brand new luxury car works like crap when it comes to the simple task of maintaining a 12 volt battery, a key and core required component of an automobile since they removed the HAND CRANK TO START IT!

BTW Black Friday sale is on for this as of Nov 22 2025

https://lithiumhub.com/product/emergency-start/

 

While I agree Lexus needs to feel the financial pain of their bad design, I don't think they ever will because they have already asked their dealers to do a simple 12 V battery test when customers complain, and will not replace the battery unless the battery actually fails their test. They have figured out that current Lexus owners will continue to buy Lexus no matter what, so they have simply decided to replace batteries when their battery fails under warranty. While I can't see myself as buying another Lexus for a multitude of reasons, at least from the reading this forum, I'm also reasonably confident that Lexus' business assumption of milking their current/future customers is actually quite valid - there are far too many people in this world who will only buy Lexus, no matter what.

And you could be right that the batteries for non-frequently driven cars will fail eventually sooner than usual due to this poor design by Lexus - its a manageable problem, by replacing those batteries for $180 or so every 3-4 years, while using this Ionic gadget together with its app.

 

Sadly wrinkle, your sentiments are shared with many Lexus owners as of late. I would hope that owners use their voice as much as possible regarding this subject matter. Seems like practically all makers of hybrids and plug in hybrids have forums where this battery issue is real too. The RX forum alone has of this posting date almost 190,000 views. I'm guessing not all are owners, possibly some are or were prospective owners whom have now walked on past Lexus for their next purchase. Car reviewers on YouTube are bringing this up now, news articles, digital car magazines etc. It may take some time but I'm optimistic car makers will listen eventually. It only took like 5 years of moaning before they realized piano black is best left to pianos!!

Here in Canada we've managed to convince Lexus to add more anti theft measures into the '26 RX and NX after 2-3 years too, so they do listen when they're piggy bank is threatened. The RX was being stolen at a rate of over several thousand a year here in Canada, people wouldn't buy them when being given insurance quotes of over $8k a year for them. Then Lexus woke up. Everyone now is waiting to see whether rates will come down. Money talks still.

A simple battery check done by a dealer is still something that hit's the dealer's and Lexus' bottom line too. I was promptly told if my battery test came back good, I would have to pay $89 for the test, well they didn't get my money that day, Lexus would've had to reimburse the dealer for their time and pay to install the new one and eat the battery cost too. When a dealer is calling up owners to ask about replacing wiper blades and key fob batteries you can understand how deep the greed goes!

 

This looks interesting, and I might have considered it, but my Lexus is leased, and I am reluctant to make any modifications to the car to avoid turn-in issues, assuming I keep it that long.

 

Its not a modification - simply an attachment to the battery posts with a couple additional nuts and a velcro. I take it off every time (takes a couple minutes) I take it to the dealer for servicing recalls, for example.

 

All of the above is excellent knowledge!!! Thank you for sharing this.....the annoyance of hooking up a charger (of which I have 3 on my old cars) seemed to be out of place for the Lexus.

Just bought 2 units for my 2024 NX450H+ & 2020 RX450H - with the 25% current discount and the upcoming Black Friday Deals these seem to be a great solution. Got to the LithiumHub website - cheaper than Amazon even with the added Shipping taken into consideration after the Discounts. Bezos has enough money...

I am in AZ so batteries rarely last more than 3-4 years here. My wife got stuck once in the NX recently and it was the low 12V battery scenario from driving it so few miles.

Let's see!

 

Toyota Lexus Battery Issues Report

Found this spot on for our type of issues.

 

Same guy, more info: https://www.reddit.com/r/rav4prime/c...rvations_when/

 

This is probably a thread that should be combined with this one so that the same information won't be "discovered again" and repeated. Just saying

https://www.clublexus.com/forums/nx-...r-choices.html



YMMV.

MidCow3

 

The good news is that the 2024 NX450h+ holds its value. Hyundai bought out the lease, and I am now leasing an Ioniq 5. I don't know that I will never have a battery issue again, but if I do, it won't be on a Lexus. From what I have read, Hyundai does better battery management, so I don't think I am going to have a problem.

After just over 24 hours we already have both my wife and I working with the car app, something Lexus could never do. We will have an adventure with an all electric vehicle but I think that will be fun also.

 

Enjoy your Ioniq!

 

Hm, ICCU issues seem to be the root cause, which are its version of BMS, including the traction battery.

We just get to choose which forums we complain in, I guess.

 

So we were on a river cruise in Europe over Christmas. Last time the car was run was December 16. We arrived home yesterday. Today I tried to start the car and no dice. Lots of dashboard lamps on, error messages like the parking brake and others. But no start. So I boosted it using my NOCO. Am beyond pissed. 20 days parked inside our insulated (not heated) garage. If we had driven to a parking garage or the like near the airport, I would have been boosting it in the sub-zero cold outdoors after an 8.5 hour flight. Note this is the 5th time it didn't start. I have had the original battery replaced by the dealership. This is a big deal, I can't rely on the car. To me it's a design flaw. Maybe a class action needs to be launched. Will be thinking really hard whether my next car will be a Lexus. Will certainly be a hybrid.

 

Yea, that really is not a good feeling. I've not been driving my NX much at all mainly due to the persistent "salt storms" we've been dealing with as this winter seeing so many days with snowfall, fortunately I have other options. In any case, just last night I had put my car back on the charger to maintain given its low usage lately and I downloaded my battery history while I was at it. For the last 3 weeks...

I realize the charging strategy/function is slightly different between 350 and 350h, but as I've said before both suffer from very lack lustre charging strategy and also likely are pretty similar while sitting. I recall some tend to blame parasitic draw but I still think that while there is always some especially on a car with telematics, its not the main issue here (the 450h+ is going to be outside this scope because its got its own unique situation). On these graphs that cover the last 3 weeks, some takeaways... Between Dec15 and Dec 23 I drove it to work 5 days, each trip about 30 min each way and since then its been sitting. These drives certainly added "some additional charge" but within a matter of hours sitting it was gone. It appears at best to be a modest surface charge remnant, the car really only wanted to maintain a very modest charge despite a high active voltage when the car was running, it was not anything that had significant impact to the SoC for the battery. When sitting from Dec 23 to Jan 4th the car gradually lost voltage but over many days the voltage decline basically flat lined, very little draw, still startable. It looks like it can go a long time, but (and a big one, I like big butts and cannot lie ) there has to be a reasonably good charge to start with and the battery has to be healthy enough (sitting long periods of time at very low charge isn't the way either I believe). You can see after a full external charge the voltage does slowly decline over several days (even when being driven) before it flattens out. Driving just doesn't seem to help much and while parasitic draw seems quite low, without a regular external charge these batteries are quietly checking out. Go many weeks or months without it, then add a lot of sitting time and time to start saying hello to my little friend the NOCO booster.