Folks;

For all you owners out there, a word of caution. Right now I'm wating for a boost. Was waiting on the Wife to get into the car and playing around with some settings. I managed to kill the 12V battery! Honestly didn't think it was that long, maybe 10 minutes, but I drained it enough to render the car dead. Needed to use the backup method of exiting the vehicle.

 

You too!. I have same car, '22 350h Executive. Live in Niagara region. I spent about 20 minutes one evening, shortly after picking up the car back in November 2022, putting in a rear seat cover used for dogs. Just had car unlocked, turned off interior lights too. When I was done, went to start it up to reverse it back into my garage and it was DEAD. I even tried using the Lexus Safety Connect button located up on roof panel by interior lights and it wouldn't function! Thought I would contact them for a boost seeing as it was as new as they come and didn't want to mess anything up. Everyone who owns any model of NX of this current generation should be aware that most likely Lexus has scrimped on battery size as much as possible, probably to reduce weight and space at the expense of safety as far as I'm concerned. I had earlier that day driven a good 50 kms, so you think battery state of charge would have been topped up. Did some investigating, and there are other threads on the site as well with similar stories as yours too. I've commented on them as well. Took some readings of my battery and found it very low, around 11.5 volts which is harmful for battery life. I've bought a Nico Boost GBX45 and keep it in car so I'm prepared for another occurrence. Thinking on installing a trickle charger soon too. It looks like battery has a lot of parasitic draw on it while car is off and parked. Which slowly drains it. If you're not driving it every couple of days for a 40+ kms I would consider having yourself equipped with something similar as I've done. I've adopted a new habit of keeping the darn car started and ON if I'm going to be, as you did, sitting for a while in it, waiting for someone to finish their business and return to car to carry on.
As soon as battery is showing signs of failure I'll be switching to an AGM type battery with a higher cold cranking amp rating that will still fit in vehicle. An FYI for Canadian readers, I've used CanadianTire's Eliminator AGM batteries in both my other vehicles over the years and they last easily 7 years, which is well beyond 5 year warranty period, without any issues. Highly recommend them. The replacement for the 350h is rated at 600 Cold Cranking Amps, the OE from Lexus is only 563 CCA.

 

Highly suggest keeping the car running and use the traction battery if you are waiting. Make sure the READY light is lite and since the gas engine doesn't start unless you are extremely low on the hybrid battery it's better that way. Also, while you are on READY, it will also charge the 12V battery while you are idle as well.

 

Yup, just keep the car in Ready mode when playing. I traded my RX hybrid still with the original12V battery, 14 yrs old, still worked fine and never once let me down. In ready mode, even if the engine is not running the 12V system is fully energized and battery chg will be maintained.

 

The RX Hybrid has less always running features. The mobile app works, because the 12V battery is used when you check status and stuff form your phone. If you have digital key, the car also has the bluetooth running so that it can connect with your phone. Lots of things that are running and if you have a dashcam in parking mode that also pulls. My NX had no problems with the 12V until it got very cold and then it died. It seem like it was able to maintain 50% most of the time. So now from time to time (2-3 weeks) I do a 12V charge while charging my 450h+. The 450h+ is worst cos while the car is not charging and you have the car plugged it, the system is awake to monitor the temperature and stuff causing more drain.

 

Sucks to be you I guess. Just kidding. Still a bit envious as a long time hybrid fan/driver and would have loved to get a 450h+, but just didn't want to wait. Could barely wait the 5 weeks to get my turbo

 

Live in Niagara region.

Hi Neighbour! We're in Welland!

 

Hi Back JasDmw! I'm here in 'The Falls'. Excellent choice for your Lexus! I've got a 22 NX350h Executive with Eminent White Pearl over Palomino. You purchase yours from Performance Lexus?

 

In my opinion this is one of the big problem with the new generation NX. A lot of things run off the 12V battery including the electric doors that will quickly drain the battery if opened few times without starting the car. Hopefuly Lexus will recognize this at some point and provide a fix.

 

I think it was the big screen that sucked the most power out of the battery.

 

18 months with our 2022 NX 350h and no battery issues.

I will sit and listen to the radio waiting for my wife 😊 shopping. Sometimes with the car “Ready” for hvac and sometimes not.

I would like to add that my 2016 and 2018 ES350s had bad batteries. 2016 was replaced by the dealer and the 2018 I bought an Interstate AGM battery and called it a day.

Has the battery been tested?

 

I'm about to install a dashcam and which will have parking mode. I wonder if my dash cam would be capable of killing the battery. With WFH, there can be 2-3 days where I won't drive the car too.

 

We have a BlackVue Dashcam.

There is a Voltage monitor that will shut it off if the battery reaches a certain level when it is in park mode.

With that said it will stay on for sometime but I have noticed if we are opening/closing the rear power hatch several times while shopping it will shut down the camera.

BlackVue, I assume others, offer an auxiliary power pack.

 

I saw a video today from a Japanese owner of NX350h saying he had dead batteries and the NX has a battery draining problem/bug. Reading through comments it appears to be not uncommon. I’m guessing that is what you are also experiencing.


*edit: Just did some Google search on this issue, turns out it is wide spread and has been around for years. What Lexus doing that it’s still happening in 2023????

 

Where did you get this information?

When I have the computer connected to the "HV Battery" ECU while monitoring a charge, communication is lost a few seconds after the charging session finishes. All the battery temperatures come from the HV Battery ECU.

I suppose the "Plug-in Control" ECU (or maybe something else) could stay awake; but, if the HV Battery contactors are open (the HV battery is internally disconnected when not charging/discharging) and the EVSE shuts off, what would need to be monitored? The Plug-in Control does monitor the temperature of the + and - charge port terminals and the DC/DC converter; but again, if those are fine before everything shuts off, they will be fine after.

I could maybe look into it at some point; but, I don't often charge to full... and if I don't know what I'm looking for it may take a while to prove/disprove.