Our Lexus will be 2 in February, and I thought we had escaped the dead battery gotcha with the car.
We were gone for just over 3 weeks, but left our 24 NX450h+ plugged in while we were gone. I thought plugging the car in would avoid this.
This has pretty much cinched it with my wife that we are going back to BMW for our next car.
The AAA guy Lexus sent was very uncertain about how to get the key cap off and did not know about the door lever below the handle. We was going to use a tool to force the door open while my wife was looking on the internet. As soon as she said "lever below the door handle," I remembered it was there. I KNOW these are not Lexus trained folks but this guy could have damaged the car trying to get into it without doing any further checking himself.

 

You have a 450h+. When you say "plugged in", did you mean you had a trickle charger on the 12 volt battery ? The 12 volt battery was the battery that needed to be "plugged-in", not the traction battery.

Sorry.


YMMV,
MidCow3


P.S. - BMWs are great cars, very sporty in acceleration and handling and have 4 year warranty; but are very, very expensive to repair and maintain especially when they get outside of 4 year warranty period

 

You should NEVER plug in the car while you are away. The car is at best to stay below 80% charge while you are not using it for weeks. If you are going away, having it trickle charged would be the best option. Or if you are concern that you are having it plugged in while you are out, fully charge it and then put away your keys far from the car. Plugging it in, in fact causes the car to use more juice to monitor the charging system while you are plugged in.

 

When you left it plugged in, you doomed the 12v battery.

I think you have one of the good cars. The fact that you haven't had a problem until now. I would purchase a new battery and keep this car, you are one of the lucky ones. Like lsft said above, never leave the HV Battery plugged in for an extended period of time for the reasons he stated.

Sorry this happened to you.

 

WOW the problem is with the 12 volt battery depleting . as stated in response #2. If leaving your NX sitting for a period of time , connect a trickle charger on the 12 volt battery.



Forum members need not to put out false information about leaving the PHEV plugged in. Come on guys, check your facts, DON"T PUT OUT RUMORS AS FACTS!!!

Leaving a plug-in hybrid (PHEV) plugged in too long is not harmful, as a sophisticated Battery Management System (BMS) inside the car prevents overcharging. Once the set charge limit is reached, the system disconnects the charging voltage, and the car will not draw more power unless the battery level drops, at which point it will engage a "maintenance charge". Leaving it plugged in after charging can even be beneficial as the BMS continues to manage the battery's temperature and may perform cell balancing.

YMMV,
MidCow3

 

All new Lexus vehicles come with free 4 year roadside assistance unlimited miles. Call Lexus for roadside service using the rooftop button - if your battery isn’t dead of course. Call their toll free number to get free assistance including 12 volt battery issues. The service person that arrives should’ve been trained by Lexus on all the details on how to get in and boost.

 

I think I'm as surprised by the lack of outrage over this issue as the issue itself. Someone with a 2 year old Lexus shouldn't be needing a jump or tow. We also shouldn't need a trickle charger on our $60,000 new car to take a vacation.
Hopefully Lexus both covered a new battery and provided you a hearty thank you for your patience.

 

well for sure it’s costing Lexus Toyota quite a few bucks for warranted battery replacements and service calls for dead batteries.

I’ll bet dollars to donuts the new Rav4’s will have same issue if they’ve got all the new ota tech that these Lexus vehicles have. It surely can be fixed with a more sophisticated ‘go to sleep’ algorithm for parasitic draw on the 12 volt and give permission to allow 12 volt to use traction battery to maintain its charge when car is dormant.

Has anyone heard of other brands having this issue with their hybrids? I’ve heard Kia Hyundai allow 12 volt to utilize traction battery to prevent it from dying.

 

I heard Hyundai uses traction battery if necessary. But they have a bunch of other issues anyway.

You should not need traction battery power to leave the car for few weeks. Some parasitic drain is in place if you need it. Like runaway ECU, or plugin charging algorithm like in this case, or whatever. Dipping into the traction battery just masks the problem.

 

Lexus roadside assistance sent the AAA battery truck. The guy was obviously not trained about Lexus at all.

 

Once the AAA mechanic got into the car he was able to jump start the battery and get us going, but yes, I agree this is ridiculous for any car, let alone a top-line model.

 

Has anyone heard of other brands having this issue with their hybrids? I’ve heard Kia Hyundai allow 12 volt to utilize traction battery to prevent it from dying.[/QUOTE]

Genesis GV60 do exactly that. There is even a big orange led on top on the dashboard that lights up when that is happening.
EVs dont have an alternator to charge the 12V battery and with a dead battery, it cannot start and be driven.

 

Toyota / Lexus regular hybrids and plug in's don't have a regular alternator either. They use the ICE engine and regenerative braking to provide charging of the the traction battery and the 12 volt which receives it's power from the Inverter which steps down the 280 volt to 12 volt. Only the ICE gas 250 and 350 have an alternator.

 

Anyone know if the BMW i4 has this problem? This is what I am looking at to solve the problem.

 

Just Google search it. Looks like there are owners who have problems with 12V with the I4 as well.