ag97690

I was gone for 10 days and the 12 volt battery was dead too. Wonder what is causing a drain on the engine starting battery that it wouldn't last more than a week. I know I go a long time on the electric engine only , but I thought they would have some type of built in trickle charger to keep the other battery charged up. Guess I was wrong on that assumption.

LexES300h

I picked up my car on a Saturday, and the 12 v battery was drained by Monday.
I had to get a jump from AAA. I am so freaked out. How can a brand new car battery be discharged so quickly?
I will take the car back to the dealer to get it checked.

The car horn/alarm kept going on every 20 minutes at work. I read somewhere that this might be due to the low charge battery. Which is dumb, the battery is low, and you start using power to honk the horn?

genadi

I have a two months old 450h and battery discharged twice already when I have not used the car for more than three days. I was able to boost the car, it is pretty easy with a portable booster battery, they are widely available on Amazon, Costco etc. All it takes 5 minutes.
Something like this one, very handy to keep in your car. Be careful not to put it under the trunk cover, when battery is dead you will have a problem opening the trunk,

https://www.costco.ca/shell-sh912-ju...100799481.html

I am planning to take the car to the dealer to check for parasitic power draw.

Also, someone told me that his Lexus RX350 had the same issue. Apparently, the car has some sort of standby or sleep mode and, that was the problem with his car. He went to the dealer and that option was turned off, he never had it again.

lsft

Keep in mind that your new car communicates to your mobile app. Do you check the status of your car frequently? Also, do you have digital key setup? If your phone is close by to your car, it will continuously ping your car and keep it connecting. Also, when you drive your vehicle, do you drive very short distances?

Datanator

interesting theory, but the counterpoint to this is if this car is so prone to battery drainage due to proximity of the phone to the car or the number of times the owner checks status from the app, we’ve got some bad design here. The car should know when things are draining to the point where it becomes an issue and block access to the phone or the app. the software should be smart enough to determine the trend. The owner of this model should not have to worry about number of times checking the app or how close the phone is to the car. Again, if this is truly the issue, there’s some serious design flaw going on here.

Kusala

Also on Tesla's and is not limited to Lexus or any other car. It's called vampire drain.

I've never had this problem with my 450h after months of ownership.

genadi

With all this kept in mind, all these must not drain the battery. Otherwise, buying a lux vehicle and thinking about tech details defeat the purpose of owning one.
My second vehicle is 2018 Chevy Volt, also with connected services like app, smart locks etc… may be fewer features but, smaller battery and similar to Lexus phev design. It has never had drained battery in almost five years of ownership. Although, statistically now, it’s time to look into getting new battery on it…

Kusala

The number of computers between a five year old car and present day are massive. Five years is a technological eon.

What @lsft posted is not a theory it is factual.

genadi

so, what you are saying, draining a battery to zero in three days of not driving is normal

scooky

I accept all of the above as valid at the same time.
Yes vehicles have more going on than ever before. There are new demands and stresses.
I also expect better. These new demands seem pretty obvious. I would like to see the engineers find good solutions.

I still very much like this vehicle and will for a long time.
I do wish ownership was a little more seamless and didn't have to dance around some of these issues.
Some will get better with time though.

lsft

Well, I've own this car for almost 6 months and I never had a 12V drain. In fact, my CT has drained more cos I don't drive that car as often. I even used the 450h+ to boost the CT once as I didn't have the portable booster. One thing I do often do is have the car on for many minutes because of myself recording youtube videos and in fact it does recharge the 12V battery. I have tested this when I was recording the personalization video where I didn't power on the car and used the obd2 plug. About 20 mins, it started to say that my 12V battery is low. I had to power on the car and let it run for 15 mins to charge it back up.

I actually spoke with my wife on this issue. Lexus should have a system that pings the vehicle every hour or two and check the battery level of the 12V. Since it can do remote start, it should automatically start the vehicle and let it idle to recharge the 12V. Once completed, it will power it off.

Or just advise us the battery is low and you should start it to recharge. Instead of telling me that I have something in my back seat, this would be a great feature to have.

Kusala

No. I am suggesting it is likely operator error or there is something going on with your vehicle. Battery drainage is known across various platforms. That's not to say that there isn't room for improvement.

scooky

12v discharge isn't a new thing. I have an older truck and motorcycle that need to be battery tendered during the off seasons to avoid discharge. This is normal for vehicles that don't move for months.
Above stories sound more like days to weeks though. That seems awful fast. I'm curious what the root cause of that is. Sitting for at least 2 weeks seems like a reasonable expectation to me.

@lsft Appreciate all the great vids you've made.
Like the ideas.

mbezzo

450h+ here with 6100 miles of mostly-EV driving and we've yet to have any 12v issues. 3-4 days is probably the longest it has sat without being driven though, and most of our trips would be in the longer than 15 minute range. Just to add another datapoint to the pile...

lsft

Your 15 minute drive will charge the battery up. Do you have the digital key?