450H 12v battery issues
Thread Starter
10th Gear
Joined: Feb 2017
Posts: 13
Likes: 4
From: TX
450H 12v battery issues
Anyone else having issues of total 12v power loss on PHEV? Happened twice, first time dealer tested and recharged and fixed for a couple of days. Now waiting on new battery (very rare).
Could it be using just EV most of the time or accessing to car online too often on multiple devices or what?
Could it be using just EV most of the time or accessing to car online too often on multiple devices or what?
Driver
Joined: May 2022
Posts: 62
Likes: 16
From: CA
I've been using EV mode for about 90% of my commute (commute is too long to make it the whole way on just EV) and check the status of my car on the app ~5 times a day and I haven't had any issues. The car is designed to be used this way. It also reserves roughly 20-30% of battery for HV mode and doesn't let you get all the way to 0% charge even if you wanted to. Even if you were hitting your battery hard, it's only been out for a few months so unless you've been jumping cars every day (which you shouldn't be doing with a hybrid) regular use wouldn't be enough to kill the battery. Sounds like you just got a faulty battery or maybe power control in your car is off.
Driver
Joined: May 2022
Posts: 62
Likes: 16
From: CA
sorry the way I phrased that might've been a little confusing. What I meant was that it's most likely the battery but if not then might need to check how the car is controlling power draw from the battery. The computer should be monitoring how much charge is left in the battery and stop drawing power before it hits 0% but if it's not then that could also potentially be causing your dead battery experiences. But most likely it sounds like it's a problem with the battery.
Intermediate
Joined: May 2016
Posts: 353
Likes: 173
From: CA
Anyone else having issues of total 12v power loss on PHEV? Happened twice, first time dealer tested and recharged and fixed for a couple of days. Now waiting on new battery (very rare).
Could it be using just EV most of the time or accessing to car online too often on multiple devices or what?
Could it be using just EV most of the time or accessing to car online too often on multiple devices or what?
I hard wired a quick connect cable to the battery that just reaches the end of the trunk mat, and I mounted the tender on the wall near a plug, so it only takes a few seconds to connect it.
Here's the one I use, nice and compact. I had an older model that worked well for years:
And here's the connector (used to come standard):
Last edited by ct6978; Jun 24, 2022 at 04:27 PM.
Trending Topics
ClubLexus Stories
Celebrating Lexus & Toyota from Around the Globe
Lexus NX 350h: A Fuel-Sipping Secret Hot Hatch???
Michael S. Palmer
5 Best & 5 Worst Lexus Daily Drivers
Joe Kucinski
Top 5 Hottest Lexus & Toyotas in 2026 (Hardest To Buy)
Brett Foote
2026 Lexus IS 350 F Sport Review: The Last of Its Kind Still Rocks
Michael S. Palmer
Top 10 Most Confusing Things Lexus Has Ever Done!
Joe Kucinski
2026 Lexus ES Review: Lexus Re-Embraces Founding Principles
Michael S. Palmer
10 Lexus Bargains That are Cheaper Than a New Toyota RAV4
Joe Kucinski
8 Weirdest Things Lexus Has Ever Built
Verdad Gallardo
10 Lexus Designs That Have Aged Like Fine Wine
Verdad Gallardo
Driver
Joined: Jan 2022
Posts: 73
Likes: 19
From: CA
I've been occasionally (aiming for weekly) hooking up a battery tender to the 12V, even it gets driven daily by my wife. I'm surprised how much time it takes to get to trickle mode vs. my car (ICE) that I rarely drive, so I connect a tender each time I get back in the garage. The NX does have a power rear door that gets used often, but I would expect the 12V to get topped off in either ICE or EV mode.
I hard wired a quick connect cable to the battery that just reaches the end of the trunk mat, and I mounted the tender on the wall near a plug, so it only takes a few seconds to connect it.
Here's the one I use, nice and compact. I had an older model that worked well for years:
https://www.amazon.com/gp/product/B07W8KJH44
And here's the connector (used to come standard):
https://www.amazon.com/gp/product/B004LWWNLC
I hard wired a quick connect cable to the battery that just reaches the end of the trunk mat, and I mounted the tender on the wall near a plug, so it only takes a few seconds to connect it.
Here's the one I use, nice and compact. I had an older model that worked well for years:
https://www.amazon.com/gp/product/B07W8KJH44
And here's the connector (used to come standard):
https://www.amazon.com/gp/product/B004LWWNLC
I also have a dash cam with parking mode but the battery never has enough charge to keep it on even though I drive it daily. So I’m thinking I need to add a charger for the 12v daily too but I would like it to be super convenient like you describe. Thanks
Intermediate
Joined: May 2016
Posts: 353
Likes: 173
From: CA
I’m interested in your charging setup…can you post a picture of the quick connection connected to the tender? Why don’t you just connect the tender to the connections under the hood?
I also have a dash cam with parking mode but the battery never has enough charge to keep it on even though I drive it daily. So I’m thinking I need to add a charger for the 12v daily too but I would like it to be super convenient like you describe. Thanks
I also have a dash cam with parking mode but the battery never has enough charge to keep it on even though I drive it daily. So I’m thinking I need to add a charger for the 12v daily too but I would like it to be super convenient like you describe. Thanks
Here's the photos, the connection point is tucked under the trunk mat edge when not in use, the rear door closes fine over the cable when in use. I have a tender wall mounted on each side of the garage, very convenient. I haven't been driving my car (front battery, so I pop the hood) too much recently, so it usually stays hooked up...the NX is my wife's car and I usually change it weekly.
Driver
Joined: Jan 2022
Posts: 73
Likes: 19
From: CA
I think I decided the trunk approach would be neater based on where the charge points were in the engine bay....I'll relook at it again.
Here's the photos, the connection point is tucked under the trunk mat edge when not in use, the rear door closes fine over the cable when in use. I have a tender wall mounted on each side of the garage, very convenient. I haven't been driving my car (front battery, so I pop the hood) too much recently, so it usually stays hooked up...the NX is my wife's car and I usually change it weekly.
Here's the photos, the connection point is tucked under the trunk mat edge when not in use, the rear door closes fine over the cable when in use. I have a tender wall mounted on each side of the garage, very convenient. I haven't been driving my car (front battery, so I pop the hood) too much recently, so it usually stays hooked up...the NX is my wife's car and I usually change it weekly.
Intermediate
Joined: May 2016
Posts: 353
Likes: 173
From: CA
Racer
Joined: Apr 2015
Posts: 1,727
Likes: 814
From: Ontario
I drained my battery down to 10.4V this morning and tested by starting the vehicle and it charged back. The headlights seem to drain the battery very fast. Started the car and waited. I see the car is charging the battery with 13.x volts.
It does seem that if you are driving, the battery stays around 11.8 to 12V. It could mean that driving doesn't really charge the battery that fast.
After 14 mins I did see the battery gets back to 11.8V.
It does seem that if you are driving, the battery stays around 11.8 to 12V. It could mean that driving doesn't really charge the battery that fast.
After 14 mins I did see the battery gets back to 11.8V.
Intermediate
Joined: May 2016
Posts: 353
Likes: 173
From: CA
I drained my battery down to 10.4V this morning and tested by starting the vehicle and it charged back. The headlights seem to drain the battery very fast. Started the car and waited. I see the car is charging the battery with 13.x volts.
It does seem that if you are driving, the battery stays around 11.8 to 12V. It could mean that driving doesn't really charge the battery that fast.
After 14 mins I did see the battery gets back to 11.8V.
It does seem that if you are driving, the battery stays around 11.8 to 12V. It could mean that driving doesn't really charge the battery that fast.
After 14 mins I did see the battery gets back to 11.8V.
