Dead 12v battery Incident (merged threads)
#421
I was initially settling on the AGM Walmart sells, because its cheap at $180 and also has 4 year replacement warranty serviceable at any Walmart. However, on looking closer I found that it has two "venting" ports that can release occasional gas from the chemistry - which makes that particular AGM a problem for the NX/RX batteries that are sitting in the passenger cabin. However, the Odyssey AGMs are fully sealed and do not have those vents.
#422
I simply can't imagine being able to notice a fuel economy hit from using an AGM battery. We're talking miniscule power requirements, in comparison to actually moving the vehicle.
Just to be clear, Odyssey documents talk about recovery from deep discharge sometimes requiring much higher amperages than regular chargers can supply, combined with a requirement that voltage not go too high while providing those amperages. There is a very short list of chargers that can do that.
It has a vent hose to the exterior.
Just to be clear, Odyssey documents talk about recovery from deep discharge sometimes requiring much higher amperages than regular chargers can supply, combined with a requirement that voltage not go too high while providing those amperages. There is a very short list of chargers that can do that.
It has a vent hose to the exterior.
Last edited by WellsB; 06-08-24 at 11:27 AM.
The following users liked this post:
Urlik (06-08-24)
#423
My observations of the charging behavior of the RX450h+ lead me to believe that it is time-based. It seems to have no concern for battery charge state. There is an initial 14v charging cycle while driving, but then it drops to a low float-voltage, around 12.8, at most times. The primary exception is when the vehicle is in Ready mode and in park. At that time, the voltage stays above 14.
I did observe the charging system stay above 14 volts for about 30 minutes, while driving. I believe this is a time-based maintenance cycle. In 3 weeks of driving, I've only seen it happen once. The battery was not at a low state of charge when it occurred.
I did observe the charging system stay above 14 volts for about 30 minutes, while driving. I believe this is a time-based maintenance cycle. In 3 weeks of driving, I've only seen it happen once. The battery was not at a low state of charge when it occurred.
Last edited by StefanoS; 06-09-24 at 09:03 AM.
#424
I have been reading this thread over 2 days already (long thread). Lots of great ideas and info. Appreciate all the effort in solving the issue.
Has anything from Lexus or dealer tech mentioned anything on a solution?
I have trickle charge my NX once it's getting lower 12V lately also before reading this thread.
Today I did a test and it showed around 12.02 V and drove it for a few minutes today and measured the voltage back to 12.5V.
Has anything from Lexus or dealer tech mentioned anything on a solution?
I have trickle charge my NX once it's getting lower 12V lately also before reading this thread.
Today I did a test and it showed around 12.02 V and drove it for a few minutes today and measured the voltage back to 12.5V.
The following users liked this post:
Ganoush (06-09-24)
#425
Has anyone measured their voltage in accessory mode prior to starting the car (after sitting all night)? I charged my 350h about 2-3 weeks ago. It measures 11.8v prior to starting. Then goes up above 14v once the car starts and then 12-13v while driving. Is 11.8v or lower considered ok or should it be replaced? I never had any issues starting the car and is about 1.25 years old. I plan to charge it every 1-2 months. I think I would have serious reservations buying a 450h+ knowing how much more of an issue its battery problems are compared to the other models. It amazes me how Lexus is so complacent fixing this given how long the NX450h+ has been out and having similar problems.
The following users liked this post:
neilsarkar (06-10-24)
#427
Can anyone who has been following more closely summarize this thread so far? Would like to catch up as a potential 350h buyer since this seems to be a pretty serious problem but I don't have a full day to read all 250 comments.
A lot of discussion about trickle charging as a solution, is this really what I am committing to if I buy this car...? I have to constantly babysit the battery every week?
A lot of discussion about trickle charging as a solution, is this really what I am committing to if I buy this car...? I have to constantly babysit the battery every week?
The following users liked this post:
SolidG1 (06-09-24)
#428
Can anyone who has been following more closely summarize this thread so far? Would like to catch up as a potential 350h buyer since this seems to be a pretty serious problem but I don't have a full day to read all 250 comments.
A lot of discussion about trickle charging as a solution, is this really what I am committing to if I buy this car...? I have to constantly babysit the battery every week?
A lot of discussion about trickle charging as a solution, is this really what I am committing to if I buy this car...? I have to constantly babysit the battery every week?
Bought a Lexus for that peace of mind but now I'm constantly worried about coming to a car with a dead battery.
#429
Ganoush,
I have had my 350h for 1 &1/4 years and so far have not been stranded or had any dead battery problems. I think this problem is much more prevalent on the 450h+ Because of this forum, I just started charging every 1-2 months and carry a portable charger which has not been needed. I think if you use you vehicle daily or a few times a week and you trips are not just around the corner, you would be fine. If the car sits for 1-2 weeks and only goes short distances, then you might need to charge it some.
I have had my 350h for 1 &1/4 years and so far have not been stranded or had any dead battery problems. I think this problem is much more prevalent on the 450h+ Because of this forum, I just started charging every 1-2 months and carry a portable charger which has not been needed. I think if you use you vehicle daily or a few times a week and you trips are not just around the corner, you would be fine. If the car sits for 1-2 weeks and only goes short distances, then you might need to charge it some.
#430
Ganoush,
I have had my 350h for 1 &1/4 years and so far have not been stranded or had any dead battery problems. I think this problem is much more prevalent on the 450h+ Because of this forum, I just started charging every 1-2 months and carry a portable charger which has not been needed. I think if you use you vehicle daily or a few times a week and you trips are not just around the corner, you would be fine. If the car sits for 1-2 weeks and only goes short distances, then you might need to charge it some.
I have had my 350h for 1 &1/4 years and so far have not been stranded or had any dead battery problems. I think this problem is much more prevalent on the 450h+ Because of this forum, I just started charging every 1-2 months and carry a portable charger which has not been needed. I think if you use you vehicle daily or a few times a week and you trips are not just around the corner, you would be fine. If the car sits for 1-2 weeks and only goes short distances, then you might need to charge it some.
On my 350h it is used almost every day for at least 100km/day. In fact when my battery died it was driven the day before, went to start it up in the morning and it was dead. Had to manually open the door with the physical key.
#431
Overburn, I was commenting on my car experience. Also since the 12 volt will only charge when the car is turned on, the more it just sits, the less time the traction battery has to charge it. Lots of other facts can effect battery performance. (temperature out side, accessory mode use etc.) Lexus definitely has a battery issue most commonly on the 450h+ and to a lesser extent in its other models. Watch the video below, he talks about short trips and the effect on battery performance.
The following users liked this post:
CCGS (06-10-24)
#432
The following users liked this post:
GHN1013 (06-09-24)
#433
Yeah, I've seen ours drop to 11.8 right after hitting the start button. Accessory mode will rapidly pull it below that.
For comparison, my Ford Focus pulls the voltage down to around 10.8 volts when engaging the starter.
For comparison, my Ford Focus pulls the voltage down to around 10.8 volts when engaging the starter.
#434
Is the stock Panasonic battery that comes with the 450H+ any way different from a run-of-the-mill flooded Lead-Acid battery in terms of deep-discharge voltages it can sustain without damage ? Did Lexus source it from Panasonic with the particular risk of deep discharge in mind for these new RX/NX models?
I'm trying to decide if I should even ask for a new battery if the dealer finds it to be only slightly or not degraded at my 6 month service. The reason being, the run-of-the-mill Interstate 12 V that the dealer would replace it may actually be worse for the Lexus, given its deficient 12 V charging problem. There are at least anecdotal reports of folks having battery deaths even with new battery replacements - presumably due to their parasitic drain being high. In my specific case, I don't think my parasitic drain is very high (since it survived a 26 day parking without problem) - just the overall deficient charging design is the problem.
I'm trying to decide if I should even ask for a new battery if the dealer finds it to be only slightly or not degraded at my 6 month service. The reason being, the run-of-the-mill Interstate 12 V that the dealer would replace it may actually be worse for the Lexus, given its deficient 12 V charging problem. There are at least anecdotal reports of folks having battery deaths even with new battery replacements - presumably due to their parasitic drain being high. In my specific case, I don't think my parasitic drain is very high (since it survived a 26 day parking without problem) - just the overall deficient charging design is the problem.
#435
It's quite possible that the OEM battery is a deep cycle battery, considering that most batteries of similar size have 600-700 cca, vs the 345 cca claimed for the OEM battery.
Mine has been deeply discharged twice, and still shows very little wear on the tester.
Mine has been deeply discharged twice, and still shows very little wear on the tester.
The following users liked this post:
wrinkle (06-10-24)