How is Lexus venting the current lead acid?

 

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.

 

I am seeing essentially the same thing with my two 450h+ models. The voltage in READY mode is consistently at 14.1 to 14.2v (and on rare occasion, I've seen 14.4v) but, as soon as I start to drive, it soon drops to 12.5 to 12.6v unless the resting SOC was lower than normal. Like WellsB, I have started doing a trickle charge on each battery more often than once monthly, like every ten days or so.

 

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 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.

 

All I can say is what a hassle. I wouldn't do it

Push button go. buy new battery in 4 years, Rinse repeat,

 

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?

 

Don't know if it's all cars. Mine lasted about a year before crapping out. Not impressed to say the least. Now I carry a portable battery booster and some booster cables at all times. Also trying to convince Lexus Canada to install the trickle charger port at their cost.

Bought a Lexus for that peace of mind but now I'm constantly worried about coming to a car with a dead battery.

 

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.

 

There doesn't seem to be a correlation between less use and this issue popping up. Read the thread and you will see this to be true.

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.

 

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.

 

More data and information to help you make up your mind

 

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.

 

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.

 

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.