Is there a recommended charging strategy for the RX 450H+ and other plug in hybrids.
I tend to run short errands and was plugging it in when at home. The engine has not run in 6 weeks.

This last charge, I exhausted the EV range and then plugged it in.
Is there a charging strategy that is recommended for optimal battery health?

- Rich

 

I'll preface the following with the statement that Lexus has a 10 year 150k miles warranty on the traction battery and I am confident it will last at least that long in normal use.

It is commonly accepted that lithium batteries have the longest life span when kept between 40 and 60% of capacity. The RX450h+ shows a full charge at around 90% and zero miles EV range at around 12%. You can divide your max EV range by 2 to get your roughly 50% mark.

Personally, I target 60% for charging if the vehicle isn't going to be driven for a while. That leaves it with plenty of range for unexpected trips or the random 2-mile grocery run. If I know it's going to be driven further, I set the schedule for it to be fully charged at the beginning of the trip. During road-trips where I'm not charging the traction battery, I attempt to keep the battery around 60% using HV and Charge mode when necessary.

My reasoning is that, even though there is a warranty, the battery will still degrade faster if I leave it fully charged or discharged all the time, and that will mean a loss of range over time. It's worth my time to slow that degradation and loss of range down. So far, in 25k miles with about 1/4 of that being EV, I can detect no loss of range.

 

And how is it that your 12v battery hasn’t completely drained. (I ask with incredible curiosity). I purchased a 2025 450h+ three weeks ago and have had to charge the 12v battery 3 times with a trickle charger. Based on other threads, I purchased and installed a battery monitor. The voltage drops to under 12.1v in 5 days. The SOC goes from 100% to 30% in the same timeframe. I took it to the dealer and have been told to: drive 30-40 mile trips 3 times a week to charge the 12v battery. Even with a 40 mile trip, there is a net loss of voltage.

while this reply might not be exactly on topic, I will respond that when I use all the hybrid battery I charge it. So 1/2 discharge, wait. Full discharge, plug it in.

I am getting 38-43 miles pure electric range.

 

I get about 40 miles per charge now that it is spring in New England.
In wider, 30 is a stretch.

My 2025 450H+ is garaged, I don't know if that matters. The phone based key is not installed, I don't use ACC mode, and the iPhone background refresh is off for the Lexus app.
Other than that, I have no idea why it is not giving me any trouble.

- Rich

 

You got a good one that’s for sure. I also garage mine, do not use a phone key, do not use ACC, and do not have the Lexus app installed.

Glenn

Here is the SOC for the past few days


From ANCEL bm200

 

That does not look good. Could the monitor be impacting it?

I also drive at least every 2 days, mostly short trips. I do not intentionally leave it plugged into the charger, but occasionally overnight.
Recently, I went away for 8 days with the car unplugged with no issues.

I don't think the Lexus App is a drain, and it permits you to remote start which is in EV mode, that is reported to charge. That would be interesting.'
It might be worth a try, maybe it keeps doing something dumb when it can't communicate with the App.

- Rich

 

Couple of additional good points that you mention. I also do not leave the car plugged into the charger. (I had read that might cause some drain issues).

Kind of a chicken and egg situation with a monitor.if I don’t have it, then how do I know about the drain. Letting the battery die doesn’t seem very viable. I guess I could go out every few days and test with a voltmeter, All part of the troubleshooting process I guess. I’ll give the Lexus app a try also. I sure would like to enjoy the car instead of worrying about the battery dying at the wrong time.

thanks for the feedback and tip(s)

Glenn

 

The monitor has very little impact compared to the vehicle parasitic draw. I have bluetooth monitors on all of my cars now and the RX is the only one that discharges so quickly. My '07 Focus took a month to drop from 12.59 to 12.29. That's with a battery that is 5 years and 7 months old.