KrzysiekKTA

Good Day,

I have completed over 3k miles road trip from Houston to Colorado and back (with some significant winter mountain driving - all the way on 19" X-Ice snow tires) and have very similar fuel economy experience - 37.9/33.8 mpg (HV+EV / HV only).
Couple of notes from my experience in mountain/cold driving:
1. EV-Auto drive mode is almost completely useless unless going up and down the step hills at less than 60mph - manual HV/EV switching works way better to take advantage of superb EV efficiency below 50-55 mph.
2. RX refuses to continuously use EV in temperatures below 10degF - it engages ICE often to keep with cabin heating demand (I guess)
3. Charge Mode - only useful on long smooth downhill stretches to build any EV charge to prepare for steep downhill grades
4. Steering gear shifting paddles to control regen in EV mode - not practical for that purpose - modulating regen with brake pedal works better.
5. Tried "EV-banking" (I am ex. Prius Prime driver) to charge up the traction battery by regen and it works, but with much less benefits than in my old Prius Prime.
6. I really wish the EV-Auto could be configurable as OP mentioned or at least the EV/HV switch located on steering wheel or even better its function assigned to Steering wheel paddles

As a road-trip car RX is really good choice - even at 80mph cruise controlled speed on flat roads the MPG does not drop below 30 mpg - yet I have experienced 25mpg climbing up to Great Plains from sea level.

Just my 5 cents.

Brgds

K

wrinkle

Thanks for sharing all the "experiments" data that you are gathering.

For me, I think the fuel economy and EV mode that really matters is my daily 17-mile-each-way work commute - I haven't done any long road-trips. My commute is where I spend/pollute with gas for 90+% of my annual driving - and wanted to remedy with the PHEV. In that, I'm totally averaging about 45.5 mpg and 2.5 miles/kwh in EV, having about 35 miles of EV range for mostly-highway-heavy-traffic Bay Area commute, and so far with my odometer at ~575 miles. And charging at work is free, but finding open slots is competitive (with Tesla drives who can't get home without charging!), so will see what happens with the gas cost savings as I try to avoid charging at home, given my sky-high PGE kwh rates

The road-trips are few and far between for me, so even a much worse mpg than above wouldn't really matter to me in the grand scheme of things. That said, a comfy and reliable road-trip vehicle was a must for me, which seems to certified by you folks above.

Probably the most important feature I'm most appreciating daily are the ADAS features in heavy Bay Area highway traffic - very well-executed by Lexus - accurate, non-intrusive for the most part and doesn't "give up" on slightest lane making problem. I have been in a 2023 Tesla Model Y - and everytime there is a slightest curve in the highway, it would disengage. Lexus executed the ADAS very well, which is rare in the industry (I had tried it in a 2019 Audi Q7 loaner as well, and it was awful - not sure how the latest one is - but Consumer Reports rated Lexus as the best of breed in effectiveness, along with Mercedes, in ADAS and that seems right). And should also mention how much I'm loving the "quiet" EV ride, something you can't quantify with a monetary benefit.

WellsB

I have taken to using Auto EV-HV in place of EV mode. I had a moment in EV mode where I misjudged the speed of an oncoming car and was almost hit, because I did not have full-power available. The oncoming car was driving way over the speed limit. With Auto EV-HV mode, full power is always available if needed, and does not engage the ICE except at near full-throttle.

I strove to keep the traction battery between 50 and 70% state of charge during the trip, with 65% being my ideal target. I use Dr Prius app to see the true state of charge. 65% is about ideal for battery longevity and is what I charge to when the car will not be driven for a while.

I used Charge Mode extensively to bring the SoC to 75% (the highest the system charges to in Charge Mode) before entering cities. I just prefer to use EV in city driving. I found that around 5 minutes of driving at highway speeds would charge the battery 1%, though regen usage in charge mode would top it off much quicker..

I also found that the brake-pedal is better for using regen in EV mode. The paddles will engage engine-braking, which reduces the regen. The brake pedal will too but doesn't seem to do it as quickly.

I found that regen amperage is limited after a certain period of time has passed. This only occurs on long steep downhill grades. Regen would exceed 100 amps for some period of time, then engine braking would engage and Regen would be limited to around 40 amps for the rest of the grade. I believe this is to protect the battery.

As mentioned above, I never experienced temperatures below 19 degF, and at that temperature, the heat-pump worked fine and would bring the interior up to a comfortable temperature using remote start. We used remote start on every cold morning and would then use charge mode to recharge the battery. The engine never fired up unless front defrost was turned on, which is normal behavior. My understanding is that the heat-pump is ineffective at lower temperatures, so that the engine will be started if heat is required. I imagine that battery protection comes into play as well, at very low temperatures.

I used no extreme hypermiling techniques. I just drove the speed limit and did my best to coast to 10 mph before engaging braking, and generally kept acceleration on the line between ECO and Power, except when more power was required for safety.

As a comparison, our 2013 RX350 averaged about 23 mpg over it's lifetime and 24-25 mpg was its road-trip average. The best fuel economy we ever saw was 27 mpg with that vehicle with city traffic taking it quickly below 20 mpg.

StefanoS

Once again, this is good info and many thanks for your continuing input. I'm more than a little disappointed with the paddles and the engine braking. To me, it almost seems a little unnecessary and I cannot imagine using it very often, if ever. I would have preferred using these to set the level of regeneration, rather than engine braking. One of my brothers, in the Midwest, has an Ionic 5 and he tells me that he is able to adjust the level of regeneration.

StefanoS

As an addendum to the above, my brother tells me that he rarely has to use the brake pedal in his Ionic 5 while driving, as the regen slows the car just fine.

WellsB

I do wish the regen was adjustable and that the paddles were more effective for regen. It is more aggressive in sport mode.

StefanoS

Thanks for that.......I had not really given sport mode a shot yet but, I will now.

WellsB

I just checked and regen at 65 mph in Normal mode starts at around 40 amps of regen, while sport mode starts at around 80 amps.

StefanoS

Good to know, thanks.

KrzysiekKTA

Actually that is a very valid point to use EV-Auto instead of EV mode. It has happened to me once that I lacked the full power to complete the overtaking maneuver in decent time.
As EV stays exclusively on up to 84mph that might be a safety recommendation to use EV-Auto instead of EV-mode.

Many Thanks

K

wrinkle

Dumb question - how do you make Auto-EV the default startup mode - so that every start-up happens with Auto-EV-HV all the time as default ? This is good advise, I'd also like to be in Auto-EV-HV but the car starts up by default in EV (I tried a long-press of the Auto-HV-EV but it doesn't do the trick). Thx.

KrzysiekKTA

As far as I know neither every Toyota/Lexus Plug-in defaults to EV mode - EV-Auto can be activated manually only. Maybe the Dealership can use Techstream and program the logic to default to EV-Auto, but I doubt it.
Will ask at my next visit when picking up second remote and programming rear hatch lock button.

Brgds

K

WellsB

On mixed 75 and 80 mph interstate runs, our RX450h+ gets around 28 mpg. Fuel economy increases quickly as speeds are reduced. Lifetime is 35 mpg if accounting for EV usage over 7,100 miles. 37.7 including EV usage.

wrinkle

I arrived at the same conclusion independently and then found your comment - yes, this is a major miss, especially because it could've easily been parameter setting in the 450h+. This is because someone already reported that the RX450h+ auto-switches off the EV mode (even if there is charge for EV mode continuing as EV) when the speed goes above 87 mph or such. All Lexus could've have is exposed this internal setting as a parameter in the UI for us to set. So that we could've just set it to say 60 mph and lived happily ever after.

Does anyone know if one can get the Techstream software to modify this setting or have a dealer do it ? (In my prior Audi, lots of settings like this could be changed with VAGCOM - and we know dealers change few documented settings free of charge at the 5K mile oil change for free).

fbmorris

I purchased the 2024 RX 450h+ and am nothing but thrilled with my gas mileage. As a scientist, I understand the need for accuracy and precision when calculating mileage; however, I’m just going to say this… I’m driving a good sized SUV with the best sound system in a vehicle that I have ever owned and I’m in awe the several times I filled her up. Are you kidding me! Last tank was 92.5 combined mpg and before that, 88.7 mpg. I commute about 70 miles a day. I charge at home Level 1 overnight and charge Level2 at work for about 2.5 hours. I currently have over 400 miles on the trip and another 400 on the tank to go. I routinely get over 700:miles on a tank, this time will be over 800. I drove an Acura TLX which is much smaller and never got more than 25 mpg.

I am in love with this cars’ comfort, class, luxury and sound, but most importantly, top it off with outstanding fuel economy… I’ll never go back!