New NX 350h owner here.
Was curious what the EV Mode button does. From what I can tell, it seems to activate the electric motors, which would be nice... if it worked.
In my case, it seems I get the message "EV Mode not available" most of the times. Only once I got it "available" and was able to pull out of my drive way on electric only. Unfortunately, by the time I got to the mailboxes (some 500 feet), the engine kicked in.
So, what does that button do?

 

From what I read and have tried. . . The EV mode is for quiet driving mode for under 15/20 mph such as for schools, churches, funerals. It’s a quiet driving mode. I’ve used it about 2 times. It switches out of EV mode once you go out of 15/20 mph. Is it needed probably not! Remember, while in EV mode your pretty quiet so be aware of pets, children, joggers, adults etc.

 

This EV Mode function seems very inconsistent.
I've seen Youtube reviewers claiming that it should work below 30mph. I tested yesterday and it seems to turn off at 25mph.
Youtube also claim 37 miles of range on electric only. I couldn't get more than one mile.

 

Today, I tested the EV Mode again. It kicks itself out upon reaching speed of 19mph. There is a message that says so - speed exceeded.
I think this EV Mode button is useless. The car goes into EV automatically anyways, whenever it thinks it should. The button is for us to override that, but there are so many limitations that it's practically useless.

 

I think you're confusing models. The 37 miles is for the plug-in 450h+, not the regular hybrid. I routinely get over 40 in my plug-in hybrid model. Totally different system and battery capacity.

 

repost - My take on the EV button goes back to my early experiments with hydraulically
controlled Automatic Transmissions. When trying to outthink the shift point logic I would
row the shifter back and forth, press and release the throttle and generally try to impose
my will on the transmission. Didn't make any difference in performance (was not concerned
in the least about fuel economy, gas was 50 cents a gallon at the time!) and thankfully I didn't
grenade the trans in Dad's car! The built in shift controls were appropriate almost all the time.

As shown here and other CL threads the EV Mode (not Drive Mode ECO) does not really offer
an improvement over the designed in balance between IC and EV that Synergy Drive is built to do.

 

This car (and perhaps most Lexus models of recent) are full of unnecessary complexities.
Case in point - this EV button. It's pointless. Let the system figure out when and how to go into EV. If they decide to let the driver override, they better let us override, otherwise they risk frustrating us all.
Just get rid to that useless button (and related wires, logic). They'd save $5/car. If they sell 200K cars, that's an easy $1M and everybody is happy.

 

I believe it is for consistency - or the not-willingness to change - between models.

On NX350h - I found it useless. Up to 20mpg it turns off by itself. I use it for garage in and out and maybe drive to the mailbox in the neighborhood...

 

We have less than 500 miles on our 2024 NX350h. I use the EV Mode button a lot. I find it frequently, though not always, available - depending on battery charge. I turn it on first thing when I turn on the car and go to pull out of my garage and parking lot. I use it when I slow down in traffic. I use it when I come to a stop light so that it’s battery generating forward acceleration rather than gas. It’s my understanding that a car uses the most gas trying to get up to speed vs. maintaining speed - so that’s my operation theory for when to deploy the button. It is absolutely true that it will shut off if you press the accelerator too hard or when you get above whatever low speed it decides. Sometimes it decides 16, 17 or higher. The highest I’ve seen is about 27 and I was going downhill. Anyway, for me, it’s become sort of a game. I just use it when I can and don’t worry about it when I can’t or when it won’t deploy.

You can also see the battery status on your monitor by selecting that under car. In my case, I find it won’t deploy if only 3 of the bars are lit. YMMV. Happy Driving. Love our Lexus!

 

Two weeks into owning a 350h and I’ll say I find the EV mode mostly useless…..but there’s one specific use case I like.

usually just driving with a light foot in neighbourhood will keep the car in EV anyway, even past the 40km/h limit, so that works better usually, but specifically when parking and backing in and out of the garage I like having EV mode enabled to guarantee that the engine won’t come on and spew fumes into the garage.

thats it really. Other than that, it’s pretty gimmicky.

 

EV mode allows the motors to put out more power before bringing in the ICE engine -- nice for when you need it, but the car needs to be already warmed up and it runs down battery state of charge quite a bit. I don't think it's particularly fuel efficient at higher speeds and in the long run using EV mode all the time seems to hurt fuel efficiency (eventually your ICE engine will have to kick on as a "generator" to bring up the SOC when it falls too low). I find in the long run it's generally better to keep your battery SOC in the mid-higher range (right around 6 bars), and save this battery energy for assisting the ICE engine.

If you have a long downhill section coming and you have high battery SOC heading in, you can purposefully run down the battery a bit before the hill, creating more room in the battery to get the most out of regen down the hill. EV mode is sometimes useful here before the downhill, especially if the road has small hills -- it can keep you in motors only / ICE off with higher power output limits than you can without EV mode. You still need to be at lower speeds (<25 mph) to stay in EV mode, but you can use the extra power to crest smaller hills and still remain EV only (when EV mode is off, ICE will kick on more readily as you're climbing small hills). Using your motors will run down your battery SOC a little bit - down to about 3-4 bars - and then the long downhill section will fill your battery back up.