So in one of the owner's manuals, Lexus states that use of EV mode does NOT increase overall mileage. I was surprised by that. If this is the case why have it?
I have been using EV mode after I get off the freeway and drive a couple of miles through our subdivision. I deplete the battery almost completely (2 bars) but make it into the garage. Will this damage the traction battery and should this not improve the mileage. The engine runs in the morning anyway to warm up and the battery charges up then.
I am just wondering how others use the EV mode.

 

We do the same thing and always did with our Priuses too. If you car is moving and the gas engine isn't running, you are indeed saving gas. Using the stored energy in the battery effectively is the key to maximizing your overall mileage.

 

If after using EV mode the battery is almost discharged then how does if get recharged? Mostly by running the gas engine and partly by braking. I'd guess that Lexus is saying that it's a net sum game.

 

Pretty much. That electricity has to come from somewhere and this isn't a plugin hybrid. The engine runs as an efficient generator at low speeds when the electric motor can move the car more efficiently than an engine under light load. At low speeds and with low state of charge, I believe the engine generates power to send to the battery pack and to the traction motor. It's only at higher speeds does the engine drive the front wheels directly.

Is that correct? The Toyota planet gear power split device is a marvelous piece of engineering. It's only recently that Honda has upped the ante by using the electric motor as the transmission.

 

The EV mode is useful when driving at low speeds for short distances. I use it when I leave my garage and drive down the neighborhood street to the main roads. It is also good for leaving the parking garage at work when I'm mainly coasting down the ramps to exit out onto the street. On a cold engine the rpms are higher as the ICE runs to heat up the engine and catalytic converter. By waiting until I get out of the neighborhood or out opf the parking garage onto a main street where I'm driving at a higher mph and the ICE would be on anyway, it does save a bit of fuel. That's the way we did it in hypermiling days and when the Prius was the only car with an EV mode selection.

 

How do you get enough charge to enable EV mode in the first place? It needs at least 2 bars in the battery display. If I'm coming home after stop-and-go city traffic, I only have 2 or 3 bars left and the car shows a Battery Too Low error when I try EV mode. I also don't have enough for EV mode when leaving home the next morning.

However I do get enough charge after a highway drive, also enough for EV mode first thing the next day.

 

If the stack is too low or the engine too cold, it will not allow you to start out in EV mode. I will tell you though that there have been times when I am at two bars and if the engine is warm still, it will start out in EV mode even if I don't get very far on that start. I didn't mean to imply that EV mode always comes on for me, but I do try it every morning and afternoon as I'm leaving home or work and I would say that at least 80% of the time it works for me. YMMV.

Another factor that seems to prevent a start in EV mode is if I have the heater on (or temperature turned up enough to require heat) and the engine hasnt been on since I parked last.

 

On the PriusChat forums, many people have mentioned better mileage with Sport mode. The consensus there was that you achieved your speed faster, then coasting with battery achieves better mileage. I won't try with my ES, as I haven't hit 600 miles yet and I want to properly break in the engine.

 

That's weird. Sport mode on Lexus hybrids uses more battery power because the DC-DC converter dumps 650 V to the traction motor, instead of the usual 500 V. The throttle response is also more abrupt so I find myself launching forward and slowing down more often. In normal mode, I accelerate in the upper end of the tach Eco zone (around 3000 rpm if you show the tach in all modes) before coasting on battery.

I rarely use Sport mode because the steering feels heavy and fake. Light and fake in Eco/Normal mode is fine.

As for breaking in, I'd worry more about the motors. Go easy on full throttle launches and change the oil once you hit 1000 km. Then after that, you can use Sport mode electric boost at every single traffic light

 

I am at around 650 miles and havent hit full throttle yet. I havent even gone more than a few seconds beyond the blue economy side of the dial.