EV Button Experience

I'm intrigued by the EV button and I'd like to install one on my '06. Has anybody installed this button?

I'd like to cruise in and out of the subdivision using all EV since the speeds are so low.

If I can drive in on EV, I'll be able to deplete the battery a bit before I park. If I can drive out on EV, I'll delay the starting of the ICE until absolutely necessary; when the battery gets low or I get out onto faster roads.

It is wasteful to start a cold Prius with a full battery. There's nowhere to store the juice.

I also don't like turning on the car just to roll up the windows and then having the ICE start up.

I'd like to hear from anyone who has installed this button and their experience with both the installation process and the operation of the button itself.

Brian Herbert Withun

Reply to
Brian Withun
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Please understand what the EV button does.

It does NOT turn your car into an electric car.

The car's software has a routine that keeps the engine off a bit longer, depending on conditions; this would allow you, for example, to move your car around in the driveway or whatnot without the engine running. (Normal operation of the car is to start the engine initially to warm up the catalytic converter, assuming that you're going to drive away.)

In the US, Toyota doesn't invoke that routine. The EV button simply taps into the wiring harness of the computer such that it does invoke that routine.

Now, should the car need to run the engine--it's particularly cold, the battery is far enough down and needs recharged, whatever--the computer will start the engine. The software is ALWAYS in control, and will do what it must to keep the system in the appropriate condition. You could have that EV switch all set up right, and the engine would still start.

This EV mode is good for about 1/4 mile or so. Jockeying cars in the driveway, yeah. Driving out of your neighborhood--no.

You can achieve your goals yourself, with a prudent foot and a decent charge in the traction battery. That's no problem. But you'll never outwit the software, EV switch or no.

Hmmmm. Think about this. If you drive in on EV, you deplete the battery a bit--perhaps below the threshold that the software likes. So when you come back out to the car, no matter what the position of the EV switch, the engine will run to charge the battery.

There is no free energy here. You can't have it both ways.

You say that "I'll delay the starting of the ICE until absolutely necessary." No, YOU won't delay anything. YOU don't control the ICE. The software is in total control. The EV switch tells the software to invoke a different routine as best it can, that's all.

But warming the catalyst is a VERY important factor. It is wasteful NOT to warm the catalyst if you're going to drive the car. And because there is no free energy, you're simply trading off not driving the engine hard now for driving the engine HARDER later on to refill the battery that you depleted five minutes ago.

Which is better--let the engine start up immediately and go gently, using little gas and spewing little exhaust, or hit the EV switch and force the engine to come on later when the battery is more depleted, forcing the engine to work harder in order both to drive the wheels and to regnerate the battery?

No need for the EV switch here. The Prius is just like any other car--you can turn it ON without having it come to READY and be ready to drive. Just hit the power switch twice in a row, without your foot on the brake. Voila--the Prius "ignition" is "on," and systems that require the "ignition" to be "on" can now be run--such as the power windows.

Hit the power button only once with your foot off the brake, and you put the Prius into Accessory mode (ACC)--just like any other car--so you can run the radio and maybe the 12v power outlet.

No need for an EV switch to solve that problem. Use the tools that are built into the car.

Reply to
Elmo P. Shagnasty

My Prius is a european model with the EV button.

I am doing what you describe, moving electrically out of the low speed residential zone and only starting the ICE at the main road. Obviously this'll only work if you have enough juice in the battery. and you don't have a lot of distance to cover. In the end if you deplete the battery to a certain point you'll run on the ICE.

cu .\\arc

Reply to
Marc Gerges

I bought our '04 in Oct '03 (early adopters) and figured out the EV button almost immediately. At first I used it with glee, but the charm quickly went away. At a Prius Club meeting I met Dave Hermance, a Toyota Design Center engineering manager, who said that detection of the EV capability on the car would absolutely void my warranty. He checked for me and said that the EV switch usage would be recorded in the system memory, and would be overwritten only after five restarts. Since a major failure might make five restarts impossible, I saw no reason to retain the EV switch, and have not missed it since.

It's easy enough to do. As I recall, just ground the correct pin (#27, I think) in the terminal block under the rightmost dash panel, which easily pulls away.

Reply to
notaguru

Reply to
Greg

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