EV Switch - What has it done to your MPG?

EV isn't really for better/worse economy. There'll be circumstances in which you can use it for better economy, but mainly it's good for those short moves that you don't want the ICE to come on. For me, it's just a cool, almost free add-on. If you don't want to shell out for an actual OEM switch, you can just use any old switch. The EV mod just taps into a pin on the ECU and when the connection is grounded, EV is enabled/disabled.

 

I only use it for demonstration purposes. To show people how you can drive in electric mode.

 

I use my EV switch primarily to delay startup of the engine when I know I'm going to have to wait at a long light to get out of a parking lot. The light at the primary exit from my work's parking lot has a 2 minute cycle and I invariably get to it just after it's turned red. Now I just hit the EV switch when I start the car and delay the ICE start up until after I clear the traffic light.

 

<div class='quotetop'>QUOTE(CinciPrius @ May 16 2007, 10:02 PM) [snapback]443838[/snapback]</div>

Hello another Cincy area Prius driver. We should get one of the local dealers to sponsor a Cincy Prius club. What do you think?

 

I use mine when I move the car to put it in the garage each night. I also use it when moving through our parking facility at work.

 

<div class='quotetop'>QUOTE(CinciPrius @ May 16 2007, 09:02 PM) [snapback]443838[/snapback]</div>

I'm sure your co-workers behind you just love that! When I accelerate from a standstill, and do so gently enough that I don't engage the engine, the acceleration is excruciatingly slow. Is it any better in EV mode?

My impression of EV mode is that it is not a command, but a strong preference for EV driving. Ultimately, the Prius's "brain" will decide if it can honor your request, but will kick on the engine if it has to. It seems to me that if you haven't driven your car for a few hours that you can't start off in EV mode.

I'd like to drive 3/4 to one mile in EV mode even before the IC system gets warm, but I don't think that is possible. Is that right?

But, what this also means is that the Prius is "smart" enough not to let you ruin it by doing your best Ed Begley, Jr. impression.

I must admit that my original enthusiasm for the switch is waning. Do any Europeans or Japanese out there have any experiences they'd like to share? They have the switch built in! No modding necessary.

 

I suspect that under very limited conditions* there is a very small improvement in MPG, but not enough to demonstrate clearly over the normal tank-to-tank fluctuations. I love the EV switch for the cool factor. And because I just get frustrated when the ICE stays on at times when I think it should shut off.

*Conditions for EV use: When the system is fully warmed up, and the SOC is high, and the power demand is low (steady slow speed on level ground) but the car won't shut off the ICE because it's still in Stage 3 operation, then I like to use the EV. This happened to me a lot in Fargo, where my commute was about 3 miles in 10 minutes.

There are other situations as well. But not many or frequent. If your only reason for the EV switch is to increase mpg, don't bother. It's a very fun toy. But it is a toy, mostly, unless you frequestly have to move your car very short distances, such as letting other cars in or out, or pulling out of the garage to wash it, etc.

You can implement the switch for 2 or 3 bucks for a cheapo momentary-on switch. See the Knowledge Base. The OEM switch is probably the most expensive and difficult implementation. I have and like the Coastal Tech switch.

 

<div class='quotetop'>QUOTE(daniel @ May 17 2007, 07:28 AM) [snapback]444115[/snapback]</div>

Additionally, on initial startup (engine still cold), select EV immediately after ready state but before engine start-up. The engine will not start and EV will operate.

 

<div class='quotetop'>QUOTE(avdavsim @ May 17 2007, 01:23 PM) [snapback]443911[/snapback]</div>

Hello from Japan,

We know heavy use of EV switch is bad for fuel economy, so we have to be very carefull to use it.
Only one exception is when you"re on uphill and approaching to a summit, then you know the next downhill is long enough to recover the battery SOC level by regeneration, you can use up the battery to the summit by EV switch engaged.

We can avoid ICE starting by EV switch when we don't want the ICE start.
Some Japanese hypermilers are using the EV switch a lot, hundreds times a day.
One of their use is they don't move to S4 (keep Prius in S3). They switch on for gliding and switch off for pulsing.

Ken@Japan

 

<div class='quotetop'>QUOTE(ken1784 @ May 17 2007, 09:48 PM) [snapback]444596[/snapback]</div>

Thanks Ken and HSChuck for those facts. Chuck, I was hoping what you said could be done was possible because that would really appeal to me.

Ken, what does S3 and S4 mean? Is S4 the gas engine working and S3 the electric motor only? I'm not familiar with those terms. Thanks.

 

<div class='quotetop'>QUOTE(avdavsim @ May 18 2007, 12:30 PM) [snapback]444618[/snapback]</div>

They are well-known warm up stages...
http://techno-fandom.org/~hobbit/cars/five-stages.txt

Ken@Japan

 

<div class='quotetop'>QUOTE(bigmahma @ May 16 2007, 07:21 PM) [snapback]443763[/snapback]</div>

Because you have to recharge the battery using the ICE, using it up doesn't always help you, unless you can get into at least these two positions (possibly more):

1. If by using it you can prevent the car from idling (as mentioned before) which is an environmental benefit, but may not help you see better MPG all the time.
2. If you have a method to increase the SOC without using the ICE, i.e. a large hill nearby/upcoming, so that you don't have to replenish via the ICE.

It really takes effort to gain MPG using EV mode, but it's use has not been a detriment yet. It is really cool to ghost into a gas station and stealth out (got the saddest expression on the face of an SUV driver the other day, he was filling before I arrived and after I left...not once did he hear my ICE, and when I left, he had a disappointed look on this face as he read the meter showing his gas bill to come).

 

<div class='quotetop'>QUOTE(faith2walk @ May 18 2007, 07:24 AM) [snapback]444819[/snapback]</div>

You're cruel. :lol:

Dave M.

 

Hello everyone .

I Live in what is considered the second largest living center place , sub division , thingy in the west. Basicaly a big community of houses, a giant field for soccer and baseball / softball with recreation and an Albertsons, its about 2 or so miles long and when i am leaving i have to drive about 1 mile or so out to go anywhere with a speed limit of 30 MPH. Would EV benefit me?

 

<div class='quotetop'>QUOTE(AndreJ @ May 18 2007, 10:47 AM) [snapback]445006[/snapback]</div>

You may be able to EV through the whole the whole thing, but unless you have a downhill at the end, it probably won't save you gas since the ICE will allocate more energy to charging up the HV battery back to nominal levels, once it comes out of EV. Even if there was a hill, you may not be able to get all of the charge back, especially in the summer, since the battery and inverter will be quite hot and not able to regenerate at maximum current.

 

I live on a good sized hill, so I do use it to maximize battery use as I'm reaching the top, knowing I'll fill the battery right back up on the way down the next morning. That (plus judicious use elsewhere) seems to have a smallish but positive impact on my MPG.

The more positive but indirect impact on my MPG has been that it resensitized me to how my driving habits (read: speed) impact my MPG. So as much as practical, I'm driving more slowly these days. The view from the slow lane isn't so bad afterall!

And it's just plain fun to show off!

 

<div class='quotetop'>QUOTE(Presto @ May 18 2007, 07:03 PM) [snapback]445298[/snapback]</div>

Well after the 1 mile or so i pretty much go straight to the highway. Unless im going to the city then i go straight down hill , my battery is usually very well charged at the bottom, and then i can cruise in with only the electric motor for quiet a ways.