Okay, I want the truth. Has anybody else played "Let's try to keep it in EV mode all the way to the grocery store and back?"

We typically have the engine kick in once or twice if we accelerate too fast... but last night we made it there and back (a half mile trip) solely in EV.

While cool, doing this actually wastes energy and drops your mileage. The reason is you loose a lot of energy discharging and charging the battery. 50% efficiency has been put out there. Add to that the efficiency of the gas engine when it eventually has to recharge the battery - around 25%, and you can see it's a pretty big issue.

The engine and cat must have been warm when you did this, as the engine will usually start as soon as you turn the car on if it's cold.

Pearl is a
2007 Driftwood Pearl Prius
Package "B" (everything but leather, nav, and rear camera)

David, thank yo ufor the quick education. We thought we were being so smart doing this.

And YES you are correct. We were only able to pull this off when the engine was already warm.

if its any consolation, I've been playing this game too

LOL... I didn't stop either. I know we aren't supposed to do it, but it really makes driving a small errand fun.

I'm not sure this is entirely all that bad for FE.

1. If you did this and your battery is low at the end of the day, in the morning when you start the car, the engine will start up anyways, and you use it to move the car, but you get to recover the motion with regen. If your battery was already full in the morning, you cant recover as much for the time your ICE is on anyways. A net gain.

2. If you're house is on top of a hill, this is generally good because you can regen going down without ICE. Not so much if you had gone up without ICE, but if you did, you could go down and get a net gain.

3. Much [well maybe, some] of the time the battery is full due to recharge during cruising with ICE, that there's no room for regen capture (or less recharge efficiency). If you try running on EV a lot, you'll keep the battery low for capacity to regen. A net gain, vs. stopN'go without capacity to recharge.


I know, I know...if you're just staying in EV for the sake of using only electrical energy, then your FE will suffer...as David indicates...but there are some circumstances where it helps...

BTW, I do this every chance I can...it's a fun thing to do, esp when you have to run boring errans...

Yes, and don't go by anything -I- say. I'm still figuring this HSD system out, and it's looking like it's more complex than I can understand. I was just repeating what I read that sounded correct technically.

Pearl is a
2007 Driftwood Pearl Prius
Package "B" (everything but leather, nav, and rear camera)

One other method you can try is using EV mode as you approach the end of a trip. This will deplete the battery down. When you startup, the engine will run for warmup anyway so charging the battery will be "free". Otherwise the warmup ICE time is wasted energy. This will boost mileage considerably.

Alden Bowles
2005 Toyota Prius II HSD

I want a Plug so I can have a fully charged battery to begin with.

Only charging battery from outside will not do it.
The catalytic converter needs to be warmed up too.
The car will run the engine until the catalytic converter (CC)
goes up to a predetermined temperature so that the car
conforms to the smog emissions requirements.

Now if you put an electric heating coil around the CC and heat
it from the plug, that will solve this cold start problem.

I have noticed that when I do pulse and glide for a long
time in cooler temperature around 50F, the engine comes
on even though the battery shows good charge. This must
be because enough hot exhaust gases are not going through the
CC to keep it in its specified temperature range.

My mpg suffers terribly due to this. If the car could start
straight away in EV mode always, I sould have crossed 45 mpg
by now. I am still at 38-39.