EV Mode - How does it work?

It is too good to be true.

When the ICE eventually kicks on to recharge the battery, you'll use more gasoline to recharge the battery than you would have if you just ran the car with the ICE. So, while any individual short trip might compute to infinite MPG, the MPG for the tank of gasoline will be worse than if you had not forced EV for entire trips.

As for your statement "If I accelerate normally will the ICE actually not turn on until I reach 34 MPH?", it really depends on how you define "accelerate normally". If you accelerate fast enough the vehicle will disable EV and start up the ICE to give you the acceleration you are requesting.

Furthermore, I recall someone mentioning that there are temperature constaints on EV, so depending on the Temperature (of the battery? of the air outside?), you may not be able to use EV at all.

Finally, 2 miles is a long way to go on EV. The Prius HV battery really isn't designed for extended driving. It is more of a boost and buffer. If you've got a stiff tail wind, or decline most of the way, you might make it, but in general you'll probably find that the ICE will kick on and burn through all the fuel you just "saved" plus a bit more before you make it the full 2 miles. If you manage to get all the way to work, you will certainly use up the fuel saved plus some additional on the way home.

 

You have to re-charge the battery by burning gas some time. It's still not plug-in

 

The EV is worthless. I installed one in my 2004 when it was new. It works as advertised. With a fully charged big battery (Step on brake and on gas until the bars all turn green), if I go slow (under 32mph) on a level street, I get about 1/2 mile before the battery gets low enough to trigger the ICE and the three beeps. I used to use it for demos but haven't for three years.
All the talk about plug in hybrids is worthless political pandering until a Lion battery with 3-5X the capacity and some software changes might enable a 3 mile trip without the ICE. You would have to plug it in at night to charge it up and then hope you could get to your destination and back. It's a long way away and for trips that short, you don't burn that much gas anyway. A 20-30 mile range would make it practical.
My wish list starts with an electric turbo booster to get me over the long, steep, passes without having to go slower than the rest of traffic and an electric drive motor in each real wheel for 4WD in the snow.
After that, I'd like the auto parking feature, an optional longer front seat track and that's about it.
I would scrap the air bladder in the tank and the radiator coolant thermos system. They may reduce emissions but add to the cost and complexity.
I have 45,000 miles on my 2004 and think it's the best car I've ever owned. It really is the single best answer for our oil problems.

 

Hi David, welcome to PriusChat! :welcome:
If it's flat and only 2 miles, why not ride a bicycle to work? Better for you and the world.

 

I was riding my bicycle into work here in Phoenix after the weather cooled off until my bike was stolen.

After some consideration EV mode sounds more like a toy than anything else. Perhaps coupled with an Enginer or something of the sort it could be useful since you'd have a way of getting back the electricity without firing up the ICE.

 

(Wonder how I missed this thread first time around.)

It's more than a toy when used properly and in the right conditions. Its best use is NOT to force electric-only propulsion, but instead to force ICE shutdown during warmup when it won't shut down spontaneously while coasting, gliding, or braking. See this for more.

 

I have considered getting the EV mode mod for my car, since I could use it at each end of my commute - when I pull off the highway to my work location, I have maybe 1/4 mile (mostly slightly downhill so I coast anyway) and then on the way home once I pull off of the highway into the neighborhood. I USUALLY get all the way to my house on battery power anyway, but if I go swing by the mail box, I end up going maybe 1/3 of a mile after pulling off the highway. I think that is a situation where I'd turn on EV mode.

I also tried looking around for the mod, but couldn't find a link to it. If anyone has it handy, please poast it.

 

Check the thread I previously linked. Within that is another link that takes you to a description of my installation and, later, a replacement switch.

 

I have a 2005 with EV on the light flasher arm, and a 4kwhr Enginer kit. I agree that the EV works best with the plug-in capability. I can go 4-5 miles in EV in town driving at 25-30mph with stop lights and stop signs. The key to this is the recharge that the Enginer kit gives.

Thanks,
Dan

 

I used to drive about that far to work. I also had grocery stores, restaurants and other shopping nearby - far enough to drive but a little too far to walk (I have sorta bad feet).

For way way less than the cost of a LiIon battery conversion, I bought a nice used scooter. They're tons of fun, can hold a shopping bag or two and get around 90 mpg going up to 65 mph. We sold our first one when we moved and got the same amount as we'd paid several years and several thousand miles earlier. Now we have this newer one and use it every chance we get.

 

Danny Hamilton's post is spot-on. Here's a way EV can be useful: Slow speed in a residential area with lots of stop signs. Accelerate from the stop using the ICE. Engage EV for the steady-speed stretch to the next stop. Engage the ICE again to accelerate.

Once the battery drops to 4 or 5 bars quit using EV and allow the car to use the mode it chooses.

 

I've had it for a couple of weeks now (Sigma's JDM EV switch). And after having my fun torturing the poor traction battery I've found the limits. Now I use it exclusively to get on the move when the car is cold, avoiding the idle for the sake of warm up waste. Pulling out of a parking lot to a main road, out of my garage and down the hill to a main road, etc. Once on a road I either turn it off or accelerate hard enough that it shuts off.
Probably no real gain but it's hard to tell, so many moving parts in the FE equation all the time. It just makes me happy to have that control.

- D

 

When the engine is cold, the Prius tries to avoid putting a load on it for the first few minutes, drawing heavily on the traction battery instead. If you force EV until you need the power of the engine, you put undue stress on the engine.

You are better off allowing the engine to run during those few minutes of gentle driving after first start-up so that it's warm when it needs to deliver power.

 

Undue stress on the engine or undue load on the traction battery? My main point is to be moving along while the engine is warming instead of creeping through a parking lot or backing out of my garage.

At any rate I don't think that pulling away from a stop sign and accelerating normally up to 35mph should be a problem, cold or not. Plenty of people live right on streets like that and have no choice. Not like I'm dropping it down in front of a christmas tree at a drag strip!

- D