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Hi there!

I find it very useful, specially when running errands requiring short drives on surface streets with a speed limit of 35mph. Since I installed the EV kit my mpg average increased by almost 10%.
I also use EV when I won't be a rock in the rapids, i.e. whenever engaging it won't create a line of impatient drivers going 20 mph behind me... :wink:
 

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I use it
1) to exit multistorey or underground carparks to minimise exhaust fumes

2) tootle around the campus

3) delay the engine start til I reach the main road

4) keep the engine off on the downhill stretch back home cause I know the engine can be off and don't need it running
 

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I sometimes use it when I add air to my tires. The compressor runs better in READY mode, since the DC-DC converter is supplying 14V over the nominal 12V the aux battery provides alone. But I don't want the engine to run for warmup just for this, so I put it in EV mode.

Legally, Toyota probably can't void the warranty, unless they can prove that you damaged the HV ECU or the harness with it, but they have said in their FAQ that making it plugable AND adding a switch to make it run in electric would void the warranty. It's the AND in that statement that seems to be a loophole. However, US and Canada are the only markets that don't have this switch from the factory, yet the HV ECU has the programming for it. All Coastal's mod does is provide a fancy way to send the EV signal, the same way an ordinary switch would; another reason Toyota would have a tough sell in court to deny warranty.
 

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EV mode is used daily. At least when I get to the end of a trip I stop engine about a block away, or when approaching a red light to stop engine early. Also used in parking lots etc when going slow. Or just for moving car in driveway.
These uses are convenient but don't save a lot.

The real use is for driving in two special conditions:

1 Fall and Spring when I go all the way to work without getting to stage 4 it is the only way to ever have the engine go off at lights etc.
2 In traffic jams It lets me block excess engine starts and stops.

These two situations buy me an extra 5 mpg minimum, but only when these conditions occur.

For real winter note that item 1 doesn't work, as a cold battery blocks EV mode entirely.
Also blocked when I am just moving the car to clear the driveway of snow.

Pretty much all the rest of the time I use battery mode when I can, but don't need ev.
 

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DanMan32 said:
Legally, Toyota probably can't void the warranty, unless they can prove that you damaged the HV ECU or the harness with it, but they have said in their FAQ that making it plugable AND adding a switch to make it run in electric would void the warranty. It's the AND in that statement that seems to be a loophole. However, US and Canada are the only markets that don't have this switch from the factory, yet the HV ECU has the programming for it. All Coastal's mod does is provide a fancy way to send the EV signal, the same way an ordinary switch would; another reason Toyota would have a tough sell in court to deny warranty.
Another thing to note is potential liability (for Toyota) of a Prius owner driving in EV mode and then hitting a pedestrian... I'm sure the legal team over there has warned management about the nightmare scenario this would cause (due to legal deeppockets approach) ... unless there was a strong disclaimer. So my take is that they won't neccessary void your warantee, but this is one of those things that makes it clear that if you get into an accident with your silent Prius and a pedestrian, Toyota is clearly not at fault. Probably the only reason they left the EV switch off the car here... we're way too litigious a society for risky innovation.
 

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Actually, I see LESS liability from Toyota in driver-selected EV mode. The car can enter this mode all on it's own right now. An accident in EV mode that the car did NOT select would point toward the driver as liable, not Toyota.
 

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KTPhil said:
Actually, I see LESS liability from Toyota in driver-selected EV mode. The car can enter this mode all on it's own right now. An accident in EV mode that the car did NOT select would point toward the driver as liable, not Toyota.
That was my thinking. My car goes silent in parking lots all the time all on its own. I hardly use EV. The only time it makes noise is if the AC is on (which is most of the time) so that the cooling fan motor and compressor are running, which almost sounds like ICE.
 

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No, you can add your own. The electrical objective is a momentary grounding of pin 27 on one of the connectors to the HV ECU. I personally did that with a pushbutton switch installed next to the dimmer. You can also obtain an OEM switch, though that can get pricey, since it has to be imported.
 

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To answer a PM on instructions on how to install an EV yourself:

http://priuschat.com/EV-SWITCH-Install-pdf-s-t9252.html



As to the question on another post as to whether this is efficient, the short answer is, in most cases no. Plenty of topics on this, but I'll summarize.

Whenever you drive under battery power, the battery somehow has to be replenished. There are only 2 ways to do this: regen braking, or charging with the ICE using MG1. Transferring energy from one form to another always has inefficiencies. Think about taking a glass of water, and transferring it from one dry glass to another. Some water remains in the previous glass, which is loss. In the realm of energy, this loss is usually in the form of heat.
Now, if the total transfer inefficiency in EV is less than the loss due to inefficiency of the alternative means of energy, that is, driving with ICE, then yes, EV might be better in that particular case. But usually, the transfer inefficiencies are greater than if you just drove the car normally and let the car decide when to be in electric or not.
Sometimes though, on really short trips, you might be able to defer the warmup to a later trip.

However, there may be times you might want to go EV briefly, such as moving the car out of the garage to wash it, or like in my case, for extra power to your air compressor running at 14V in READY mode rather than 12V in ACC.
 
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