[SteveJH]

During my research of the Prius, I discovered an electric mode kit sold by Costal Electronic Technologies. Is this kit worth getting and why wasn't installed in the US Prius?

 

[Sanny]

run a search on EV mode on Priusonline, and you'll find a wealth of information. Some like coastal tech. some buy the OEM from overseas. probably not on US cars because of regulations of some sort on secondary fueled vehicles, or somesuch.

it still only works at lower speeds, and until the battery gets low and the ICE kicks in and charges battery.

Anyway, run a search and see what you can see. Better brains than mine have debated it.

 

[KTPhil]

Short answers:
1) Excluded from US cars because of EPA regulations requiring testing under all conditions; EV buttom use can't be controlled by the car so all possible combinations would require testing. Same reason you can't get an ignition advance lever on a car like the old Model T had. ;-)
2) Coastal kit works well, is invisible to dealers when car is serviced.
3) Factory button can be installed.
4) "Roll your own" button possible, too. All that is required is grounding a wire to make it go EV.
5) Don't expect better mpg, it's more a convenience for short trips like moving car out of driveway, in parking structures, etc.

 

[tomdeimos]

Absolutely expect better mileage with an EV button. Otherwise don't get it. You should already know if you need it!

It is seasonal, so really cold or hot weather it doesn't work till battery temperatures get to normal. And it can't help someone who just drives fast on highways.

Spring and fall it gets me 5 mpg better mpg on my commute to work daily.

Just the obvious things mentioned a above like moving the car save big, if you do that sort of thing a lot. And it always saves at traffic lights if you cut the engine sooner.

These alone should add up to a noticable change. For the rest there is more controversy but I have tested my commute using it to the max where I think it is appropriate, vs not at all and I see over a 5 mpg benefit most days in spring and fall.

 

[mikepaul]

Short answers:
1) Excluded from US cars because of EPA regulations requiring testing under all conditions; EV buttom use can't be controlled by the car so all possible combinations would require testing. Same reason you can't get an ignition advance lever on a car like the old Model T had. ;-)

So how best to phrase this: if an automatic EV switch exists they need to design a test that includes it, but a manual EV switch is banned because no test the EPA is willing to run can be designed?

When they come up with new test criteria for hybrids, I have an idea what else to change about the rules...

 

[KTPhil]

The problem is testing all the possible conditions. Do you use it all the time? Do you use it only when slowing down to a red light? Using it early in the test cycle will change how it bahaves later in the test cycle, since the battery will be depleted and warmer. The number of variations is large. And for what benefit? Those tinkeres like us already know about it.

Lastly, Toyota wants to make driving a hybrid just like driving a regular car. There are many features designed to "fake" a normal car, like drive by wire programming and the brake stroke simulator. Adding a button unique to a hybrid is drawing attention to how this car is "different," and to many buyers, different is bad.

 

[mikepaul]

The problem is testing all the possible conditions. Do you use it all the time? Do you use it only when slowing down to a red light? Using it early in the test cycle will change how it bahaves later in the test cycle, since the battery will be depleted and warmer. The number of variations is large. And for what benefit? Those tinkeres like us already know about it.

However, given the length of the test cycle, not coming to mind right now but maybe 19 minutes, there aren't that many points in it to say "Let's kick in EV here" that make a difference. Sure, the EPA could argue that every picosecond difference in when it's used will make a difference in the results, but were they actually presented with a 2004 Prius equipped with an EV switch, or was it pulled before they saw one? Unwillingness to test an option isn't a good reason to ban it...

Lastly, Toyota wants to make driving a hybrid just like driving a regular car. There are many features designed to "fake" a normal car, like drive by wire programming and the brake stroke simulator. Adding a button unique to a hybrid is drawing attention to how this car is "different," and to many buyers, different is bad.

I'll go to my death assuming Prius owners are smarter than average, and wanted a different car...