Has anyone installed this?

http://www.coastaletech.com/electric_only_mode.htm

Does it void warranty?
Does it reduce battery life?

Doesn't decelerating and braking recharge the battery? I know the recharge does compensate for all the energy loss, but still...

Tips to improve gas mileage
http://www.thehybridreport.com/tips.htm

Many (me included) have installed an EV switch, Coastal's and others. In my case, I installed a "home-grown" version using a Radio Shack switch.

I could be wrong, but I don't believe it reduces battery life. The Prius' computer is very protective of the battery, and if certain operational extremes that could damage the battery are even approached, EV mode is disabled.

Warranty issues are another matter altogether. One PriusChat member reported a problem (sorry, can't recall the exact issue) that initially was denied warranty coverage because he had the switch. After a month or so of haggling with the dealer and Toyota, they agreed to cover the repair and he agreed to uninstall the switch.

Interestingly, Prii sold overseas have a factory EV button. To my knowledge, there is nothing different about their hybrid systems that makes them less predisposed to EV switch-related problems. The prevailing opinion as to why the US Prius is not EV-enabled seems to be related to emissions rather than potential electrical/mechanical problems.

Fuel savings is minimal, and may be worsened with switch misuse. Recharging the hybrid battery after substantial depletion from EV mode use is less efficient than simply moving the car naturally with the ICE. I use it mainly in two conditions: Short slow speed trips around my driveway or parking lots, and after startup when the ICE isn't fully warm and won't otherwise cut off during coasting or gliding.

For more information, I suggest you do a search on PriusChat. There are dozens of threads there discussing the pros and cons of an EV switch, various models, installation options -- and the warranty issue.

As somewhat of an aside, Coastal has a very spotty customer service record. There are many PriusChat discussions on this too.

Jim

Lifetime fuel mileage:

After learning how to hypermile:

Yes, yes and yes.

I don't think it reduces battery life unless for whatever reason you keep it down to 3 bars (which is where it'll automatically disengage). And that's no different than climbing up/down a hill/mountain every day.

Mods: EV mod, VVT-i emblem, sport pedals, OEM cargo mat, JDM Prius interior footwell lighting, DICE iPod kit, OEM all-weather mats, LED licence plate lights, Phillips Vision Plus

I don't think there is enough data in yet to decide if it reduces battery life. What it does is extend the range of battery or electric only propulsion. It's not "battery only" even when you throw the switch. If you press too hard on the accelerator it will start and run on the ICE and will also do so once the battery is discharged enough or you go fast enough.

You don't need to get the Coastal Tech unit. You can do your own with a switch. Instructions are posted in several places on the web. You can even buy the "stock" switch used on the Japanese and European cars and install it. The software is in all Prius, even if they don't come with the switch.

Personally, due to the limited use of such a switch and the warranty issues, I won't bother.

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

How easy is it to insert/remove this hack? Is it something that you could install and then remove before taking in for service, or is that impractical?

Also are the service shops that meticulous that they can easily detect the installed hack? It's such an obscure thing with no visible button (since it uses the cruise control stick) that I'm surprised they would find it.

They will likely find it if they pull the dash panels. It requires a wire plugged into one of the ECUs, which sits behind the AC vent panel beside the right front door. The wire itself can be pulled out before servicing, but I don't know how obvious any other components of the Coastal switch would be behind the dash. I'm not familiar with it other than that it integrates into the cruise control. My Radio Shack switch is easily seen even without pulling the dash, but I could remove that and the wire easily enough.

Jim

Lifetime fuel mileage:

After learning how to hypermile:

I've noticed that around 32 mph, 42 mph, and 60 mph, lifting the foot off the gas slowly, softly tapping and then holding it steady will put the car in EV mode, though I'd prefer to have an EV switch to avoid using gas in short trips.

I have it but have not installed yet since I may be selling my car. I bought it to make the run to the grocery store (.5 mi away) and back, without firing up the ICE. I know, I should walk...