Installed EV Mode switch today

My husband's warranty just ran out (he now has 80k on his 2005) and so we are thinking of installing one in his car too. I'd love to hear how much money it saves you.

 

Correct me if I'm wrong, but it means you are driving 12 miles per day withouth recharging battery? how many bars it has left after you come back home?

 

I've wondered if there's a niche use for EV.

Our home is a couple hundred feet lower than the last hill on our road. So by the time we hit the final red light the engine's usually shut down, and by the time we get home the battery's within one or two bars of a full charge.

Our new young driver will be using her ride to get to school & work, all within a 1.5-mile circle of the house, both uphill from us, and all in a 25 mph zone.

While I appreciate that battery power is less efficient than driving the wheels directly from the engine, the car also wastes a lot of heat at startup to warm up the catalytic converter to the EPA's satisfaction. Perhaps an EV switch would avoid using a few drops of fuel for regulatory reasons... especially when the battery has enough charge to make the short trips.

And when we get to affordable long-term plug-in solutions, an EV switch will help ensure that the engine doesn't turn on in the neighborhood.

 

When I got my car a few months ago the first mod was the EV switch. The first time I used it was to go to the corner store which is about a mile and a half. I got within a block before the ICE kicked in when it got down to 2 bars. That was the last time I used it for any distance more then a few hundred yards. Now I used it when I have repeated stops that are very near each other, moving the car across the street from one store to another. ( less then 500 yards). Also to impress a few friends.

 

In the long run, you won't save any gas by exclusively using EV mode. There's a simple reason really: you can never recapture as much energy through regen as you use during EV driving. Not even close, but if you could recapture 99% of what you used, you'd still be losing energy.

When you brake, you're recapturing a small amount of the energy that was put into accelerating. When you regen downhill, you're getting back a small amount of what it took to get you up the hill in the first place.

You're also cycling your battery charges more than normal. I'm not going to speculate about if or how much that might affect battery life, but it's something to think about.

EV Mode is great for limited use, but I'd listen to people's warnings against trying to use it for "regular" driving.

 

I've been thinking about getting one since I got my prius (2007, had it 14 months, 33,000 miles).

I drive 42 miles one way to work. Middle is highway and each end is stop and go or back country roads. I have read the expert's opinions, such as Mr. Schaefer in this thread, and I respect their opinions - as well I have a good understanding of thermodynamics, energy conversion etc such that I know the battery is an inefficient power source since most all of it's charge comes from gasoline via an in-efficient conversion path.

However, in my case I think I could raise my MPG a bit by using the EV on my final stretch of two miles. I am thinking I could force the Battery down to low charge (2 red bars for example) during my final stretch. Then, when I start the car the next morning or in the evening to go home, the ICE must run to get the coolant temp up to 185 or whatever anyway. It will also charge the battery. Granted, it will be charging the battery inefficienlty (any transfer of energy has losses due to heat). However, ICE's in general put out much more energy than you use/need, so maybe I would reap a bit of efficiency, and hence greater MPG.

Thoughts/opinions?

Still have not decided, but I'll let folks here know my results if I do get and install the EV.

Thanks!
Daniel

 

Glad you were able to do the EV mod with success I have been told by the Toyota Prius certified mechanic that the software in my 2007 Prius will not accept the EV switch as in the European 2007 Prius. The suggestion from him was NOT to do it or it could harm the high voltage battery. WHY? he said because the software would NOT know when the charge is to low and might discharge the cells too much before the engine came on..... Plus my warantee will be void....:fear:I then asked him HOW would he find that out if I removed the EV switch before I brought it in with a bad high voltage battery.... and he replied, We have ways, even if you clear the error codes by disconnecting the 12 volt battery WOW , that was scary!

P.S. Then I read that the engine lubricates the gears that all the motors connect to (Synergy assembly)...and with out the engine (ICE) coming on and off, the lubrication to that will be reduced, and possibly damaged
Could that be true.....and if it is.........

Norm

 

That's actually a documented technique, so you'll find people agreeing with you. I don't really do that because I don't think the gain would be very significant. The reasoning is sound though: ICE will run during warmup anyway, so why not run the battery down at the end of the day?

EV button install could be a warranty issue. Perform that mod at your own risk. It activates a software mode that's built into the car though, so warnings about possible damage to your car may be overstated.

 

The real issue with the EV mod is that you take your batteries below 40% charge, and you DO NOT immediately charge them back up again (you might park your car with the engine off - thus not charging the battery). There are a few discussions about that issue. You can obviously go on battery only power, but then you need to make sure, if your batteries go deep discharge, that you do full recharge within a day.

 

That is decidedly NOT the real issue. EV mode is a mode that's programmed into your car. It's not a hack or even a mod. The only part that's a mod is adding the button that enables it, because that was left out of the US version of the Prius. EV mode is protective of the battery and will disable if you accelerate too hard, if the battery SOC drops too low, if the ambient temperature isn't good, and probably a number of other factors.

 

Ichabod - I stand corrected. Now I remember others saying that EV MODE is very tricky and will not even activate if there is something going on with the battery charging. So then the EV switch should still be okay for the car, though it is debateable about the fuel savings.

Does anyone have the EV switch with an extra battery for PHEV mode use? Any links or reference to that?

 

You think I'm precious, huh? :hug:

I can now say with confidence it helps mine. See this for more.

And that's exactly the primary application for me, as the link above shows. Except in certain low-speed, low-demand situations, I do not use it for propulsion. Instead I use it to shut the ICE down when I don't need propulsion during warmup.

 

I guess the next question would be the payback of an EV button.

If mpg goes from 60 to 70 for a commute of a few miles, how long does it take to pay back the cost of the EV switch and any installation costs/hassles? And are there any other unpleasant surprises, like having to explain the mod to dealers who are threatening to take advantage of the voided warranty?

 

I don't remember exactly what the Costal EV cost, but I think it was somewhere around $40.

After that the math is pretty simple.

4200 miles at 60 MPG = 70 gallons used without the EV mod
4200 miles at 70 MPG = 60 gallons used with the EV mod

70 gallons - 60 gallons = 10 gallons saved with the EV mod

10 gallons at $4 per gallon = $40 saved after 4200 miles

So if MPG goes from 60 to 70, then it will take 4200 miles to pay back to cost. (If you manage an average of 500 miles per tank, that's about 8 -and-a-half tanks)

Of course, I doubt that the use of EV will be the sole contributing factor to a long term improvement from an average of 60 MPG to 70 MPG. I'm just using those numbers because you asked.

Now if you choose the Radio Shack switch and phone wire mod instead of the Coastal one, you are probably looking at something more like $5 for the mod.

In this case:

525 miles at 60 MPG = 8.75 gallons
525 miles at 70 MPG = 7.50 gallons

8.75 gallons - 7.50 gallons = 1.25 gallons

1.25 gallons at $4 per gallon = $5.

So the mod will pay for itself with the first tank if you can get 525 miles out of the tank.

 

Danny did the math already. I installed the Radio Shack switch. Probably paid less than $5 for that and the wire together, but that number works to keep the math simple.

It's been said elsewhere but it probably bears repeating here (thanks for the reality check): There is a potential warranty issue, so it's at your own risk. At least one Prius owner initially had Toyota deny a claim for a hybrid battery problem because of his EV switch. They later relented, but not without causing some grief and insisting that he remove it. See this for more.

 

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I like the EV switch. I think it can improve MPG.

The trick is to not use it until your ICE kicks on. Otherwise, you're losing all the MPG savings in the ICE re-charge.
Instead, be mindful to stay above three bars, and creative with your EV, like on short distances, or up steep inclines, etc.

Remember, you can be in battery mode up to 40MPH just by gliding(without the EV mod), so you don't always have to use EV when you can.
I like the coasting to recharge trick too!

With good techniques, I'm of the opinion the EV can improve MPG, and it's cool to stealth your way around!!
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