The Downfall of adding EV Mode Mod to my Car

Make sure you research it here and understand its benefits and limitations before using it. Its value is not in pushing you merrily along with no gasoline for an extended distance. You'll hurt fuel economy if you try that.

I use it mainly to shut off the ICE during warmup (before the ICE shuts down spontaneously) when I'm gliding or stopping. See this for more. For further insight into a potential warranty issue, follow the second link in that post.

I wouldn't buy the Coastal version for two reasons. First, theirs has an approximate 3-second delay for activation. When I want EV, I want it now and I like the immediacy of my switch. Second, Coastal's customer service record is spotty at best. I suggest another thorough search on that topic so you can make an informed decision. It seems folks generally are satisfied when a product is in stock and works properly. Backorders, order follow-up, or tech support are a whole 'nother ball game.

 

Is there anyway to know or test if your battery is beginning to lose capacity?

 

Toyota factory-fits an EV switch to the UK 2G Prius. The battery is warranted for 8 years/100,000 miles. The EV speed limit is 29mph.

Aftermarket EV switches in the US only connect the same two pins together on the ECU that the factory EV switch uses. All the EV logic is in the HV ECU.

Yes, there is less power available in EV mode: only 25kW (~33 hp) can be drawn from the battery, compared to the engine's 76hp and combined 110hp. You do get more power than is possible without EV mode and trying to keep the engine from running (i.e. the engine will kick in, in normal mode, before EV mode would turn off - the car doesn't like draining the battery at that high a rate, generally).

I agree that EV mode is not a route to improved fuel economy. In fact, it's usually worse. (Someone in Toyota PR seems to be giving the wrong information to the press, because they keep mentioning it in reviews!) It's useful for moving the car a short distance when you know you'll be shutting it down straight away - moving in or out of a garage, moving around a car park. Toyota advertise the 'silent getaway' to avoid disturbing your neighbours.

 

On the North American model it's 34 MPH.

It can in limited circumstances and if used properly. If it's used primarily to force electric propulsion, I agree. However, as my previous link shows, in certain driving conditions fuel economy can be improved by forcing the ICE off during warmup gliding, coasting, or braking.

 

i'm kind of suprised that there were not many replies to this thread. My priusC came with an EV mode button.. and it cuts out at 24 mph or hard accelleration.. I was hoping the mod would prevent it from cutting out.. and now that i read this thread i wonder if there is a way to change it to cut out at a higher speed?

 

Why do you want to do this? You won't get better MPGs and you could hurt your HV battery, substantially shortening its lifespan forcing it to run in EV. The car, after all, is not an EV. It is a gasoline power car with electric assistance.

 

This mod was specific to North American (or just U.S. ??) Gen2 Prii, which came with no EV button at all, possibly for warranty reasons. Since the same vintages in other world markets did have the button, and the hidden internals were the same here, this mod thus let U.S. models access the feature.

Gen3s, including your 'c', came with EV buttons worldwide, so this sort of mod wouldn't get anything you don't have already.

Different markets do have different cutout temperature thresholds. But I don't recall any separate mods to change those, or to change the cutout speeds.

 

It shouldn't be hard. Just wedge a Prime's battery in the back so you have the power source and a Prime's transaxle and inverter under the hood for power delivery and gearing ratio along with the various control systems and you're good to go. New EV top speed will be 84 mph. In managerial parlance, "How hard could it be?"

 

The car was not designed to operate as an ev at speed since it has a very small kw battery. EV is more of a party trick in most Prii except the Prime models. Back in 2004 California mandated a 150,000 hv battery warranty so Toyota gave 150k to those buyers and 100k to the rest of us. Most think that is why the US gen2s had no EV button when the same car in other countries did. There were other differences by country like auto parking that the US models did not get.

However the system can and often does operate ev only at higher speeds in normal hybrid mode. Anytime the system is Ready and the engine is not running, it may be in ev. Usually the hv battery is used to supplement the gas engine at speed. That is why Toyota's system is called a parallel hybrid.

Even if a software modification could be made to deplete the battery faster for a longer time, the battery would overheat quickly since it is air cooled by a small fan. Most full EVs use water cooled batteries to keep them within safe temperature range. Except the worst EV, the Nissan Leaf, which has a reputation for poor battery life.

I believe the Toyota system has a failsafe mode that allows longer ev operation at higher speeds when you run out of gas. I had that happen in a 2008 gen2 at highway speeds for about a mile. The dash lit up but I still had speed control as I pulled into a gas station. The hv battery was extremely low but restarted the engine after fueling. It ran but was very underpowered for a few miles since the battery could not add anything to the total hp. I never again experienced that kind of reduced power. So the battery is used a lot in normal driving at low and at higher speeds. It is used to achieve adequate power and high mpg with a purposely underpowered gas engine.

 

Right up there with the rhetorical "What could go wrong?", which I quickly learned to really mean "Duck!"

 

Which in turn is closely related to Bubba's last words, "Hold my beer and watch this!"

 

At least I never heard that one from anyone signing my performance evaluations or paychecks.

(Yes, I heard "what could go wrong?" from a boss too many times, and not as part of any due diligence query.)

 

I purchased an EV mode mod for my ‘06 shortly after I purchased in ‘08.
I use the cruise control stick to operate it.
Once the speed exceeds about 32mph the engine starts up.

At the time, it was the only EV mod available.

I used it when I left my house each morning.
That is, I live on a long downward hill.
Sometimes I travel 3miles in EV coasting at 32mph.

it’s a gimmick that increases my overall mpg.

 

I similarly live atop a hill and start out with a downhill, but I never use EV. Instead, I encourage the engine (ICE) to come on immediately and use the cruise down the hill to allow the car to warm up from stage 1 to stage 2 (see the link in my signature Hybrid Warm-up: 5 modes of Prius Operation. to more fully understand the warm-up stages). In addition, the road is not so wide and has lots of curves and turns, so 24-25 MPH is a safe speed and I apply a little brake pedal to increase the regen and hold it at that speed. More often than not I have 7 bars (1st green bar) by the time I get to the bottom. I then allow the car to use this energy as it wishes by neither encouraging nor discouraging the car to use the battery. I continue this regime until I have reached stage 4 of the warm-up. After that, I just do the usual (for me) pulse and glide. When pulsing, I encourage the engine to come to speed the car up as this is a better use of energy and minimizes energy conversion losses. These two habits give me the best bang for my (MPG) buck.

YMMV.

 

Your battery will go bad sooner. You may be inclined to use ev for the last mile, put car away w low charge. The next day the ac will deep cycle the battery upon startup. Not worth it. Don't use it.

 

Don’t understand how do you just add an EV to a non EV? Wouldn’t it be less expensive and less work to simply get an EV? Maybe I’m clueless.

 

Guess I should watch this again, have the DVD, or was it Bluray?

 

Gen 2 Prius has EV capability in a very limited way. In Europe, they have an EV button. In North America, the programming is there but the button is not. It's a simple matter of installing a push button without bounce and wiring one pin to one of the pins in the ECU behind the glove box and the other pin to ground. A pulse on that ECU pin pulling it to ground before the ICE starts will switch the car in and out of EV mode. About all it's good for is moving the car into or out of the garage without starting the ICE. Can't be driven far enough to be useful as a driving mode but a nice way to avoid deciding between a cold shutdown or sitting there waiting for it to warm up before turning off the car after moving it a few feet.