My Prius needs a battery, Toyota denies warranty due to EV button

efusco

Bob,
sigma automotive sells the EV button...but it won't do you any good if you have an '03. The mod only works on the '04+, The '03 and earlier were not programmed for that functionality.

Bob Boyce

Thank you Evan

Been a long time since I have been to this site and have learned a lot about the Prius since asking that. I now have a pair of the NHW-11s, and bought 3 very good spare HV battery packs for them from salvage yards. I bought a full manual set from Toyota, and located the HV ECU to Engine ECU harness wire that allows the engine to be switched off for EV mode operation. I tested it and it worked, but decided not to implement it long term after considering how it would likely impact the service life of the HV battery. I am up to about 158K miles now on that original battery and it is still going strong!

I did discover a way to implement lower cost PHEV using spare HV batteries when I was testing one in a NHW-11 while the original HV battery was still mounted. It requires data switching, but essentially you can parallel most of the HV battery connections. The data path is split and data allowed to flow from the HV ECU to all HV battery ECUs at the same time. This keeps them all synchronized and responding to the HV ECU. However, only the active HV battery ECU is allowed to actually communicate back to the HV ECU. All onboard HV battery packs can be carefully charged fully via external power, then used one by one until all are equal in charge at normal hybrid operation levels. I do not recommend running any of the HV battery packs any lower than Toyota permitted in order to avoid HV battery damage. When a HV battery ECU detects full charge condition however, the will NHW-11 operate primarilly in EV mode to dissipate the excess charge detected.

Bob

Mjolinor

Do you have any specifics about this, which wires etc.?

Scrap Prius in the UK are as rare as hens teeth but you do get them occasionally and, time permitting, I will get stuck into making EV mode work on a mk2 (NWH11)

bwilson4web

Actually it has a use for auto-stop when the vehicle is stopped and the coolant is less than 70C. This would avoid burning gas when stopped at a light.

Is it a 'level' signal or digitally encoded?

You don't get an error code when using it?

Bob Wilson

Floyd2

From what I've heard the EV button had to be left out due to a class act between GM and Toyota. GM claimed the Prius would be an Electric Vehicle as well as a Hybrid car.
So it seems you owe the lack of an EV button to GM. For the record: this is hear say but it sounds credible.

I'm glad the EV button was standard on mine, makes it much more fuel efficient.
The Prius system is designed for use of EV mode, the US version just as well. The only thing different in the US model is that the button and a single wire are simply not there.
Toyota knows this and that is probably why Naterprius got his battery for free after all.

Anyone who added the EV button themselves and having problems with the battery, simply switch the button temporarily for a blank before taking it to the dealer.

Glad it turned out well for Naterprius in the end.

Floyd, Netherlands

Dan.

Nate, congrats on the positive outcome and I'm sorry for your pain.

I am a bit curious about your battery condition and premature failure. I take it that you probably have more EV experience than most of us, so what follows is more of a generalized thought than my opinions on your particular issue.

What has me curious is that fact that your battery fans came on. I have had that happen and did some simple mods to fix it. Turns out that the inlet vent wasn't getting good airflow into the battery, so I moved the car seat to the other side of the car. Also my trunk well was full of stuff. This had the effect of putting a blanket over the battery. It kept the heat in and made it harder to vent. The third aspect to the problem was high amp assist and high amp regen. To fix the trunk well, I simply removed it and kept the back uncovered for a few days. Battery cooled much quicker and wasn't going all thermal nearly as often. My trunk now holds nothing! Ever!! Eventually I hope to be able to read battery temp without a CanView so I can keep a better eye on it. And as for the heavy Amp regen and assist, I just baby her a bit more so I don't encounter those situations as much. Makes me bit more pokey on the on ramp, but there you go. Now my battery rarely gets outside the blue range now.

As for the EV mod. I almost hired my dealer to install it. They certainly offered on multiple occasions. In the end I opted against it. I think they were gonna charge $250 labor to do it and that's when I decided against it. My dealers policy is that if it's a Toyota part, they will install it. Since I got the sigma OEM button it qualified as a "Toyota" part.

I think Toyota would still shy away from a media circus but it's such a technical issue for the average couch potato, that they may just roll their dice with the PR department leading the charge.

As for my info on why EV was left out in the US. I was told it was to simplify emissions testing. EPA had a fit over the EV button and Toyota found it easier to cut a wire than to fight the US bureaucracy.

11011011

__________________

Best commute = 14.3mi @ 114 MPG (sg2)
Best (non-trivial) tank = 1101mi @ 91.2 MPG (fcd)
MPG Centurion-Hybridfest 2007-Prius II-26mi @ 106 MPG (sg2)
Dan <11011011> @ CleanMPG.com

JimboK

Dan, Nate hasn't been around for over a year and a half (unless he's lurking).

Dan.

Yes but anyone with a Rav4EV marks high on my envy-o-meter

11011011

Floyd2

I bought mine a few weeks ago and have used 63.5 MGP on average until now. Others told me efficient and experienced use of the EV mode can increase that to over 65 and almost reach 70 MPG on the standard P2 version.

Don’t know if this will have a negative effect on the battery or it’s life expectancy Dan. I don’t think Toyota would take a risk adding this button unnecessarily, thus receiving more claims about worn down batteries within the warranty period. Warranty here is 9 years and up to 180.000 kilometers, that’s about 105.000 miles.

You can easily install a button yourself, seach for calcars and EV button. The have a nice howto PDF on their website. It’s a matter of one single wire (unfortunately from the back) and a simple button. Would save you $ 250,-. Maybe there's even an unused wire in your version, I don't know.

Your envy-o-meter? Seems to be a downside to the Euro version after all, we only have the odometer.

Floyd

vertex

I doubt EV mode would have much effect on battery life. It uses the same operating profile, with the low SOC the same as in hybrid mode.