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Prius EV Mode Button

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Revision as of 01:50, 17 August 2007 by Rjf (talk | contribs) (→‎How the EV modes work: merged information from Prius EV Mode)
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Enabling the EV Mode Button, The secret missing feature.

The EV Mode Button is a standard part of the Japan and EU Prius but was not installed in the US versions, perhaps because of extended warranties in Ca due to AT-PZEV regulations and qualifications criteria. The US Prius is still entirely aware of the EV Mode though it can never get the signal or command to enter or exit the mode because the wire and button are missing. EV Mode is a very enlightening feature as it encourages the Prius to stay in its electric mode for far longer than it normally would. It will normally drive 1 to 2 miles on a fully charged battery, after which it must restart the engine using gasoline to recharge the battery. It is not a good idea to fully cycle the battery often as this decreases any battery's life and is not helpful for mileage if used improperly. If used correctly is can be advantageous for times when you know you won't need to start the engine. It's also fun for showing off and offers a small glimpse of the potential of electric vehicles.

The EV Mode function itself is activated and deactivated by momentarily grounding the H14 #27 pin on the HV ECU located behind the glove box(s). CoastalTech.com (ph) has a 3-wire EV Mode Button kit with easy instructions which allows you to turn on and off the EV Mode through the Cruise control stalk. prius-evbutton-install.pdf <ref>Media:Prius-evbutton-install.pdf from http://www.calcars.org/prius-evbutton-install.pdf</ref>from calcars.org and EV-button-Y.html from vfaq.net have more information for "do it yourself" type people. This factoryEV.pdf <ref>Media:FactoryEV.pdf from http://www.scubadivervideo.com/Files/factoryEV.pdf</ref> by ScubaX at PriusChat talks about the OEM EV-Mode button and dimmer switchs white/black wire which is ground(-) and the grey wire which is illumination control, there doesn't appear to be any OEM EV-Mode status indication. The recirculation button on the steering pad might also make a good EV Mode button but it's not a simple switch and is instead a variable resistance control connected to the climate control system. You can also take a look at the PiPrius conversion process#CAN-View_Version3 page which discusses one particular PHEV conversion but includes some steps regarding the EV Mode button installation.

How the EV modes work

  • This maillist Y!ahoo post describes in more detail what to expect from various EV modes in the Prius.

Things that cancel or prevent EV Mode use:

  • Pushing the EV-Mode button cycles into and out of EV-Mode, if allowed.
  • Defrost not selected (and possibly some other climate control selections).
  • If the battery voltage falls below 180v EV-Mode is canceled.
  • When the battery reaches 2 out of 8 bars (>=45% SOC) EV-Mode is canceled.
    • Battery must be at or greater than 3 out of 8 bars (>=50% SOC) to engage.
    • Battery must also be lower than 8 out of 8 bars (<=80% SOC) to engage.
  • Speed must be below 34mph (55 kph), above which EV-Mode is canceled.
    • Other EV modes such as "Stealth" up to 42mph and "Warp-Stealth"/"ICE Spin" above 42mph regularly occur when there is ample battery energy and low power demand without the use of the EV-Mode Button.
  • If the accelerator pedal is depressed more than about half to 3/4 of the way down (<=120 out of 255, corresponds to approx. 120A or 24kW) EV-Mode is canceled.
  • Extremely low or high battery temperatures will prevent EV-Mode from engaging.
    • The battery pack must be < 107°F in order to engage EV-Mode.
  • A CCL (Charge Current Limit) of <=50A will cancel EV-Mode.

Other Notes:

  • The ICE will start 7 seconds after vehicle startup unless EV-only mode is entered during that time.
    • Once the ICE starts the first time during a trip, it will not stop or allow EV-Mode until it has warmed up.
  • The A/C compressor is electric, and the A/C will work while in EV-only mode.
  • When the EV-only mode is entered, the hybrid model screen will show. A beep will be heard only if that screen wasn't already showing.
  • Three beeps are heard whenever EV-only mode is requested but not allowed, and when it is auto canceled.
    • One must wait around five seconds before a new EV-only request is acknowledged.

Things you need to add the feature.

  • 22 gage wire, about 6 feet.
  • Standard Phillips screwdriver.
  • Small Jeweler's screwdriver.
  • Soldering may be required.
  • 1/2 to 3 hours of time.
  • optional components:
    • momentary switch, extra batteries, drop cord?

Parallel Packs

I'm aware of a few other people who have added additional battery capacity to Prii, although they did not grid-recharge, those projects are rather close to becoming PHEV projects.

EV-Mode and your Warranty

Regarding your warranty

References

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