1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Disconnect the battery before doing mods?

Discussion in 'Gen 2 Prius Accessories & Modifications' started by paul.villasenor, Dec 13, 2006.

  1. paul.villasenor

    paul.villasenor Junior Member

    Joined:
    Sep 17, 2006
    25
    0
    0
    Vehicle:
    2007 Prius
    Model:
    N/A
    I apologize in advance if this question is as silly as it sounds, but do you disconnect the battery before adding any mods (EV switch, video interface, etc.) to your Prius? Is there a reason why you shouldn't? I'm only asking because my gut instinct is to disconnect it, but from what I've read here, it sounds like some people leave the battery connected. I didn't know if there was a reason specific to the Prius for keeping the battery connected.

    Thanks,
    Paul
     
  2. Presto

    Presto Has his homepage set to PC

    Joined:
    Mar 27, 2005
    1,326
    24
    0
    Location:
    Vancouver, BC
    Vehicle:
    2005 Prius
    The safe way to go would be to disconnect the Aux battery, but I like to live on the edge ;). The only bad thing that will happen if you disconnect is the time and MFD resetting. You'll have to set the time and your fuel consumption will be reset as well.
     
  3. Beryl Octet

    Beryl Octet New Member

    Joined:
    Aug 27, 2006
    1,293
    0
    0
    Location:
    Abingdon VA
    Vehicle:
    2005 Prius
    <div class='quotetop'>QUOTE(PaulV @ Dec 13 2006, 10:37 PM) [snapback]362003[/snapback]</div>
    I added an aux-in box to the stereo without disconnecting the battery. For an EV mode swtich, I'd probably disconnect it just to be on the safe side.
     
  4. eagle33199

    eagle33199 Platinum Member

    Joined:
    Mar 2, 2006
    5,122
    268
    0
    Location:
    Minnesota
    Vehicle:
    2015 Prius v wagon
    Model:
    Two
    It really depends on what you're doing and your knowledge level of electronics. If you're performing a simple mod that involves plugging/unplugging items, you probably don't need to worry about it. if it involves wire tapping, if you're sure the wire is electrically isolated or that you fully understand the implications have having it connected/disconnected at various times, then you don't need to worry about it.

    However, if you aren't that informed electrically about the car, then disconnect it just to be on the safe side. no harm, other than losing the clock, radio presets, and recorded mileage on the MFD, will come from it.
     
  5. aaf709

    aaf709 Ravenpaw of ThunderClan

    Joined:
    Apr 23, 2005
    3,862
    18
    0
    Location:
    San Diego, CA
    Vehicle:
    2022 Prius Prime
    Model:
    Limited
    I've installed Coastal's EV mod, Auto-Lock and basic NAV kit; cut and installed a switch for the phone override and installed the DICE all without disconnecting the battery. I was probably very luck, but there was no problems.
     
  6. Allannde

    Allannde Just a Senior

    Joined:
    Jan 7, 2006
    874
    138
    0
    Location:
    Washington State
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Advanced
    <div class='quotetop'>QUOTE(eagle33199 @ Dec 14 2006, 06:52 AM) [snapback]362119[/snapback]</div>
    The '06 Prius Repair Manuel specifies disconnecting the 12v battery for such things as replacement of the headlight even when the current is off to that component.

    When you diconnect the battery there is one more step (than those listed by eagle above) which you must do. It is initialization of the power window regulator. It is a simple procedure. After reconnecting the battery you: 1. turn on the car to Ready, 2. Open the driver's window half way, 3. Close the driver's window and hold it closed for at least one second, and 4. check theAUTO/UP and AUTO/DOWN to see that they work properly. If they don't, you disconnected the 12 v battery for 10 seconds and repeat the process.

    If you don't do this step, your power windows may not work properly.

    Almost any interuption of electric power calls for this initialization of power windows.
     
  7. eagle33199

    eagle33199 Platinum Member

    Joined:
    Mar 2, 2006
    5,122
    268
    0
    Location:
    Minnesota
    Vehicle:
    2015 Prius v wagon
    Model:
    Two
    <div class='quotetop'>QUOTE(Allannde @ Dec 14 2006, 10:02 AM) [snapback]362153[/snapback]</div>
    Never knew about that initialization... guess i've just been lucky :p

    And honestly, the only reason the repair manual specifies disconnecting the 12v battery for everything is for legal reasons - it's a hell of a lot easier to say disconnect it for everything than it is to fight a legal battle when someone leaves it connected and gets shocked when something shorts out (odds of that happening are slim, though)
     
  8. kDB

    kDB New Member

    Joined:
    Jun 22, 2005
    241
    0
    0
    Location:
    Fenton, MO
    When I installed my Kapppa's with an amp, I didn't disconnect the battery. I hacked together a T-harness to go between the stereo and the car wiring harness. I left one wire cut but untaped, wasn't stripped. When I plugged it in to see if it worked, pop, everything shut off..

    At first I though just a fuse, but nothing worked. No dome lights, car wouldn't start, nothing. After freaking out for a minute, I decided to start pulling fuses. Turns out I just blew one fuse, lucky me.

    I also accidentally bumped the windows lock switch when I was putting the driver door panel back on. Again took me a while to figure out why the passenger window switch would not work. Good thing I can keep calm pretty well.
     
  9. MPG > HP

    MPG > HP Junior Member

    Joined:
    Feb 26, 2006
    58
    0
    0
    Do you loose your calendar memos when you disconnect the battery? I ask, because that is where I've been logging my mileage.