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I need an always on power source in the car

Discussion in 'Gen 2 Prius Main Forum' started by DirkG, May 26, 2009.

  1. DirkG

    DirkG Junior Member

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    To save the $200 in installation fee that my local two-way radio shop wants, I will be installing a taxi meter myself.
    I talked to the guys at Centrodyne and it seems easy enough. Three wires. A black that needs to go to ground, a red that needs an always on connection, and a red that needs to hook up to pin 19 behind the glove box on the third grey connector. Thats a speed sensor, I havent looked at it yet, but he said its easy to find.
    So a couple of scotch locks, a fuse, and a lead to ground and I will be set with wiring.
    Are there any good spots, or should I just run the wires all the way back to the 12V battery?
     
    #1 DirkG, May 26, 2009
  2. ceric

    ceric New Member

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    Usually there is one inside the left side kick panel (next to your left foot when driving).
    Use a tri-meter to test for one or get a wiring manual.
    Watch out for current draw to avoid overloading the fuse.
     
    #2 ceric, May 26, 2009
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  3. firepa63

    firepa63 Former Prius Owner

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    You do recognize that having a load constantly on the 12v system will run your small 12v battery down in no time?
     
    #3 firepa63, May 26, 2009
  4. DirkG

    DirkG Junior Member

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    I guess I could wind up my meter like a clock then? Or just guess at what the fare and waiting time should be. Oh I know I will use a solar cell, and just not go through any tunnels or work after dark.
    :rolleyes:
     
    #4 DirkG, May 26, 2009
  5. DirkG

    DirkG Junior Member

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    I'll search for an online wiring manual, it will be better if there is one on the right side where the other wires are going. When it gets back from being painted I guess I will tear the dash up to route the wires and check the kick's for always hot wires.
     
    #5 DirkG, May 26, 2009
  6. firepa63

    firepa63 Former Prius Owner

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    There's not a problem when in the READY mode, but there will be when the car is off and the load remains on the 12v battery.
     
    #6 firepa63, May 26, 2009
  7. richard schumacher

    richard schumacher shortbus driver

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    A taxi is always ON anyway whenever you need the meter, right? So draining the 12V battery will not be an issue.
     
    #7 richard schumacher, May 26, 2009
  8. DirkG

    DirkG Junior Member

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    Close, the taxi is almost always on. When I am waiting at a store, or someplace while my fare is inside, the car is off but the meter is still running. Draining the 12v battery is not an issue, cars have had taxi meters in them for decades. They are always wired to constant power. The meters shut off after a few minutes and go into standby if they are not on wait time. You can leave a car off for weeks at a time and the meter wont drain enough of the battery while its in standby to keep the car from starting. The dashboard clock uses more power.
     
    #8 DirkG, May 26, 2009
  9. richard schumacher

    richard schumacher shortbus driver

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    The 1 amp or so drawn by the dome light can drain a Prius battery in a few hours (it's really wimpy), but it sounds like the meter would never be in such a high-current state for very long when the car is OFF.
     
    #9 richard schumacher, May 26, 2009
  10. David Beale

    David Beale Senior Member

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    I think you have two choices, either directly from the 12V battery (inline fuse at the battery), or from the drivers side kick panel. In that fuse box you will find an interior lamp fuse, 25A rating. If you decide on that for a source, you could use a "fuse tapper", a brass strap you slip over a fuse leg and then plug the fuse back in. You use a 1/4" push-on terminal on the "fuse tapper". These devices -can- cause problems, as they tend to spread the fuse socket a bit, and over time can cause intermittents once removed.

    My choice was the battery with an in-line fuse for my amateur radio. You can then use your creativity when you run the cable to the front of the car. ;) I ran it beside the "transmission hump" in a piece of plastic loom (under the carpet -inside- the car).
     
    #10 David Beale, May 26, 2009
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  11. DirkG

    DirkG Junior Member

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    I dont know the draw once the meter is in standby, less than the clock or an aftermarket stereo. If it turns into a problem while the car sits for 2 days on my days off, then I have a spare Red Top that I can put in the stocks battery place. It looks like all I need to do it replace the cable connectors with something bigger, I saw a right up on a Yellow Top conversion but I dont need the battery just the connectors.
     
    #11 DirkG, May 26, 2009
  12. David Beale

    David Beale Senior Member

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    Unfortunately a "standard size" (Optima for example) battery won't fit in the Prius battery space. The replacement Optima is a small battery (I think it's a size used by Honda Civics, which are often used as a base for a show car). The problem is width. The Prius space is about 1" too narrow. It -may- be possible to raise the battery by making a spacer to sit it on so there is more width (the space tapers wider with height), but then you would have to deal with re-engineering the fusible link holder etc as well as the battery holddowns.

    I don't think there will be a problem with the battery and the meter, as there are hundreds of Prius Taxi' on the roads, and I doubt -any- of them have modified 12V battery systems.
     
    #12 David Beale, May 27, 2009
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