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Power tapping for 12v stuff?

Discussion in 'Modifications and Projects' started by Teamsherman, Jun 20, 2013.

  1. Hey folks,

    Im on a 2003 Kawasaki Z1000 so im guessing the answers to my question will be different all round, but in a general consensus, where do most of you tap power from to run your GPS' and mobile phone plugs ect?? Im getting a fancy holder for my iPhone and want to be able to power it while i ride. Im thinking of buying a cigarette style plug from BIAS boating and installing that just tucked in under my little screen, and tapping the power from the rear of the headlight. Reckon that will work??
  2. In my bikes I have used a cigarette socket wired directly to the battery, via a fuse. I have done this as I want to be able to use the power out without the bike being powered on. The vstrom has the socket under the seat on a lead long enough to be useful, but the vstar has it just under the removable side panel on a short lead.

    Under the screen would be useful if you want it for GPS or such like. I tend to ride until I'm lost, so I don't bother with one.
  3. My bike is only 300cc and I have my strike GPS wired to my front indicator (dedicated charger/cradle) and I put a cig style USB (2 connections) in my tail bag (tiny hole in bottom of bag, wire runs under seat) which is attached to my rear indicator.

    No dramas to date (have charged 2 phones and the GPS at the same time) so I'd think you could have even more hooked up with a more powerful bike.
  4. :ROFLMAO:
    Don't tell me
    " it works
    no it doesn't
    yes it does
    no it doesn't"

    Usually the easist to pick up under the seat is the tail light, switched with ignition and fused around 5A so can comfortably carry chargers for phones/GPS etc and still protect them ;)
    Headlight usually is 15 or 25A fuse and heavier wiring to attach to
    • Funny Funny x 1

  5. So are you saying the power doesn't run through the wires when the indicator is not in use? If so, I best get this checked as I have power to both the navigator and USB port as soon as I turn my bike on.
  6. Most new bikes now have permanent (ignition switched) power to circuits and then switch the erath off to activate them. Blinker ccts can be fraught with problems for powering things IF you get the wrong part of the cct.
    I was just being silly with the "works/doesn't" like you'd picked up the blink of the blinkers :D .
    A BIG hint for anyone picking up ignition switched power is to check with a test light rather than a multimeter, so it puts a load on the cct. There are a few ccts for diagnostics that will show 12V with a meter but cant supply a load.
  7. As an Electrical Engineer (No not like Wally from Dilbert, I'm much taller) and rewired automotive stuff for too many decades, MAdAzz sorry it don't. Electricity basics: Current runs around a loop. Indicator is a single light globe with one wire going in and another going out. When light is lit, current flows, when light is dark, no current at all. Indicators work by turning power on and off, then stay off. Digital meter on an a blinking indicator will gives numbers all over the shop never settling on a constant reading. Analogue meter (old fashioned needle) will regularly flick in time with blinks.

    Ducfreak is right, with earth disconnected to turn the blinker off there is not a good reference and you can measure a "floating" voltage. May measure 12V but can't supply much if any any current. Phone with GPS running draws around 1 amp. or the same as a 12W light globe.

    There may be enough current for phone or GPS to detect 12V and show that it is "charging" but the device will slowly go flat. If your bike is wired so that the headlight is on when ignition is on, move the power tap to the headlight.

    Confused you? Sorry.
  8. And another thing. Don't have a multimeter? Simple & cheap test device is the globe out of the indicator - they are usually 10 to 12 W if they are they old filament type - not modern LED. Couple of wires on the bottom of the globe and put it across the point you want to test. if it is as bright as a working indicator - you've got volts.

    Premade one, $10 test lamp from Supercheap:


    Which is basically a screwdriver with a globe built in and a wire on the handle. Put the clip on one terminal and touch the point of the screwdriver to the other terminal you want to test and it lights up if there is volts.

    Or... Appeal to some helpful NetRider from near "Lower Blue Mountains" for a little weekend tinkering.
  9. Are you guys sure that the indicator doesn't have a constant 12v supply and then switches the ground to complete the circuit?
    • Agree Agree x 1
  10. Confused? No mate...I reckon there's a few working cells floating around my brain somewhere. ;)

    Thanks for the info.
  11. would need to go throught he cct diagram for the actual bike to be 100%
    Depends on how it was designed
  12. No, not sure. Good Point. Could well be the case. Have to be sure you take positive from right side of globe though. Dimly glowing indicator would tell you.

    But why bother? If you've got a headlight that's on when running, you know you've got power and the cct can take the load.

    Just checked my Yamaha YZf-R15, negative earth (I know that's irrelevant). Does have transistorised flasher relay, but is load sensing.

    Which does bring up another point - extra load of GPS/phone on flasher cct.

    MadAzz. Load Sensing means that flasher relays have a way to tell you if a globe has burnt out, the flash rate is based on how much current the globes drain. If a globe burns out or you replace one with the wrong wattage, the flashing rate will either be very quick or painfully slow. The flasher relay would detect a GPS as an extra high wattage globe and the flash rate would change. You could test this by removing one of you indicator globes and turn the indicator on. If the rate does change, then you have a load sensing flasher relay. If you do, then turn it all off. Put the globe back. Start the bike turn the indicators on plug the GPS in & turn it on. If the flash rate changes, then the GPS is getting power only when the indicators are working.

    Hang on. MAdAzz does the GPS have batteries? i.e. does it work when not in the cradle?
  13. I didn't install these gadgets, they were done by a bike shop. I asked where they hooked everything up and I was told the indicators. That could have been an off the cuff comment because I'm a chick who must not know anything about bikes. Now that I have this info, I'll check where they actually hooked in over the weekend.

    The GPS unit has battery back up, but I did drain the sucker of all power before I put it on the bike. 4hrs into my ride saw it fully charged, so obviously it does get constant power.

    The power port has a blue LED on it, which would drain my battery over time if it was hardwired to that, so it too is spliced in somewhere. I'll let ya know where when I know.

    As for:
    That makes me chuckle, considering I just got one of my mates bike up and running cause he didn't have a clue what was wrong ;)
  14. Well that settles that. Well stuff me. :bag: Must be as Ducfreak said a positive earth with connection to ground to activate lights.

    If you could be bothered, next time you have the GPS start the indicators and try plugging in and unplugging the GPS to see if flash rate changes.

    As an aside I brought a cheap cigarette lighter USB adapter to run the Android phone GPS. Over 2 hours would slowly go flat. USB only put out 1/2A. got a 1A adapter and it would charge up.
  15. No No No, there isa positive supply to the blinker unit, then to the switch,
    once selected which blinker (by the switch), cct completes vis the appropriate globes (in parrallel) and the load causes the blinker unit to "blink".

    had the shop connected on the outgoing side of the switch then we get
    " it works"
    "no it doesnt"
    " it works"
    "no it doesnt"
    " it works"
    "no it doesnt"
    " it works"
    "no it doesnt"
    " it works"
    "no it doesnt"
    " it works"
    "no it doesnt"
    " it works"
    "no it doesnt"
    " it works"
    "no it doesnt"

    but its connected on the permanaent supply to the blinker unit ;) So all is good
  16. For a while I used a generic 12 volt power supply linked to the battery. It was just hanging loosely in my LH fairing pocket but in the last couple of months I upgraded to a waterproof dual socket attached to a dash shelf that I had just bought.

    Socket wiring includes the fuse (15 amp) and is connected to the battery so it's on all the time.
  17. Doh. Yes . Not Positive earth, we do have some of them here at work. Blue & Red bus-bars. D.C. but hollow, go figure.
  18. I checked my blinkers just now, with phone and GPS connected, then took them off and the blink rate didn't change..sooo.. do I take my bike apart to look where the things are connected, or not worry?
  19. LOL
    Just leave it all is good :)
    • Like Like x 1
  20. #20 Wil02, Jun 21, 2013
    Last edited: Jun 21, 2013

    Sounds like it will work to me.

    I used a relay off the tail light to power a completely separate circuit from the battery but that was possibly overkill.

    I have one of these on the handlebars ... has 2 usb sockets.