Electrical question

Discussion in 'The Bench' started by V8Adam, Jan 29, 2020.

  1. V8Adam

    V8Adam Well-Known Member

    Hey everybody,
    I am looking to add one of these to the trunk of my 1972 Buick Riviera. Do you guys have any recommendations on where to take the power from? I was thinking of running an in-line fuse in the cable.
     
  2. GraySky

    GraySky Well-Known Member

    Add one of what?
     
  3. V8Adam

    V8Adam Well-Known Member

  4. 72gs4spd

    72gs4spd Well-Known Member

    First would need to know power rating as in amps. If could be wire into a switched source at the fuse box with a inline fuse at the box if it’s lower amperage than the terminal can endure.
     
  5. V8Adam

    V8Adam Well-Known Member

    Thanks for the reply. In terms of amps:
    USB ports only usually go up to 2A, so that would be 4A.
    The voltage meter is 16ma I believe.
    The 12v socket, the device I want to use draws 3.5A, so I was thinking 5A to be on the safe side.

    So in total, 10A should do it. What do you think?
     
  6. GraySky

    GraySky Well-Known Member

    I would use 18 or 20 awg wire, and a 5A slow fuse inline as close to the takeoff point as possible. Make sure adding 5A to wherever you're tapping into will not overload that circuit, or go right to the battery and fuse at the battery.
     
  7. GraySky

    GraySky Well-Known Member

    If you want the full 20A capacity of the outlet, you're going to need 12 awg wire and a 20A fuse. I would definitely take that off the battery.
    Not sure where you're getting 10A from.
    USB ports likely have a switching converter so that 2A at 5 volts is actually somewhat less on the 12V line.
     
    bhambulldog likes this.
  8. TrunkMonkey

    TrunkMonkey Well-Known Member

    Maybe a 20A "resetting circuit breaker", preferable to fuse.
    upload_2020-1-29_14-30-10.png
     
  9. Daves69

    Daves69 Too many cars too work on

    You have a 72 Riviera with cigarette lighters in the back seat ashtrays. I would remove the back seat and tap into the existing wire, and route it to where you want to place the outlet in the trunk.
     
  10. V8Adam

    V8Adam Well-Known Member

    Unfortunately I do not have cigarette lighters in my rear ashtrays. I am guessing that these were only available with power windows?
     
  11. bhambulldog

    bhambulldog 1955 76-RoadmasterRiviera

    I would do it this way,
    When adding after market components , I'e done it this way
     
  12. BUICKRAT

    BUICKRAT Got any treats?

    There should be an extra terminal in the fuse box, usually labeled as accs, that you can tap from. Make sure it is fused, they usually are. Should be 15 amps or more, some are 20. If it's not fused, use an inline fuse as close to the fusebox as you can.
     
    GraySky likes this.
  13. V8Adam

    V8Adam Well-Known Member

    Thanks for your advice guys, really appreciate it as always. I will look for the extra terminal Steve.
     
  14. V8Adam

    V8Adam Well-Known Member

    Just a follow up question. My Buick does not have the rear window defogger. It does however, appear to have the cabling in place and presumably the fuse.

    Could I use this wiring? I looked in the workshop manual but couldn’t find what amp rating the fuse/cable was.
     
  15. Mark Demko

    Mark Demko Well-Known Member

    Maybe, how heavy, gauge wise is the wiring?
    I know these older cars up thru '76 used HEAVY gauge wiring for high amp draw circuits, like electric grid defogger.
     
  16. jay3000

    jay3000 RIP 1-16-21

    No. Your only way to run power to the rear is to start from the battery. Use a 12 GA or larger wire with a 15A fuse right at the battery. It will be live all of the time.
     
    Mark Demko and bhambulldog like this.
  17. V8Adam

    V8Adam Well-Known Member

    Thanks for the replies. I don't know the current gauge, is there a way of finding out?
     
  18. BBBPat

    BBBPat Well-Known Member

    Last edited: Feb 11, 2020
  19. V8Adam

    V8Adam Well-Known Member

    Ah fantastic, thank you!

    Jay3000, I understand what you're saying, I just wanted to only run a new cable run if I had to. Is there a particular reason you would not use an existing cable or is it mainly to do with cable age etc?
     
  20. HotRodRivi

    HotRodRivi Tomahawks sighted overseas

    I would just get an amp wire kit. Just the big red wire with an in line fat glass fuse thats designed to reach the trunk. Use some of them yellow nylon connectors. Make sure you wear ansi aporoved goggles, eye protection, gloves, a helmut, and have a bucket of water or fire extinguisher handy. If you live in CA.
     

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