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How big of a fuse can I use in the add-a-circuit under the dash?

Discussion in '2nd Gen. Tacomas (2005-2015)' started by iroc409, Nov 20, 2011.

  1. Nov 20, 2011 at 4:23 PM
    #1
    iroc409

    iroc409 [OP] Well-Known Member

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    I am currently using an add-a-circuit in the under-dash fuse block on the driver’s side. I’ve only had a 2A fuse on it, just for a couple relays, but I’d like to add a couple things to the circuit.

    I think I would go to 7.5-10A on the circuit. The fuse spot I am using is the blank one that comes on with the ignition (I only use one fuse on the add-a-circuit so I don’t connect whatever it isn’t connecting).

    I don’t know that I would be using that much power. I am going to run 2-3 relays, a couple LEDs, and a power supply for a oil pressure & temperature sending units (AeroForce). It says it needs a 5A circuit, but I don’t know what it actually uses. I might be able to get away with only 5A for everything. Relays and LEDs don’t use much.

    I am willing to run a separate circuit and relay if need be, but no reason to do that if it’s OK.
     
  2. Nov 20, 2011 at 5:30 PM
    #2
    muisejt

    muisejt Well-Known Member

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    the add a circuit I have says 10A max
     
  3. Nov 20, 2011 at 5:39 PM
    #3
    rcbs204

    rcbs204 Well-Known Member Vendor

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    10Amps then, unless you want a fire.
    Edit: Opps read the guys post above. The mfg alway over rate there stuff for a safety factor.
    I would use a 4 amp fuse. if it blow which i doubt it will, then bump it to a 5 amp. Always want to be under the max rating.
    Edit #2: LEDs usually only pull 25ma each. Relays on the other hand, can pull an 1amp depending on the coil.
     
  4. Nov 21, 2011 at 10:52 AM
    #4
    iroc409

    iroc409 [OP] Well-Known Member

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    I found after I posted the add-a-circuit is 10A maximum. I don't think these relays pull much at all, but I can't remember the spec. It could probably run along with the 5A circuit for the little power supply.

    I guess maybe I should just run the circuit then, and stick with the 2A in the add-on, which will just power the ignition-hot circuit relay. I've been running 2 relays on the 2A circuit no problem. I was also trying to reduce the amount of wires running through the firewall, as I have a limited space to run things.

    I guess I should see if I can run the power supply underhood. It looks mostly sealed (heatshrink), maybe I can find a little box for it. I'll just have to look up the heat ratings. It will also help not having to run the whole set of sender wires through the firewall, only the signal wire.

    ETA: The power supply only requires a 2-3A fuse, with their drawings showing 2A power supply. So, a 3-4A fuse should work OK (and the power supply should be mounted inside). So, that should work OK.
     
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