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Quartz headlights

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  • Electrical: Quartz headlights

    I have a set of Bosch headlights that use the H4 quartz bulbs and they have 6-volt bulbs in them. Is the stock '51 headlight switch robust enough to handle the extra current the bulbs will draw, or should I install a relay to send current to the lights.

    I'm sure I'll end up with LED bulbs at some point, and I know they draw much less current, but I'm still curious to know what others have experienced using H4 headlights. I have a fresh headlight wiring harness from the Rhode Island folks, so the wiring at the lights shouldn't be an issue. Thanks.

  • #2
    My 12v ones draw 55 or so watts each, about 10 amps in your system. I know 6 volt wiring is heavier than 12 v but I'd add the relay. JMO, Bob


    • #3
      What Bob said. It's not the wiring that's the problem -- it's the switch that will get hot and fail. Don't install halogen headlights without a relay.
      Skip Lackie


      • #4
        Is there such a thing as a relay that will work with both six and 12-volt electrical systems, or am I dreaming? Thanks.


        • #5
          There might be some 12 volt relays that will pull in, if fed six volts, and there might be some six volt relays that will last a long time when fed twelve volts, but I don't think there are any specifically sold as six volt/twelve volt relays. But six volt, and twelve volt "dual headlight relays" are readily available, or at least used to be. Two relays in one box, one for high beams, one for low beams.And a relay coil is probably one instance where you could use a voltage-dropping resistor successfully to operate a six-volt component on a twelve volt supply.
          Gord Richmond, within Weasel range of the Alberta Badlands


          • #6
            Plenty of 6-volt relays around, look on the Porsche 356 sites...
            Last edited by ralt12; 06-04-2019, 11:31 AM.
            '53 Commander
            Art Morrison chassis
            LS6 ASA/4L60E


            • #7
              1948 M15A-20 Flatbed Truck Rescue
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