Hey all, Putting a 6V horn on a 12V system. I'd like to run a regulator to reduce the voltage, but unsure of how much current to plan for. Anyone have any measurements? I've got a old Chevy ohagah horn and an unknown 3 trumpet. I'm pretty sure I'll be figuring this out myself, but just in case anyone has had time before me...
Be sure to use a relay. Don't worry about the voltage situation. Six volt horns are very loud on 12, that being about the only difference.
On 6v, many originals draw up to 15 amps. They do work OK on 12v, and I've had no problem with the 6v relay but I don't use the horn a lot either. I had to adjust the tone with the screw on the points at the horn coil. The coil vibrates too fast on 12v, sounded like a foreign car
I did hook the horns up to 12 just to make sure they worked, the awoga was a little high pitched, but the trumpets just went off too quick I want to slow them down some to make them sound original. I've seen where people are using ballast resistors to reduce the current / voltage, might toy around with them. Just wish I had a adj. power supply capable of my projects..
Thats called a rheostat. A adjustable ballast resistor. Available in ranges from micro amps to mega amps. With a 12v supply, you can adjust your Aahogaa horn to do anything from a low groan to siren pitch anytime you want to and dial the trumpets to a perfect pitch. A relay is an excellent idea for any horn. Your aahogaa is going to draw between 14 and 20 amps and about 10 for each of the trumpets. Just a point- If you install a rehostat, put it where it has good airflow around it and is not against anything flammable. They do put out a fair amount of heat.
I run my 6volt trumpets on 12 volts, have for years with no problems. Best relay I've found is old style Chrysler starter relays.
found on another site: "You'll need to measure the resistance of the horn itself, and use a resistor of about that magnitude. The rating of the resistor should be in watts; to convert, use 36/R, where R is the resistance in ohms. Find a resistor at least twice this rating to be safe." "36 is V*V, where V is the Voltage across the resistor. By putting in a resistor that has the same voltage drop as the horn, you drop the 12V down to 6V when current flows to the horn. Since you want a 6V drop, V*V = 36. "
I just run 12 through my 6V horns. But you have horns that are supposed to make a certain pich right? Mine are just to p*** inspection. You need to get a resistor that will drop your voltage from 12 V to 6V. You can get one at any reputable auto parts store. Fine one with someone that can read and understand english and explain what you want to do. The resistor will go between your voltage source and the horn relay. If you go between the relay and the horn you'll need a really tough resistor or you will quickly burn the resistor out.
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