6 volt in a 12 volt system
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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=73972
Printed Date: May 02, 2024 at 12:20 AM
Topic: 6 volt in a 12 volt system
Posted By: erv s
Subject: 6 volt in a 12 volt system
Date Posted: March 05, 2006 at 12:57 PM
hi all, i have been in and out of this site and have gotten a lot of help restoreing my 78 ford truck. now i have found some thing i am doing i can not find any where. i would like to put a 6 volt air horn in my truck but it is 12 volt. the horn draws 14 amps. anyone have any ideas? i could just put a battery in the bed but that takes up a lot of space, and keeping it charged right. thanks, erv
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78 Ford F250 4x4
old iron
Replies:
Posted By: Hoptup32
Date Posted: March 05, 2006 at 7:34 PM
Posted By: cvl
Date Posted: March 06, 2006 at 9:26 PM
Use ohms law to calculate the value of a resistor you can put inline of the power wire, there's not much else you need. your horns draw a fair amount, but I doubt you'll have to worry bout the resistors getting too hot.But that's only my $.02
Posted By: geepherder
Date Posted: March 07, 2006 at 6:47 AM
That's too much current to use a resistor. Why do you feel the need to use 6 volt horns?
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My ex once told me I have a perfect face for radio.
Posted By: erv s
Date Posted: March 07, 2006 at 4:08 PM
Just like the old school look of them. They came off of an old semi and would just like to get them to work on the 78 I have. It has 5 tones. Sounds really nice. I guess I will have to go with the battery in the bed and charge it with a switch and use a resistor to do that. Thanks, Erv
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78 Ford F250 4x4
old iron
Posted By: loneagle
Date Posted: March 08, 2006 at 6:07 PM
You could measure the resistance of the 6 volt unit, and put about the same value resistor in series with it to get voltage-drop from 12 to 6 volts; with power rating about 50 watts or so, as the horn shouldn't be operating more than a second or two...I hope. I use 50 to 100 watt audio load resistors at about 1 ohm for that current , or two 1 ohm units in parallell, if the drop is too much...sounds like fun playing with it... ------------- loneagle
Posted By: erv s
Date Posted: March 08, 2006 at 6:21 PM
loneagle, thanks, thats all i want to do is play. if you saw my truck you would understand. the wife just shakes her head. can i get these at radio shack? or can you give me a web site to get them. a part number would be great if you can. i can rewire a house or car but this kind of stuff is way passed me. wish i would have gotten into it more when i was young. if you would like to see my truck go to ford-trucks.com and look for my gallery.my user name there is ervin. Thanks again, erv
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78 Ford F250 4x4
old iron
Posted By: KPierson
Date Posted: March 08, 2006 at 8:13 PM
If you can figure out exactly how much current these horns draw at 6vdc you could build an inexpensive power supply that would run off of the 12vdc source. Also, do you have any more information on the horn itself? It would be interesting to know the absolute max voltage of the unit.
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Kevin Pierson
Posted By: erv s
Date Posted: March 08, 2006 at 8:37 PM
I ran it off of a battery charger and my meter read 14 amps. It is dated back in the 1950's some where, so I have no info or company name . Came off an old Mac. That 14 amps was under load so would that be a max reading? Is that some thing I would be able to biuld? And where would I fine a print or plan for something like that? Erv
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78 Ford F250 4x4
old iron
Posted By: KPierson
Date Posted: March 08, 2006 at 10:01 PM
14 amps is going to be a hefty power supply to build, but it can be done. I'm not sure how much effort you want to put in to this though! ------------- Kevin Pierson
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