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Need 12v dropped to 6v for my old dodge truck heater blower
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Author:  radarsonwheels [ Tue Nov 16, 2010 11:02 am ]
Post subject:  Need 12v dropped to 6v for my old dodge truck heater blower
Sorry for the '50s question, but it is a mopar straight 6! ;)
(c-series 3/4 ton pickup, 230cid flathead 3 on the tree)

I put a 12v generator in my old 6v truck. The last thing to get switched over is the heater box. The original one is still in there. It says mopar on it, isn't rusted out, doesn't leak antifreeze, and the electric motor worked a couple years ago when the truck was 6v. It is a really cool piece and I want to keep it.

I need to set this thing up to run the fan. It has one wire and grounds to the mount. Can I run a switch to the fan through a 1ohm ballast resistor from a dart? How well would that work? I saw voltage drops for sale on ebay for this purpose and they were listed as 1ohm, so I thought about how I already have a few 2 pole ballasts floating around as spares.

Is there a slicker and still inexpensive way to do this? If so where would I get the parts? Can I easily run a three position switch (would have to be a twist knob) or potentiometer? Maybe even a house lightswitch dressed up with an old knob? Where can I frugally source decent quality parts?

I don't have streetrod catalog money right now, and it will soon be a little cold to drive with no heat.

I've done some wiring but when it gets into ohms etc. I know just enough to be dangerous.

Thanks!
Kevin
Author:  carlherrnstein [ Tue Nov 16, 2010 3:58 pm ]
Post subject: 
You might be able to use ballast resistors to drop the voltage but I would think that you would have to put them in sets that are in series to get the right voltage then put a few sets in parallel to handel the current. I would get a commercial voltage drop.
Author:  GTS225 [ Tue Nov 16, 2010 5:46 pm ]
Post subject: 
How about checking out those resistor networks for multi-speed automotive blowers? You know.....the resistors that mount in the heating duct and use airflow to keep them cool enough to not burn out.
Seems to me that one of those should handle the current that the 6vdc fan would be pulling.
The other possibility is a salvage yard search for a 12 volt fan motor that you can adapt to the older housing.

Roger
Author:  radarsonwheels [ Wed Nov 17, 2010 5:00 am ]
Post subject:  Thanks
Thanks

For the good ideas.
Author:  66aCUDA [ Wed Nov 17, 2010 7:01 am ]
Post subject: 
Be careful!!! Was your old wiring POSITIVE ground? Is your New wiring Positive ground. I converted an old truck to 12volt and went from positive to negative ground and you cant combine the two systems easily.
Frank
Author:  lancer61 [ Wed Nov 17, 2010 11:12 pm ]
Post subject: 
If you have two ballast resistors you can make a voltage divider (for 6 volt they should have the same resistance).

http://www.raltron.com/cust/tools/voltage_divider.asp
Author:  radarsonwheels [ Thu Nov 18, 2010 10:27 am ]
Post subject:  results
First thanks again for the help with the somewhat off topic post.

I found out the dart ignition style ballast works great...

for about ten minutes, then it overheated and failed. The fan motor obviously draws too much juice for the little element to convert 1/2 to heat and still live. Oh well. I went for the flat plastic wrench with the numbers and magnetic strip on it and bought a voltage reducer off ebay specifically for this app. Thanks again for the ideas. I guess I'm not cut out to be a shadetree electrical engineer.

PS: it is now neg. ground. I once wired a pos. ground triumph motorcycle- as simple as it is it still made my brain hurt for some reason. Stupid british lucas parts...

vroom vroom!

radar
Author:  phogroian [ Fri Nov 26, 2010 8:39 am ]
Post subject: 
How about wiring two 6V batteries in series instead of using a 12 volt car battery? For the 6V applications you could center tap the battery rig.
Author:  Mirdbird [ Sun Jan 30, 2011 4:14 am ]
Post subject:  Ah the Marine
Quote:
How about wiring two 6V batteries in series instead of using a 12 volt car battery? For the 6V applications you could center tap the battery rig.
Affirmitory marine...
Author:  Charrlie_S [ Sun Jan 30, 2011 5:46 am ]
Post subject: 
Quote:
How about wiring two 6V batteries in series instead of using a 12 volt car battery? For the 6V applications you could center tap the battery rig.
How would you go about getting equal charge in both batteries?

How about a solid state voltage dropping device? Something like the solid state instrument regulators, but with a larger capacity.

Here is something.
http://www.speedwaymotors.com/Voltage-R ... layId=2374
Author:  SlantSixDan [ Sun Jan 30, 2011 12:20 pm ]
Post subject: 
Almost certainly easier and less expensive to replace the 6v motor with a 12v one, or have an electric motor shop rewind the existing motor for 12v service.
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