12 volt conversion

[katy]

I tried a voltage reduction device from speedway & it was too much of a drop in voltage, it would work fine on a constant load but not the horn

You could try 2 of them in parallel.

[Mike V. Florida]

I goofed on the ohms law, it is early in the morning. Don't tell my boss, wait I have a union job never mind.

Let me see if I can explain this another way. My house has a 200 amp service going to it. This does not mean that I draw 200 amps. A car can have a 100 Amp alternator but the car will not draw 100 amps just because of the alt.

If the battery is run down to the point that it will accept 90 amps it would not start the car in the first place and the battery would most likely explode, if the main fuse that almost every A owner has installed, did not blow first.

I have never heard of this happening if you have can you cite a source. Nobody in our car club that has a 6 volt alternator has a 30 amp meter in it and none have burned up.

It is your car to do whatever you want to it. If it gets you on the road fine do it.
I'm just saying that unless you are going to add accessories to draw more than 20 amps the amp meter can stay and you can use the money saved on gas to keep you on the road (besides you would need to calibrate the wire you would use as a shunt to properly divide the current if you went in that direction).

The started can no way push off the gear ring as the system is designed.

Again to be crystal clear it is your car do with it as you want, my objection is that someone will make the choices based not on personal preference but on wrong information and even cause damage.

[pinball73]

Originally Posted by BillLee/Chandler, TX

https://www.brattons.com/horn-resistor.html

Thanks guys! I got to have one! been looking for a long time

[30 Closed Cab PU]

Originally Posted by Badpuppy

With a 12V conversion you should expect half the normal current reading as the 6V. If you add electrical accessories such as AC clutch and blower fans or - Lord save us - electric heaters, you should bypass the ammeter with properly sized wire.

An ammeter should not overheat within its dial range. If it does, the cause is faulty connections either internal or external. Wire terminals should be soldered for best connection. Those hardware store crimpers really don't do it.

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[30 Closed Cab PU]

Originally Posted by Badpuppy

With a 12V conversion you should expect half the normal current reading as the 6V. If you add electrical accessories such as AC clutch and blower fans or - Lord save us - electric heaters, you should bypass the ammeter with properly sized wire.

An ammeter should not overheat within its dial range. If it does, the cause is faulty connections either internal or external. Wire terminals should be soldered for best connection. Those hardware store crimpers really don't do it.

I believe the current is the same, 6 or 12v.


When converting from 6 to 12, all the loads (coil, starter, lamps, wipers, etc.) have to be updated with 12 V components, or a Series limiting resistor installed on the 6V part.


Essentially; the 12v replacement has twice the resistance of the 6v part, or the series limiting resistor is sized the same as the 6V part and when put in line with the 6V part doubles the resistance of the 6V part for 12 v operation. Eitherway, way current is same: 6V part on 6V, 6v part with series limiting resistor on 12 V, or a 12 volt part on 12V.


An ammeter shunt is only needed when using alternators. They can deliver a max of current of 80-90 amps, pegging a 20 or 30 amp max ammeter. High readings can happen if the alternator is not regulated. Case of high output - short time after starting until the battery refreshes from starting. Longer high output - a partially discharged or bad battery, Halogen lights, lots of optional lights (cowl, fog, etch), air conditioning, etc. A properly shunted ammeter halves the current going through it, and you have to double the reading in your head to get a true reading.


For a long time I had difficulty getting my head around all this, info was spread out and I am not as quick as I once was learning/understanding all this new to me info.

[katy]

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Eitherway, way current is same: 6V part on 6V, 6v part with series limiting resistor on 12 V, or a 12 volt part on 12V.

Not true, when on 12 volt the current (amps) will be 1/2 of the current for a similar part on 6 volt.
If you have a 12 volt 50 watt bulb on 12 volts it will draw around 4 amps.
If you have a 6 volt 50 watt bulb on 6 volts it will draw around 8 amps.
Watts law, watts equals the voltage multiplied by the current in amperes.

[Badpuppy]

^^What katy said. And the resistance of a 12V bulb is 4x that of a 6V of the same wattage: W/V = A, V/A =R. From katy's example, 12/4 = 3; 6/8 = .75.

If you add a series resistor with a device with the same resistance (horn motor) the power dissipation is doubled, since the current must remain the same. The resistor dissipates the same power as the horn in heat, rather than honking.

[Charlie Stephens]

The problem is not the discharge side (unless there have been a lot of changes) but the charge side.

Charlie Stephens

[MAG]

From Post 42.
"The started can no way push off the gear ring as the system is designed."

Are you really sure about that?

[30 Closed Cab PU]

Originally Posted by Badpuppy

^^What katy said. And the resistance of a 12V bulb is 4x that of a 6V of the same wattage: W/V = A, V/A =R. From katy's example, 12/4 = 3; 6/8 = .75.

If you add a series resistor with a device with the same resistance (horn motor) the power dissipation is doubled, since the current must remain the same. The resistor dissipates the same power as the horn in heat, rather than honking.

I see on your public profile you are a retired EE, so either I am having issues remembering theory learned 45 years ago and not used in depth since then(definite possibility), or we misunderstand each other. If fOK with you I will be looking at this more in the next few days, and PMing you - take this off line until I understand. Thanks for being patient, am just trying to understand.

[The Master Cylinder]

I enjoy these long drawn out threads that go way off topic but that is a good thing because maybe I will learn something (or become confused by incorrect info).

Unfortunately the OP has not been back for ~1 week so he can't take advantage of the same...

[30 Closed Cab PU]

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Deleted, not sure my calculations used correct coil resistances.

[30 Closed Cab PU]

I have not done the conversion from 6v to 12v , so it is all theoretical. How about getting feedback from member's who have done the conversion. Did current at the Ammeter increase or decrease substantially, or stay about the same?

[Kurt in NJ]

Originally Posted by MAG

From Post 42.
"The started can no way push off the gear ring as the system is designed."

Are you really sure about that?

"as designed" means the ledge on the flywheel is still there , not broke/ worn off due to improper ring gear removal, and a ring gear that fits properly with the proper shrink, and tooth geometry

[MAG]

The ring gear is installed on the flywheel.. front- to- rear. Meaning, with the flywheel lying with the clutch side down, the ring is installed the top side. Pushed on until it reaches the ledge. It is held in place by friction/fit. The starter drive engages the ring gear from the back side. In effect trying to push the ring gear forward; i.e. toward the engine. The starter engaging force is opposite to the installation force.
Saw 3 cases of it last year.
One came completely off.
One came forward enough to cause a severe knocking. The ring gear teeth were hitting the webbing inside the flywheel housing. Drove it back on with a punch and tack welded it in place around the perimeter.
The third one was mine. I noticed it when the starter was removed for 12v conversion.
My ring gear was a new repo. that I installed when rebuilding the engine some 12K miles ago.
Do not know about the other two ring gears.

[jrelliott]

As stated before, running 12V conversion with original power house generator. Had a 12V alternator at first, then went back to 6Volts when I found the Power House. Went back to 12V as easier to find batteries here in the sticks. Wanted a 12V regulator, but Tom Westburg only has a 6V one. I am designing my own and now have the parts to build and test it. Wanted one that went inside the generator to control the field and not like Fun Projects which regulates the current and Voltage afterward.