Here is my problem men,

I have a 53 f100 with the flathead, truck is still 6 volt positive ground. I am using a newer 8 volt battery. Truck has been running good however when I filled up at the gas station, the battery was dead and wouldn't start. I plan to see if the generator is bad by checking to see what the battery is at with my volt meter while the truck is running. I would think if the generator is good the volts at the battery should be around 9 volts at idle.

I read on another forum that my voltage regulator setting needs to be set at 9 volts to properly charge the 8 volt battery. Is this correct?

 

An eight volt battery is generally considered a patch at best. A six volt generator will not charge an eight volt battery. A generator puts out very little or nothing at idle. You may find someone to adjust the regulator to where it almost works. Good luck on finding someone today who knows how a regulator works. If it were mine, I would put a six volt battery in it and make sure the generator and regulator are working as designed. Six volts works quite well if right

 

I second the 6 volt battery. Almost all 8 volt battery installations I have seen ended with a dead generator and or regulator.

 

If you get yourself a reprint of the original repair manual it will tell you the step by step process of adjusting your regulator. However, you need to have a regulator that the cap can be removed. Some come with rivets so they are nor easily removed.

Ditto on the 8V battery. Your generator would have to be in pretty good shape to put out the 9.2 volts needed to recharge the 8v battery. Good luck, Jag

 

Actually the 6v gen's can be used with an appropriate regulator to provide 12v, with a reduction in maximum current. It was pretty commonly done. You can also simply use parts from a Y-block generator. But the 8v system as stated solves no problems and creates others.

 

Well...back to your original question...do you have a generator problem or a regulator problem?

You can test the generator by temporarily disconnecting the generator field connection, and momentarily jumping the field lead to the battery negative terminal (positive ground right??).

While you do that, have your voltmeter connected to the battery. If the voltage increases, the generator is working. You'll have to have it running at a high enough RPM for the generator to produce power. If that happens it is telling you that you have a regulator problem. If there is no voltage increase, it can be a couple of things: 1. the generator is broken (or has a failed brush); 2. you didn't have it at a high enough RPM, or; 3. The internal magnets have lost their magnetism and you need to flash the field. If a generator sits for a long period of time without producing any current, the magnets can go flat. Get the manual out, because some say to motorize the generator...take off the belt and apply power (negative battery) to the field and let the generator turn like a motor. The magnets will once again become magnets.

On the 8v thing....battery cells generally have 2.2 volts per cell (or 2.1 depending on which textbook you read). Your 3 cell "6v" battery is actually a 6.6 volt battery. The generator has to charge at something higher than that to make current go into the battery, so probably around 6.9 or 7 volts. The 8v battery actually has the capability to have 8.8 volts. If you charge it with 7 volts, you'll have a relatively flat battery most of the time....you could do this and charge it once in a while, but it won't be good for the battery cells to be partially charged most of the time. So...you could dial up the regulator to 9.5 volts (or close) to keep the battery in good shape, but you'll be hitting the 6 volts accessories with 50% more voltage than they were really designed to work with. Dialing up an adjustable regulator is really as simple as adjusting the spring tension on the regulator points inside the regulator...get the manual...there are 3 elements inside the regulator...a voltage regulator circuit, a current limiter (the one with fat wires in the winding), and a reverse current cutout...it essentially turns off the regulator when you turn the key to the off position.


Dan