Fuse for generator

[47chief]

Putting a cycle electric generator on the chief. Fuse the positive or negative? thanks

[pisten-bully]

Putting a cycle electric generator on the chief. Fuse the positive or negative? thanks

Personally, I don't run a Cycle Electric, (mine's a 12V Frank Vandevelde job) but I wondered the same thing and found divergent opinions on the matter! So for me, I've got a 20 amp self re-setting circuit breaker on the positive wire just above the battery. +15k miles and no issues.

[Sargehere]

As a rule, "always fuse the hot wire," (+) given a choice. That way in case of ground or overheat, the fuse burns out first, not the item overheating.

[BoschZEV]

I wondered the same thing and found divergent opinions on the matter!

I googled this to see what is written and, as always seems to be the case with "information" on the web about automotive electrics, most of what is there is nonsense.

As a rule, "always fuse the hot wire," (+) given a choice. That way in case of ground or overheat, the fuse burns out first, not the item overheating.

Put the fuse in whatever lead allows you to have it as close to the battery as possible. It doesn't need to be 'close' for functioning, but to minimize the length of unprotected wire.

As far as the electrons are concerned, whose opinion on this is the only thing that matters, both wires are equally "hot." The same current always flows into a battery as out of it so if there is a malfunction anywhere on the bike that causes too much current to flow the fuse would blow whether it's in the '+' or '-' lead.

As a relevant aside, we universally call the battery lead connected to the frame "ground" (or "earth"), but this is a misnomer. Household and industrial wiring do have 'ground' wires that run to the actual Earth, i.e. the dirt outside the building, so that if there is a malfunction of, say, a washing machine the outer housing can't get to 110 Volts. However, absent a short in the rest of the wiring those 'ground' wires carry no current and the circuits would work just as well without them. Emphasizing this, "ground fault interrupters" (GFI) are in wall sockets in places like bathrooms of relatively new houses. These trigger circuit breakers if they detect even a tiny flow in the 'ground' wire.

Anyway, in a DC circuit like on a motorcycle there is no ground/earth despite our common (mis)use of the term. Both the '+' and '-' sides of the battery are equally important so a fuse can go in either wire. Remember, British motorcycles commonly used a positive earth/ground which functions just as well as the negative ground that is common on American machines.

[tfburke3]

If the fuse is on neg battery post and blows while running,does the generator stop putting current into a overloaded or shorted circuit ?
If its on the pos does the generator continue to generate ?Any difference in this scenario?
Interesting that the factory used no fuse.
Thanks
Tom

[BoschZEV]

...does the generator stop putting current into a overloaded or shorted circuit ?
If its on the pos does the generator continue to generate ?Any difference in this scenario?

Please post a wiring diagram and we can discuss it.

[pisten-bully]

Please post a wiring diagram and we can discuss it.

Whoops! Looks like the folks in Springfield called negative "ground"

[BoschZEV]

Whoops! Looks like the folks in Springfield called negative "ground"

Lucas did the equivalent in their wiring diagrams, calling the positive "earth" (but, later British bikes came with a different polarity, so in those they called the negative "earth").

The first thing I can say is everyone who owns an Indian should complain to the factory for supplying such a lousy wiring diagram. No wonder there is confusion. Nowhere are the "ground" connections shown other than the one from the '-' terminal of the battery. I've drawn the two relevant ground connections in red on the attached diagram:
Indian_wiring.jpg
The "ground" wire from the '-' terminal of the battery goes to the frame, and the housing of the generator is attached to the frame providing that essential connection as well. Electrons are given 6V potential by the generator and flow through the black wire output from it through various switches and ammeters to finally reach the '+' terminal of the battery. This process would come to an instantaneous halt unless those electrons emerged from the '-' terminal of the battery, through the frame, and back into the generator through its housing (which I represented in this attachment as if it were a wire). This means if a fuse were in either the wire attached to the '+' terminal of the battery or the '-' terminal, either way the generator would cease to do anything useful if the fuse blew.

[tfburke3]

Lucas did the equivalent in their wiring diagrams, calling the positive "earth" (but, later British bikes came with a different polarity, so in those they called the negative "earth").

The first thing I can say is everyone who owns an Indian should complain to the factory for supplying such a lousy wiring diagram. No wonder there is confusion. Nowhere are the "ground" connections shown other than the one from the '-' terminal of the battery. I've drawn the two relevant ground connections in red on the attached diagram:
[ATTACH=CONFIG]17423[/ATTACH]
The "ground" wire from the '-' terminal of the battery goes to the frame, and the housing of the generator is attached to the frame providing that essential connection as well. Electrons are given 6V potential by the generator and flow through the black wire output from it through various switches and ammeters to finally reach the '+' terminal of the battery. This process would come to an instantaneous halt unless those electrons emerged from the '-' terminal of the battery, through the frame, and back into the generator through its housing (which I represented in this attachment as if it were a wire). This means if a fuse were in either the wire attached to the '+' terminal of the battery or the '-' terminal, either way the generator would cease to do anything useful if the fuse blew.

Thanks for that detailed explanationBoshZEv,
Tom

[47chief]

thanks for all the info. i think i'll go with positive

[larrymgibson]

As a long time journeyman electrician and Indian owner, I suggest we call + (positive) the "hot" wire and - (negative) the "common" wire. Probably no more accurate, but it doesn't use "ground" or "earth'.

Larry Gibson

[OldMCRider]

I had the negative wire come loose and fall of of its connection. The generator voltage went up almost immediately and burned out the headlight and the brake light.

[RonH]

I used a wire from the generator body to the negative terminal on the battery just for a good "ground".