Mckorkins wrote: ↑Sun Oct 29, 2023 10:16 am
Thanks fellas. I take on board what you suggest. But why on earth does the ammeter swing to positive? It doesn't happen with the lights, which act normally and registers a discharge. The wiring loom is fairly new and so I don't think there's a problem with that. Anyway, I'll check things out as you suggested. Honk!
Because the lights are wired through the ammeter.
Anything not wired through the ammeter will create an 'unseen' drain on the battery when activated. The regulator is in constant 'discussion' with the battery and 'has its back' as it were, so it detects the drain and asks the dynamo (or alternator) to make up for it.
The regulator also asks the dynamo or alternator to compensate for the loads imposed by the lights as you say, but they are already recognised as a drain by the ammeter, so what you see is the needle swing positive as the engine revs and then towards negative as revs drop to tickover or the engine is stopped.
Very fundamental - and helpful. Got that; but why does ammeter swing "+" when the engine is not running?
As Groily mentioned, with the standard (factory) loom the power for the horn doesn't pass through the ammeter so operation of the horn should have no effect on the ammeter needle.
Has the ammeter needle always moved to Pos when the horn was operated, or has it ocurred since you've done something to the electrics - like removing the battery to charge it and replaced it with the battery connections inadvertently reversed?
A picture being worth a thousand words...........
Wiring. Horn. 56 single b.jpg
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'There is a tide in the affairs of men
Which taken at the flood............'
SPRIDDLER wrote: ↑Sun Oct 29, 2023 2:46 pm
As Groily mentioned, with the standard (factory) loom the power for the horn doesn't pass through the ammeter so operation of the horn should have no effect on the ammeter needle.
Has the ammeter needle always moved to Pos when the horn was operated, or has it ocurred since you've done something to the electrics - like removing the battery to charge it and replaced it with the battery connections inadvertently reversed?
A picture being worth a thousand words...........
Wiring. Horn. 56 single b.jpg
Thanks for the diagram. I've rewired the bike sometime ago now, but done nothing untoward like removing the battery and reversing the polarity. In fact, I fitted a new battery yesterday and double-checked that the polarity was correct (+ earth). This afternoon I removed the seat and adjusted the horn slightly, which now 'beeps' okay, but the ammeter still swings to +. The dynamo is working correctly and showing a positive charge when the engine is revved. If it's an unknown/unsolvable problem, I'll have to live with it!
SPRIDDLER wrote: ↑Sun Oct 29, 2023 2:46 pm
As Groily mentioned, with the standard (factory) loom the power for the horn doesn't pass through the ammeter so operation of the horn should have no effect on the ammeter needle.
Has the ammeter needle always moved to Pos when the horn was operated, or has it ocurred since you've done something to the electrics - like removing the battery to charge it and replaced it with the battery connections inadvertently reversed?
A picture being worth a thousand words...........
Wiring. Horn. 56 single b.jpg
Thanks for the diagram. I've rewired the bike sometime ago now, but done nothing untoward like removing the battery and reversing the polarity. In fact, I fitted a new battery yesterday and double-checked that the polarity was correct (+ earth). This afternoon I removed the seat and adjusted the horn slightly, which now 'beeps' okay, but the ammeter still swings to +. The dynamo is working correctly and showing a positive charge when the engine is revved. If it's an unknown/unsolvable problem, I'll have to live with it!
Actually, looking at your diagram again, I wonder whether the horn wire is connected to the wrong terminal on the ammeter. That would cause the problem, no?
The feed should come off the side of the ammeter that is also connected to battery live. (Not the side that goes, in Spriddler's diagram, to switch position 3.)
If it's coming off the other side, the load will register, yes.
The fact that the ammeter presently shows a charge, not a discharge, suggest that the wires at the horn itself should be swapped. Horns aren't polarity sensitive as Reynard 24 said, but an ammeter will show + or - depending on which way current flows round the circuit.
I'm sorry to have misunderstood your Q about the needle showing + earlier on!
