Ariens 42" riding mower headlight wiring- bad design

[Gym123]

New guy here, first time with a mower that has a drink holder.

I got a 42" riding mower a couple of days ago that needs things (head gasket, who knows what else after that?) and so far, I haven't seen the headlight operating, so I looked at a schematic and it shows that it "has a special alternator system. The headlights are not connected to the battery, but have their own electrical source." (in the link below, next to the diagram of the ignition switch).

Why would they allow the headlight brightness to vary with RPM? That makes no sense. Well, other than lower cost by not using a better voltage regulator. I haven't found a service manual with specs yet, so I'm working a bit blind on this. Gas had water and debris, so I drained/cleaned the tank, changed the oil, will change the fuel filter and spark plug today and order the correct head gasket ASAP.

My questions-

Will the alternator have a problem if I use the headlight + wire to activate a Bosch-style relay, then supply battery voltage to the lights through the relay so it's more stable? That way, the lights will only work when the engine runs, but RPM won't cause them to dim (as much).

I plan to check the bulbs for draw before doing anything like this but will use LED if the alternator is at the edge of its capacity.

I worked in car audio/security and as a marine mechanic, so seeing this kind of wiring makes my eye twitch.

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Thanks, in advance.

 

[ILENGINE]

If that engine and mower setup has what I think it does, you may not have enough amps to charge the battery and also power the headlights. That setup uses the 3 amp side of the stator which is half wave rectified via a diode to charge the battery and the 5 amp AC side to power the headlights. The headlight bulbs will be at most 25 watts each so 50 watts total for a system that generate roughly 60 watts for headlight power.

You could always replace the stator under the flywheel to the 9 amp system and install a voltage regulator and then power the system like your discussing. And what you are complaining about the headlights has been used for more years than I have worked on them, and that is a long time. And personally headlights on a mower are a total waste anyway since they are about bright enough to drive from the yard to park in the garage. They are not bright enough to mow with them.

 

[Gym123]

If that engine and mower setup has what I think it does, you may not have enough amps to charge the battery and also power the headlights. That setup uses the 3 amp side of the stator which is half wave rectified via a diode to charge the battery and the 5 amp AC side to power the headlights. The headlight bulbs will be at most 25 watts each so 50 watts total for a system that generate roughly 60 watts for headlight power.

You could always replace the stator under the flywheel to the 9 amp system and install a voltage regulator and then power the system like your discussing. And what you are complaining about the headlights has been used for more years than I have worked on them, and that is a long time. And personally headlights on a mower are a total waste anyway since they are about bright enough to drive from the yard to park in the garage. They are not bright enough to mow with them.

This makes me want to ask "What was the point?".

You service this kind of machinery as a job? I'm still getting info (manuals, etc)- is there a source of service manuals for these with specs?

Also, when I removed the fuel filler cap, I saw parts in the tank but I don't know what they're used for-

 

[StarTech]

The bulbs are common 1156 bulbs that @12.8 V draws 2.1 amp each.

The dual stator was used to keep costs at a minimum. Besides most don't mow grass in the dark. Lights are mainly for safety but most people can't see pass the phones; unless, your equipment is as big as a 18 wheeler. And even mower with lights powered a good system are this pretty well worthless.

If this is a used mower those parts are probably from a fuel container nozzle.