Dim headlights at an idle identified...the fix?

[Bluefront]

This would be easier if I had the correct wiring diagram for this Eagle Sporty...but I don't. But no matter.

This scooter has dim headlights when the engine is idling, and at an idle they also pulse. Apparently other scooters have this problem. The headlights come on only when the engine is running......that's the clue. The problem.....the headlights are never powered through the battery. Instead they are powered by the un-rectified output of the stator (I think that's the correct term). The proof....the headlights are running off an AC voltage, not a DC voltage from the battery. Check out this photo...



In the photo, the scooter is idling with the low beams on. The volt meter on the right shows battery voltage. The VOM on the left is showing the voltage to the low beams......note the selector on the VOM is on AC voltage. It will not register if it's set to DC. If you rev up the engine, the AC voltage goes up to about 12V, and the headlights are bright.

Here's my proposed fix.....run the headlights off the battery circuit. I'll find the input wire to the hi/lo beam switch, and using an automotive relay, power it when the ignition is on, by DC battery voltage. That will solve the dim/pulsing problem.

The down-side.....the lights will turn on when the ignition is on (I could add an on/off switch I suppose). And I'm not sure if the charging system can handle the slightly extra load. I'll have to think about this for a while....I'd appreciate any ideas on this matter. I wasn't able to find anything using the "search". That dim headlight thing bothers me. The tail light is running on DC from the battery.....it never dims. I'd like the headlights to perform the same.

[indy50]

You are correct, the headlites are AC voltage, but the voltage is rectified
Most often dimming at idle is due to a ground issue

Chinglish diagram :
store.oohla.com/storefiles/terminatorscooter//download/accessory/2615/dlt.pdf

[Bluefront]

Well no matter how good the grounds are, unless the voltage to the headlights is higher than 7.7 at an idle, the lights will be dim. It's not a ground problem, IMO.

I tried running the headlights directly off the battery. They are nice and bright, with no flickering, with the engine idling.

But......the charging circuit is simply too weak to wire the lights this way. When running, the battery voltage won't get much over 12V, no matter how high you rev it. It should be around 13.5-14.5V @ 3k RPMS (aprox). Eventually the battery would go dead.

So....any other solution for dim headlights at an idle? Raise the idle speed is the only other thing I can think of. At 2200 the lights are much better at an idle. Still thinking on this one......

[indy50]

If you put your meter on your battery terminals, you should read 12 - 12.5 vac, when revved at 4000r, your reading should be somewhere in the 14's

Sounds like a weak stator

[cruiser66]

Sounds like your scoot lighting circuit is acting normally. Around 12 AC volts to the headlights when driving is about all it will put out. The DC charging system on these scoots isn't designed to run lights. You might want to consider converting your system to full DC if the dim lights at idle really bother you.

scootdawg.proboards.com/index.cgi?board=talk&action=display&thread=8929&page=1

66

[Bluefront]

^^^^Thanks for that link. Obviously I'm not the first person to wrestle with this problem. But since I'm only wanting to run the stock headlights off the battery (no HIDs), I'm not willing to go through all that trouble/expense.

Other possible solutions.....

Install an on/off switch for the headlights, and only turn them on at nighttime on DC.

Rewire the headlights so only one is on during the day (My scoot has two 18W headlights). Keep the battery on a small trickle charger when I'm not using the scooter.



Wire it so the high beams work off AC, and one low beam off DC.

I don't usually ride the scooter after dark, but I like the safety aspect of headlights on during the day.

Forget the whole thing and just crank up the idle speed....that woks, not perfectly, but ok.

I wonder does anyone sell an easy bolt-on DC conversion kit?

[tstubbs]

what about a stator upgrade? This may work to help the RPM vs Voltage across the board.

www.ecrater.com/product.php?pid=5388030

[Bluefront]

^^^^^That might work if the battery charging circuit was powerful enough to do the job. But you'd probably have to buy the thing and try it yourself to know for certain.

[cruiser66]

Nov 16, 2009 11:14:38 GMT -5 tstubbs said:

what about a stator upgrade? This may work to help the RPM vs Voltage across the board.

www.ecrater.com/product.php?pid=5388030

You would have to also change the flywheel/magneto to match the stator. Then you would also have to the get the matching regulator/rectifier.

66

[Bluefront]

Yep....that's the thing. There doesn't seem to be a complete kit available that gives you a more powerful charging circuit. The "performance" stator kits are designed for racing apparently (lighter flywheel). They mention nothing about increased charging capacity.