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Posted: Wed Apr 15, 2015 10:43 am
I have noticed lately that my lights dim when rolling off the gas when stopping for a traffic light or stop sign. Of course it is not noticeable during the day but is quite noticeable at night.
I have no real added load except for my add on XM radio so I am not putting a strain on the system.
Is this a sign that I am due for new brushes in the alt? Or, should I bite the bullet and get a new COMPUFIRE alt with its higher output?


Posted: Wed Apr 15, 2015 11:00 am
by virgilmobile
Have your battery load tested then clean and tighten the connections at the posts before you jump to the alternator.


Posted: Thu Apr 16, 2015 2:43 pm
by PastoT
If your high beams or fog lights are on they add a significant additional pull on the battery/alternator, even more-so if your bike is modified to keep the fog lights on when you flip your high beams on. My voltage is typically 14.1 or 14.2 volts at speed but with my fog lights and high beams on (all 6 headlights) I read 13.9 at speed; idling down at a stop sign or intersection I loose about .3 more volts and the lights dim a bit. I recently changes out the 13 y/o OEM battery and notice it less but it still happens. Certainly a waning battery or poor connections are always worth checking and a fast fix if ailing, but it may be simply the lowered RPM of the engine and alternator producing only a bit less voltage making a dimming noticeable.