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Hey all,

I added the HD fork mounted driving/passing lights to my Dyna ('01 FXDL) and have really enjoyed the additional light during night rides. I usually get voted to ride lead since my bike now illuminates the road so well (plus the guys get tired of 3 lights reflecting in their mirrors).

See picture from HD website (P/N: 69284-05)

Overall I'm very happy with the look and performance EXCEPT....

The lights dim brighten with RPM. When I downshift, and RPM jump a bit, the lights become momentarily brighter. When cruising at stable RPM the lights are stable. When at idle (RPM around 1100ish) (stop sign / traffic light etc) the lights are notably more dim that while cruising (1900 to 3000 rpm).

I'm wondering if the lights are putting a greater strain on the battery / electrical system than what it is intended to handle.

Any suggestions or expertise would be appreciated.
 

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From the info I have, your 2001 FXDL came stock with a 32 amp permanent magnet alternator. Assuming that is what is still on your bike, and that it and the regulator are functioning properly, the charging system should be able to handle the extra load of the additional lights you installed. Thats assuming that there are no other non-stock electrical items installed on your bike. Without a doubt, the addition of the passing lamps will require the charging system to work more.

How old is the battery? It should show approx 12.5 volts DC with the bike off. Make sure that all connections to and from the battery are secure and that no corrosion is present. If you have a battery tender, or similiar, hook it up and assure that it is able to give the battery full charge.
Even if all those things are confirmed, an older or inferior battery can place an additional burden on the charging system. Performing a load test on the battery is the best indicator of the health of a battery.

Assuming the battery checks out, check that it is receiving proper charge while the bike is running. You should see approx 14.5 volts DC accross the battery terminals with the bike running. Voltage will be lowest at idle and will increase with RPM's. Should not go much higher than 14.5 volts.
In addition, check wiring from the stator to the voltage regulator and the ground for the voltage regulator.
There are some good tests for these two devices in the 2001 HD Electrical Diagnostic Manual # 99495-01
 
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