01-02-2020, 12:37 AM
(This post was last modified: 01-02-2020, 07:37 AM by Bob Culver.)
The original bulbs were only 18w and the charging system can safely match only this. Most now have much larger bulbs and especially with these if the battery is lowish the sytem voltage can dwindle below 6v. With the 3 brush system as volts dwindle so does the charge so get into a downward spiral. If stuck far from home disconnect one lamp). Vintage car owners often report worse lights with larger bulbs.
For any who may be unclear, when measuring volts at some point of interest doing so under working conditons at that point is important. If there is no local current being drawn you are effectively measuring the voltage at some distant point. The 5v with other light on would be volts at switch output or any later last point of shared current (and somewhat low for whatever reason, esp for one lamp)
I ran my car with 6v 21w BPF motorcylce bulbs (vertical dip to upset the wof inspectors) but may not now be available
For any who may be unclear, when measuring volts at some point of interest doing so under working conditons at that point is important. If there is no local current being drawn you are effectively measuring the voltage at some distant point. The 5v with other light on would be volts at switch output or any later last point of shared current (and somewhat low for whatever reason, esp for one lamp)
I ran my car with 6v 21w BPF motorcylce bulbs (vertical dip to upset the wof inspectors) but may not now be available