Lights Draining Battery

[fjzr04]

Well, it is well known that a battery will be drained if the engine is not running or the charging system is not working properly. So this leads to my question, is it possible that a fully functional charging system will not maintain charge while running the headlights?

I did a 150 mile run the other day, I ran the headlight for safety measure, about 2 miles from my house stop at a light and the bike just dies, this after running flawlessly for 150 miles. So I walk the bike over to the emergency lane and try to start it with the starter and no dice, so then I kick start it and it starts right up.

I put the bike on the battery tender and it has run without a hitch, mind you, less headlamp. So, as I am not an electrical expert, regulator is new and not sure what is going on, or maybe, the bikes system is not made to run the headlights continuously.

Bike is a 1977 XS 650 running a Pamco ignition, just about the only upgrade done to the engine

Thanks

 

[I am Carbon]

the stock charging system will keeps the battery charged while running lights.
Get a voltmeter so you can test voltage
Get the battery terminals exposed so you can test for voltage
while the engine is running at around 2000 to 2500rpm use the voltmeter to see what the voltage.
I take it you have a light switch
I would do the test lights on and lights off if you have a light switch, note the voltage during the tests voltage should be 14.5 volts plus/minus .5 volts
If volts are too low then charging system trouble shooting will be in order
if volts are okay then get battery tested.

 

[retiredgentleman]

If the charging system is working properly, then running the headlight full time is not a problem at all.

Your battery may be old and starting to fail. Battery sellers have "load testers", but your starter motor is also a load tester. The starter motor draws a very large current and pulls down the voltage low enough that the ignition becomes very weak, if the battery is not fully charged.

You need to do some testing. Fully charge the battery with a bench charger. Start the engine, wait a few minutes, turn on the headlight, rev the engine to 3500 to 4000 rpm and measure the battery voltage at that rpm. The voltage needs to come up to 14 volts. If it only rises to 13 or 13.5 volts, then that explains why your battery is weak after 150 miles.

 

[fjzr04]

Thanks I will check voltage and report back, now to get a voltmeter. Any recommendations?

 

[xs650custombuildzz]

Centech 61593 $40 from amazon, great meter