How to determine if your alternator is under powered

[captain_ramshackle]

I have the following scenario.

Honda CG125 (2008) which starts perfectly fine with the electric start normally. Then riding for a period last night (1 hour) on main beam (country lanes) it wouldn't start after stopping.

A bump start got it going and a 30 min ride on dipped lights got it to the point where it would start fine.

This makes me feel that the charging system isn't powerful enough to run the bike and main beam, but I can't work out an easy way to check it.

At the moment I lack the following

Multimeter & battery charger

I'm going to have to get the multimeter as otherwise I may as well just wave a chicken at the bike and use voodoo.

[G]

What sort of bulb(s) does your bike use?

On a CG I would expect it would use a single bulb which does either dipped or main beam; only doing both at the same time if a 'pass' switch is activated.

That being the case, there shouldn't be significantly higher drain on main beam, so might point to another issue.

[1198]

[captain_ramshackle]

[monkeybiker]

My money says you need a new battery.

[G]

[captain_ramshackle]

[G]

Actually, first off, I'd be checking the way your bulb works, as already suggested.

If both come on at once, I'd check if they are supposed to - it may have been bodged by a previous owner to do so.

You can test the voltage drop across the battery with each one on.
Also worth testing the amps drawn.
Presuming it is higher, then it's a case of working your up the wires until you find the problem.