TS 125 Charging light

[Ollie Harris]

Hi
Whilst filling my bike with petrol this morning, I noticed the the charging light was no longer illuminated, regardless of the ignition switch position.
I carried on into work, with no problems. There was no sign of the battery being flat.
I fitted an electronic flasher relay a few months ago, meaning separate circuits for the charging light and the indicators. So i’m fairly sure I can rule out indicators.
All the bulbs etc worked at full brightness. if it wasn’t charging, the battery would’ve been flat by the time I reached work (headlight on dip, plus sidelight, rear light instrument lights, on a 5Ah battery, over a period of 45 mins – it would at least have shown some signs of a discharged battery.)
I’ve checked the dynamo for any loose wires, all are secure and the brushes have plenty of life in them. Other than a blown bulb, I’m out of ideas.
Does the lack of charging light mean the battery is not charging, or is it more likely to be a fault with something else?
Any help would be appreciated, I dont want to ride home holding a torch!

• This topic was modified 10 years ago by Ollie Harris. Reason: Can't spell

[Anonymous]

Hi Ollie,

Presumably the charging light worked correctly after you fitted the electronic flasher relay. If so then you can probably discount that as a possible cause.
The first thing is to check the bulb but you could also check the charging by connecting a multi meter across the battery. With a charged battery you should get a reading of 6 – 6.5 volts. Turn on the ignition switch and the voltage will drop a small amount when the points are closed. Now start the engine and the meter should read upwards of 7+ volts indicating that the dynamo is charging. No increase in voltage will indicate a fault in the dynamo, regulator or wiring.
You don’t need a fancy meter, a small digital one will be very cheap and very useful for fault finding once you have got used to it.
Good luck.

[Ollie Harris]

Thanks for the reply. All was OK, and rode the bike home after checking the voltage across the battery. voltage was around 7v. Assumed it’s the rubbish bulb holder, and have left it alone – something to investigate on a rainy day.
Maplin was just across the road, so bought the cheapest one they had. Now it lives in my toolbox.
If I had been at home, I would’ve used my normal, analogue voltmeter – it’s easier to visualise what’s wrong when there’s a dial involved!

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