I know this has probably been asked before but here goes.

1985 K100RT.

Saw charge lamp glowing at high rpm.
And again at low speed when I hit the brakes.

Battery is about 3+ years old.

Could that be the problem?

Gerry

If it is a K100 RT which it probably is then there is a fix.

RicK G wrote:If it is a K100 RT which it probably is then there is a fix.

Yep, it is.

Sorry for the typo

You splice in a diode to the blue wire that goes to the alternator with the arrow pointing to the alternator. you would need a diode that is capable of 5 amps. Put heatshrink tube over the wire when you cut it so it can be slid down over the diode and exposed wire after soldering.
This mod is not necessary for the correct functioning of the bike but will prevent the soft glow of the light.

I installed a new 30Ah Motobat... no more soft glow from the charge light. Previously the battery was on the way out and I got stuck once with a 'no start' while out. The new Motobat was on the garage floor at home

It works the other way round too. If the battery is no good, the current will flow from the alternator and the bulb will glow.
Your battery may still be working but it could be getting boarderline which is likely at 3+ years.

Kaptain Holister wrote:I installed a new 30Ah Motobat... no more soft glow from the charge light. Previously the battery was on the way out and I got stuck once with a 'no start' while out. The new Motobat was on the garage floor at home

It works the other way round too. If the battery is no good, the current will flow from the alternator and the bulb will glow.
Your battery may still be working but it could be getting boarderline which is likely at 3+ years.

OK, thanks, I guess battery is going to get changed.

We will see after that.

Safe riding.