Anyone Understand Kalkoff ProConnect Lighting

oriteroom

Esteemed Pedelecer
Jul 13, 2008
297
110
Hi all

Sure someone will be able to answer my query re the lighting used on the Kalkoff Pro Connect. I've the diamond frame and Mrs 'O' has the step thru' both just over 2 years old. I've read before on this forum about some contact/water ingress problems on the rear lights - bared wire ends are just clamped in place. Mrs 'O' rear light began to become intermittent a while back, and for a while would respond to the old 'give it a a tap' or 'wiggle the wires'. Stopped working altogether, so I thought it time to sort it out especially with the clocks going back in a couple of weeks :( . Cleaned wires etc and found as well that the bulb filament was now broken. We have other lights fitted as well, but it's always worth using all you've got!

NOW to the query....

Whilst checking supply/continuity, I noted that the voltage was about 1.2V on the rear light (which has a 6V 0.6W bulb fitted) but that the voltage on the front bulb was just over 6V. I couldn't understand why the rear light voltage would be that low so opened up the rear light on my Pro Connect and checked that as well - it too was about 1.2V! Bought a new 6V bulb and everything is fine - EXCEPT I don't understand why? Why does the rear 6V bulb shine bright on 1.2V supply. Is my meter wrong? Why does it read 6V+ on the front light? I know there must be some sort of 'circuitry' to get the 24V battery to power the lights - is that where the answer lies?

Any thoughts?
 

flecc

Member
Oct 25, 2006
52,803
30,376
You can't measure the voltage that way Mike, due to the way the voltage is derived.

The lights are fed from the Panasonic unit, and it's lighting circuit chops the 26 volt supply in a rapid series of on/off pulses. These are arranged so that the on pulses are much shorter than the off pulses, leaving the average voltage out as about 6 volts continuous. Since that on/off pulse stream is more like an irregular AC voltage, trying to measure it as DC produces unpredictable results, depending on the loadings at the point where you measure it. Using the AC scale might work better, but the asymmetry of the pulses may still produce odd readouts.

Best viewed on an oscilloscope to see the pulses.
.
 

oriteroom

Esteemed Pedelecer
Jul 13, 2008
297
110
Thanks flecc - knew there'd be an answer :) .