Wiring loom power loss!

[manicguitarist]

Oh my!

Let me re-iterate, my bike is running fine. Holds charge. Charges the battery. Starts on the button.

Anyways, bored tonight. Looking at doing the wiring mod as recommended by some on here to keep the reg/rec cool. Figured I might install a digital display of the voltage once I've done the mod - so I can keep a track on the voltage. And, ok. It is a shiny light. I'm a sucker for things that glow and are shiny. :)

Like I said I was bored.

So - looking around the wiring loom - across the battery - bike off - 12.4V, bike on (i.e. lights on, but no engine) - 12.1V

I'm ok with that.

However measuring the potential difference at various places around the wiring loom shows how much power is lost in the loom - which lends a lot of credence to the wiring mod (where you take the output from the reg/rec directly to the battery).

At the rear brake switch 12.0V
At the rear bulbs - but not connected to the bulb - 11.75V
At the headlights - but not connected to the headlights - 11V
At the headlights - and connected to the headlights - 10.25V

Wow - the wiring loom seems to have a fair bit of resistance to it.

Anyways...just sounding off really. I'll shut up now and get some beer. :)

[magg]

Not sure what the difference in measurement technique is for "At the headlights - but not connected to the headlights - 11V" and "At the headlights - and connected to the headlights - 10.25V" but the differing voltages throughout the loom is beacause there is only two wires distributing the majority of electrical power to and from each electrical load, not necessarily poor wiring condition.

If you want full battery voltage at each electrical unit ie headlights, tail-lights etc, then you need to run individual wires from the battery to each unit.

Obviously such an arrangement would not be cost effective or practical for the OEM.

Having said that, heavy gauge wiring to the headlights is a worthwhile mod for those that do a lot of night time running. Can make a noticable difference when bulbs run at 14 volts and not 10-12 volts.

[manicguitarist]

At the "headlights but not connected" was - I pulled the connector block off the light and measured there. For the "connected to the lights" I opened up the back of the block and measured with the lights being powered by it.

M

[magg]

Right, voltage at headlight terminal falls when headlight is on. Reasonable result given the OEM loom configuration. Wiring mod as suggested above would improve this situation.

[Neosophist]

Having said that, heavy gauge wiring to the headlights is a worthwhile mod for those that do a lot of night time running. Can make a noticable difference when bulbs run at 14 volts and not 10-12 volts.

amen to that.

headlight wiring is interesting, it does cause a lot of debate too.

You can use the minimum spec wire-gauge (as a lot of oems do, it uses less copper and saves money, also can prolong bulb life)

headlight stuff

this is a very good read about bulbs and how voltage drop on long runs of thin wire reduce the brightness of the bulbs a hell of a lot.

My one NC30 I converted to H4 with adapter rings and installed 2 new relays with a direct feed from the battery for power using 2.5mm sq cable and a nice earth on the bulbs too.

I think i still have pictures somewhere.

Stock 55/60 bulbs were super bright on the 30 :)

[Morespeedvicar]

I made a separate headlight loom with relays too.