Bit of a project.

[gavbriggs]

I've been thinking about this all week.

On modern ish bikes the headlights come on with the key. That's all well and good but then you need extra power to start the thing.

Could a relay be fitted so the head lights only came on when the engine was running?

I want this specifically for my 1200s k4 bandit. Is there a signal wire on the alternator and where could I put this relay?

Cheers

[Islander]

If you have an electronic tach, you could tap into the pulse feed , buffer it off and integrate (smooth) it to provide a control voltage.

Or just turn the lights off.

[gavbriggs]

[lihp]

It is hard when you have no clue what you're doing.

If you can't start the bike with headlight on, then you have a battery/charging/starting issue
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[Islander]

[Islander]

[mikesaa309]

I'm no expert but could you not just wire it into a wire that has power when the engine starts up? I doubt you could wire it directly to the alternator unless maybe connecting it to the wires leading out of the engine casing.

My bikes the opposite, my lights come on once the engine is started. I've thought about rewiring it to come on with the ignition. However I can't think of anything else that would only produce power once the engine is started.

So from the top of my head, I don't think it can be done. I think I'm right in saying that my head lights are directly wired into the alternator which won't be easy to do.

That said I wouldn't think that it would loose much power if any if the lights are on. It's designed to work that way so doubt it'll be much of an issue.

[gavbriggs]

The bike starts fine, well it does now I've sorted the carbs/dodgy fuel/electrical connector issues I've had.

But while I was sorting those issues I had to use my jump battery (120ah heavy duty 4x4 type) that I keep topped up just in case I should need it to assist the bike. Obviously the bike battery isn't powerful enough for multiple starts.

That's what got me thinking that if an issue did arise it would be helpful not to have the headlamp drawing power, which could be the difference between riding home or pushing home.

I did however unplug the headlight bulb so I would just do that I suppose if the need arose!

[mikesaa309]

[WD Forte]

there are various ways of doing it.
Dont know the bandit but many bikes have a disable function to
cut power to the lights when cranking.
Others will only turn on running lights at first and use a tap into one of the alternator output cables to power a relay which will turn on the lights after the engine has started.
This tap has to be rectified of course.
the lights will turn off when the engine stops.
A manual switch is another and probably the simplest option
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[gavbriggs]

The bandit has the two rear lights = 2x5w, the front sidelight = 5w plus the front headlight = 50w

Just wondered if nocking the 50w out would save a bit of wear on the battery.

It'd definitely be a relay to the main beam. As I would forget a switch and I think the auto front lights on system is a massive safety improvement over the optional lights of old!

[misscrabstick]

My MT09 has no lights on/off switch, however when i turn the ignition on only the sidelamps come on and the headlamp comes on when the engine is started. Some sort of battery voltage sensitive relay control i guess.