Wiring a brake light.

[jimriley]

Hi. I am awaiting delivery of a rear light/brake light from China. I've fitted a front light with beam pattern, also a horn, I took a fused spur off the battery out wires. So the tail light will be joined to the headlight. I also fitted a USB feed for the phone and to charge the see.sence lights.
How do the brake switches work? How do I get a switched feed to the tail light?
Thoughts welcome, thanks.
I got a free pair of see.sense ACE with British Cycling membership, they are great but I'd like lights off the main battery too.

 

[vfr400]

If you have cable brakes, it's dead easy:
1. Tape a read switch to the frame and a magnet to the cable.
2. Use a micro switch with a lever attached to the cable
3. Use a motorcycle type switch and clamp the spring to the cable

You can use all those methods on hydraulic brakes, but you have to use a moving part of the lever to actuate it. Alternatively get a Magura inline hydraulic switch

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[jimriley]

Thanks, I'll have a look at, those ideas. The rear see.sense ace has a brake self sensing function. Just looking at making use of the possibilities.

 

[trevor brooker]

If you have cable brakes, it's dead easy:
1. Tape a read switch to the frame and a magnet to the cable.
2. Use a micro switch with a lever attached to the cable
3. Use a motorcycle type switch and clamp the spring to the cable

You can use all those methods on hydraulic brakes, but you have to use a moving part of the lever to actuate it. Alternatively get a Magura inline hydraulic switch

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I too am thinking about having a brake light activated by pulling the brake lever.
I am also running the lights off the main 48v battery.
Looking at 1-3 will any of them accept sufficient volts/amp to power a rear light, as I want to keep the wiring simple. Power to switch to light. Although I can only think how to use one brake pedal to activate the brake light.

 

[vfr400]

I too am thinking about having a brake light activated by pulling the brake lever.
I am also running the lights off the main 48v battery.
Looking at 1-3 will any of them accept sufficient volts/amp to power a rear light, as I want to keep the wiring simple. Power to switch to light. Although I can only think how to use one brake pedal to activate the brake light.

volts is no problem. it's current that kills switches. The switch has to be rated for whatever current your light draws, which isn't much for a back light. the 14mm reed switches are rated at 0.5A max, which is 24w at 48v.

See the microswitch on this that clamps onto any open cable. I used to buy these 10 years ago just for the switch before you could buy HWBS inline switches.

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[trevor brooker]

volts is no problem. it's current that kills switches. The switch has to be rated for whatever current your light draws, which isn't much for a back light. the 14mm reed switches are rated at 0.5A max, which is 24w at 48v./QUOTE]

Do you mind if I ask an obvious question but I am ignorant of the correct answer.

I have hydraulic brakes so the microswitch on this that clamps onto any open cable will not work.

So I propose to use the Reed switch mounted on the brake lever adjacent to a magnet.

My question is I presume I need a Normally Closed switch which turns on the power when the Reed is moved away from the magnet, but I was unsure if I had correctly reasoned the way it works, lack of sleep from providing 24 hour care is muddling my thinking.

 

[jimriley]

Wuxing rear / brake light arrived yesterday, ordered 2 long lever microswitches, should be here today. I have racks front and back so hoping to use them to mount the microswitches above the v brake arms.

 

[vfr400]

Trevor, it depends on whether your arangement causes the magnet to move towards or away from the switch. You can get reed switches that have two leads on one side for NO and NC, which gives you a choice.

 

[jimriley]

Job done, used 2 long lever microswitches, one mounted on an aluminium bracket, the other on the front carrier.
Wiring all contained in a small zip pouch, connections made with wago type connectors, which come in 2,3 and 5 wire versions. The microswitches need a bit more insulting tape but it's a bit wet at the moment. Also fitted front light, horn and USB socket. The feed from the battery is fused and switched, switch hides in phone bag so nobody can mess with it when parked up.