awesome article on elecrical

[graybird78]

this is a good tech article on 12 volt charging systems. could we adapt this to our bikes.



http://www.madelectrical.com/electrical-tech.shtml



graybird78

[pathfinder]

Electrical Gurus

I just read the tip about brighter headlights by using a relay. One of you electrical guys out there needs to figure out how to do it on a 78E. I've got one and would be happy to do the experiment and buy all the stuff if somene could give me directions that make sense to a non electrical guy like me. I never read directions untill after I have broken it but I promise I'll follow yours to the letter.

[Bud Manley]

From what I see all they do is wire the light direct to the alternator.
Relays are used for electrical control from one circuit to another, for instance,
I can use a 24 volt dc relay and switch to turn on 110vac lights and what not's. those are very common in electrical automation he must be moving the headlight to another circuit or creating a new one without any loads. Electrically all he is doing is adding an extra power consuming device to the existing system.

[fredintoon]

Fatter wire

Hi Bud,
Relay works on the starter, don't it? Same deal should improve headlamp voltage.
seems to me they were running fatter wires directly from the main power bus to the lamps and switching it with a relay triggered by the original skinny wires from the switch. Seein' as the XS11 has 16ga wiring intead of 12ga and teentsy little contacts in the switches to boot relays may well work if it's done right and you can find a place to put 'em. A concern I would have is bulb longevity. A bulb that's lasted quite a while getting only 11V might not take kindly to being fed 13V.
Fred Hill, S'toon.

[Hobbit]

Ohm's law

The gauge of the wire does not determine how much voltage a consumer receives. The charging system and battery are the only items that regulate how much voltage is available. If all of the connections are clean, each circuit receives the full voltage.

Poor connections act like consumers and use some of the voltage before it gets to the intended consumer.

The wire size is deterimined by how much amperage the consumers require to operate. Which is determined by the resistence of the consumer.

Example: The headlight receives a full 12volts and when lit has about 2 ohms of resistence, therefore it uses 6 amps, and can operate with a smaller gauge wire.

The starter motor receives a full 12volts, but when spinning only has about .2ohms and will need a wire large enough to carry 60 amps.

A relay is just a switch that has the ability to handle high amp loads while being operated by a low amp switch, otherwise your starter button would need to have the large wires running from the battery to the starter.

[fredintoon]

Ohm's law indeed

Hi Walt,
You and Mr Ohm both say, long skinny wires and poor contacts eat Volts. That's why the average headlamp is robbed of a Volt or so by the time the current gets to it.
That's why a relay, which as you say, is just a big fat set of remotely operated contacts, when used in conjuction with short lengths of heavy gauge wire, has less resistance than long skinny wires and teentsy contacts so the headlamp will see a higher Voltage and shine brighter in consequence.
Provided it's done right.
Fred Hill, S'toon.

[Hobbit]

Not quite

A skinny wire only causes a voltage drop if too much amperage is required at the consumer, then the skinny wire gets hot, which in affect, makes it a consumer (meaning that it now requires voltage to push the electrons through)! Then the real consumer can't get either the correct voltage or amperage. As the total circuit resistence goes up, the total amperage drops.

That's how you can have melted wires and even electrical fires yet never blow a fuse.

[nashville_bill]

AWG 16 wire has 4.2 Ohms per 1000 feet and .042 Ohms per 10 feet as compared to AWG 12 wire at 1.7 Ohms per 1000 feet or .0085 Ohms per 10 feet. At 12 Volts, the AWG 16 wire would drop about 0.22 Volts as compared to the AWG 12 wire at 0.1 Volts.

The voltage drops of the other devices in the lighting circuit could possibly make it worthwhile to change to a relay, but the wire size, at only a 0.12 Volt gain, would not really make a difference.

[Hobbit]

Actually, adding a relay increases the total amperage load on the charging system. Not only would you need power for the consumer but you also need power for the relay. The relays that I've tested that are strong enough to handle the amperage of a headlight circuit draw about .5 amps.