Author Topic: dual headlight question (Read 4272 times)

nokrome · « **on:** August 19, 2009, 06:41:06 PM »

i want to run a dual headlight setup on my 750 project, the bulbs are 60/55 watts (two total), i will also be running an oregon motorcycle parts reg/rec. i was told that the electrical system will not handle the load but i want some more opinions
thanks

TwoTired · « **Reply #1 on:** August 19, 2009, 06:53:30 PM »

Stock alternator makes 210 watts at 5000 RPM, 50-ish watts at idle.

Stock bike uses about 120-130 watts on average. Stock headlight 50/40 Watts.
Add 70 watts to 130 and you get a 200 Watt load.

Just keep your idle at 5000 RPM and you should be fine. Won't even need a regulator, as 10 watts is unlikely to over charge the battery.

MCRider · « **Reply #2 on:** August 19, 2009, 08:03:59 PM »

Maybe run 2 switches so you can kill one at idle. Or during daylight when you don't need it anyway.

DavePhipps · « **Reply #3 on:** August 19, 2009, 08:06:08 PM »

Is there an alternator upgrade that he can use?

Inigo Montoya · « **Reply #4 on:** August 20, 2009, 06:04:51 AM »

I doubt the alt can be upgraded so to speak but I wouldnt doubt it if it could be rewound to provide a little extra output.
Another option is a cyclex charging system. That might work too.

MCRider · « **Reply #5 on:** August 20, 2009, 06:32:47 AM »

Quote from: vinmans brew on August 20, 2009, 06:04:51 AM

I doubt the alt can be upgraded so to speak but I wouldnt doubt it if it could be rewound to provide a little extra output.
Another option is a cyclex charging system. That might work too.

I've been looking for a rewind, no luck yet.

And the CycleX system sacrifices the electric starter. Which isn't the end of the world to me, but for some it might be.

nokrome · « **Reply #6 on:** August 20, 2009, 07:17:18 AM »

i like the cycle x system but im already too far along and over budget on the project for that to be an option,
i was thinking about using some lower wattage bulbs but i think that 60/55 is as low as you can get in an h4 (is that true?)
i might just have to ride around with only one headlight that actually works

doobiebro · « **Reply #7 on:** August 20, 2009, 07:20:36 AM »

I have considered dual headlights just to be a little different from others with my '77 750K. I read several older posts on this and it seems to be the consensus that there are some options, but overall the 750 cannot handle the extra draw.

However, I have a thought to ponder. If you add a drop down transformer in the headlight circuit to reduce the voltage from 12 volts to 6 volts, could you then use two 6 volt headlights? I have seen some halogen 6 volt lights on the internet and was wondering if they would be bright enough. My thought is, although I get confused with the mathematics, with the transformer two 6 volt 55 watt lights may draw the same current as one 12 volt 55 watt light. Is this possible?

MCRider · « **Reply #8 on:** August 20, 2009, 07:21:14 AM »

Quote from: nokrome on August 20, 2009, 07:17:18 AM

i like the cycle x system but im already too far along and over budget on the project for that to be an option,
i was thinking about using some lower wattage bulbs but i think that 60/55 is as low as you can get in an h4 (is that true?)
i might just have to ride around with only one headlight that actually works

If its light that you want, a single 60/55 with a relay is pretty darn good. Make sure all your harness connections are clean and tight. From the alternator up and from the battery down.

A second switch for the second light still sounds good to me. I don't think you'd run two lights thru the stock switch, without a relay, without smoking the switch.

kenolds · « **Reply #9 on:** August 20, 2009, 08:18:29 AM »

1) P= V^2 / R
2) R= V^2 / P
3) I = V/R

Where P is power in watts, V is volts DC, I is current in Amps, R is resistance in Ohms.

A light bulb is a resistor. If you have a 50 Watt /12Volt light it is a 2.88 ohm resistor (equation 2). That resistor in a twelve volt circuit will use 4.17 Amps (equation 3). In a 6 volt circuit it will use half the current (2.08 amps - equation 3). Sounds good so far - but here's the bad news. From equation 1 we see that our 50 watt bulb is now only consuming 12.5 watts. It will be 1/4 as bright as it was at 12V (assuming light output is proportional to wattage for a given bulb type). The moral of the story is...the alternator puts out a certain amount of power. Changing the voltage cannot give you more power. You could step down the voltage some to be able to run the two headlights, but they would not produce any more light than a single bulb. If you want to run them both, do a little experiment to see how bright they are at your reduced voltage. Have you considered HIDs? They are more like 35 watts.

Kenolds

honda750k · « **Reply #10 on:** August 20, 2009, 08:29:47 AM »

I would think that HID would be a viable alternative, and you can get that in an H4 setup. if memory serves correct, HID only requires like 35 watts in functional mode.

bistromath · « **Reply #11 on:** August 20, 2009, 08:34:50 AM »

The HID suggestion is a good one. One 35 watt HID would be brighter than the 55/60 halogen. Two 35 watt HIDs would light up the surface of the Moon.

As far as transformers, they only work on AC. If you want to run two headlights at 6V apiece, just wire them up in series. Same deal regarding wattage applies, though: no sense running two 55W 6V lights in series, they'll still be sucking 110W out of your electrics. Kenolds's comment about running 12V lamps at 6V also applies, with one more negative: the cooler incandescent will now be radiating most of its energy in the long infrared, so you'll just see a dull orange glow anyway.

doobiebro · « **Reply #12 on:** August 20, 2009, 08:52:35 AM »

Thanks, Kenolds and Bistromath for the clarification. Your explanations help to understand the mathematics. Although I am okay with math, for some reason I was unable to process it in practical usage.

Inigo Montoya · « **Reply #13 on:** August 20, 2009, 09:18:53 AM »

I think the issue with HID lights is the size of the installation. They require a ballast unit. So you first have to find smaller buckets, as 2 large 7 inchers might look pretty dumb side by side, THEN you have to fit all the guts back in with the hid set up. I suppose an option would be to move the headlights a bit forward and make a small box to hold all the wiring and such but then you might want a fairing of some sort to cover it up.

bistromath · « **Reply #14 on:** August 20, 2009, 11:03:55 AM »

HID units for motorcycles have remote ballasts, which you can fit next to the coils or under the seat, sidecovers, etc.

nokrome · « **Reply #15 on:** August 20, 2009, 12:30:22 PM »

i checked out some hid kits, seems like alot of extra stuff that will need to be installed (x2)
im really hooked on the looks of this dual headlight setup, i dont think i can go back to a single light
the lights that i have both have a small running light in them as well as the h4 bulb, im leaning in the direction of just disconnecting one of the h4s and running the other one through a relay, it seems kind of cheesy to me but it doesnt look like i have many good options.
sombody told me that they converted a 35 watt h3 bulb to work in a h4 housing, anybody ever heard of this?

Rampage1967 · « **Reply #16 on:** August 20, 2009, 08:16:48 PM »

Will a 750 run two 45/45w bulbs??
If it will then www.candlepower.com has them.
I hear there is a 35/35w scooter H4 available, they turn up on ebay.
Those might get your current draw down on dual lights.

verboten1 · « **Reply #17 on:** August 20, 2009, 08:49:13 PM »

I want to see pics of the

dual headlight machine

MJL · « **Reply #18 on:** August 20, 2009, 09:10:22 PM »

Quote from: MCRider on August 20, 2009, 06:32:47 AM

Quote from: vinmans brew on August 20, 2009, 06:04:51 AM
I doubt the alt can be upgraded so to speak but I wouldnt doubt it if it could be rewound to provide a little extra output.
Another option is a cyclex charging system. That might work too.

I've been looking for a rewind, no luck yet.

And the CycleX system sacrifices the electric starter. Which isn't the end of the world to me, but for some it might be.

Does it? You can go batteryless, then there is no juice for the starter anyway. You don't have to ditch the battery and starter I don't think.

Zaipai · « **Reply #19 on:** August 20, 2009, 09:21:18 PM »

HID seems a good way to go. Have you looked into LED bulb replacements? Maybe they draw less? Might be worth checking out. Just my 2cents worth..

nokrome · « **Reply #20 on:** August 20, 2009, 09:53:30 PM »

thanks for the replies,

Quote from: Rampage1967 on August 20, 2009, 08:16:48 PM

Will a 750 run two 45/45w bulbs??
If it will then www.candlepower.com has them.
I hear there is a 35/35w scooter H4 available, they turn up on ebay.
Those might get your current draw down on dual lights.

i found the 35w h4 halogen on ebay, looks like those will do the trick, they are listed as 35/35w does that mean there is no high beam ?

Quote from: verboten1 on August 20, 2009, 08:49:13 PM

I want to see pics of the dual headlight machine

pics tomorrow, its still a work in progress but you will get the idea

Zaipai · « **Reply #21 on:** August 21, 2009, 07:06:56 AM »

Great, can't wait to see the pics. Yea it would seem that the high beam is just adding more light not a brighter light. Just a guess based on a setup like that a friend had once. Once you hook them up you will know for sure.

MCRider · « **Reply #22 on:** August 21, 2009, 07:17:55 AM »

Quote from: nokrome on August 20, 2009, 09:53:30 PM

thanks for the replies,

Quote from: Rampage1967 on August 20, 2009, 08:16:48 PM
Will a 750 run two 45/45w bulbs??
If it will then www.candlepower.com has them.
I hear there is a 35/35w scooter H4 available, they turn up on ebay.
Those might get your current draw down on dual lights.
i found the 35w h4 halogen on ebay, looks like those will do the trick, they are listed as 35/35w does that mean there is no high beam ?
Quote from: verboten1 on August 20, 2009, 08:49:13 PM
I want to see pics of the dual headlight machine
pics tomorrow, its still a work in progress but you will get the idea

Could be a different focus. High beams are usually straight ahead spots, low beams are near and spread.

Rampage1967 · « **Reply #23 on:** August 21, 2009, 11:54:55 AM »

Quote from: MJL on August 20, 2009, 09:10:22 PM

Quote from: MCRider on August 20, 2009, 06:32:47 AM
Quote from: vinmans brew on August 20, 2009, 06:04:51 AM
I doubt the alt can be upgraded so to speak but I wouldnt doubt it if it could be rewound to provide a little extra output.
Another option is a cyclex charging system. That might work too.

I've been looking for a rewind, no luck yet.

And the CycleX system sacrifices the electric starter. Which isn't the end of the world to me, but for some it might be.
Does it? You can go batteryless, then there is no juice for the starter anyway. You don't have to ditch the battery and starter I don't think.

According to CycleX web page it does not work with electric start. Also it's rated output is 14A, or about 190W.
that sounds about same as stock.

MJL · « **Reply #24 on:** August 21, 2009, 12:49:40 PM »

I don't see where it says it won't work with electric start.

Quote

"NEW" Cycle X charging system
* Single phase system allows battery or battery less operation. ( call for details )
* Rotor weighs only 1.640 lb's for high rev potential
* 14 amp system
* Kick only ( who needs a button anyway )
* Complete system weighs over 8 lbs less than a OEM system.

Note:
Honda's 3 phase field excited charging will create a magnetic pull when the regulator tells it.
This magnetic pull can reduce horsepower ( sometimes 2 horsepower )
Reduced rotating weight and less magnetic pull makes the Cycle X charging system the best choice.
Kit includes:
* 1.640 lb rotor
* 14 amp stator ( single phase ) and adaptor plate
* Crankshaft oil block-off sleeve ( Kick only )
* Crankshaft spacer.
* Starter hole block-off plug with fitting ( wires come out of this location)
* Solid state regulator-rectifier ( Made in USA )
* Gasket
* Instructions

$ 449.99 #CRG-1234

If you have a battery then what is stopping you from using a starter? A lot of cafe people want to shave off as much weight as possible, so in order to ditch the battery and starter they use this (have to as the stock rotor won't allow batteryless operation)

News:

Author Topic: dual headlight question (Read 4272 times)

Rampage1967

Rampage1967