Headlight Power Wire 75' CB550f

[henndoe]

Hi guys - I'm looking to wire in a toggle kill switch for the headlight on my 75 550f in order to save some power during daytime. I'm very new to electrics so go easy.
I've taken a look at the 550f wiring diagram, and to me it appears that there are 3 wires running to the headlight. Blue which routes to the high beam switch and indicator light, white, which routes to the low beam switch, and green. I've been told green is always ground on hondas, so in this case, which wire is power?
I'm thinking in just wiring in a toggle switch to the power wire, would this be wrong? ???

Thanks very much.

 

[Toast]

I guess depending on where you plan on putting the headlight kill switch, you could add an on/off switch on the headlight bucket and use it to open/close the headlight ground. Switching the headlight power to the switch works too, I'd think there would be less easy to reach places to put it though.

 

[henndoe]

I guess depending on where you plan on putting the headlight kill switch, you could add an on/off switch on the headlight bucket and use it to open and close the headlight ground.

Yeah I was planning on adding the headlight kill switch on the side of the headlight bucket. I'm just worried that the ground (green wire) looks like it's part of a larger circuit in the diagram. So would opening/closing the headlight ground effect other things wired to the green wire?

 

[dualitymike]

The blue wire and the white are both power wires. The best choice here is to put the switch on the green wire. It's not in series with any other components so you won't be shutting off anything else if you defeat the headlight ground. Just don't forget to turn it on at dusk so people can see you coming.

 

[Toast]

The ground cable coming from the headlight plug eventually does plug into the harness's main ground wire, but according to the schematic nothing else is tied into that particular line.

 

[henndoe]

The ground cable coming from the headlight plug eventually does plug into the harness's main ground wire, but according to the schematic nothing else is tied into that particular line.

Excellent, I appreciate the help.

 

[henndoe]

The blue wire and the white are both power wires. The best choice here is to put the switch on the green wire. It's not in series with any other components so you won't be shutting off anything else if you defeat the headlight ground. Just don't forget to turn it on at dusk so people can see you coming.

Thanks!

 

[Bert Jan]

First - why do you need extra juice? A new battery is never a bad idea. Check for current at battery with engine @3500 RPM. Should be above 13v. Do not fix something that is not broken.

ontopic, regarding other answers;
That won't do i guess. The bulb touches the headlight-bucket, wich is grounded aswell. The ground wire is an extra precaution. You could do the switch on the blue wire alone. That way, you'll have low-beam or no beam during daytime. Better yet is to unplug the blue wire and cap it off. Only problem is you do not longer have a high-beam. Big advantages are it's a 1 minute job, no $$, no switch to solder/crimp (ahum), no holes to be drilled for switch and easy to reverse.

If your loom is original, please don't cut it up but get correct plugs and wires (right color!!). If you choose later on to turn it back to stock, it's easy. Electrics are black magic. Do it right or do not do it at all. Even a simple wire can cause problems in the future. If you choose to do a switch, get one with more amps than your battery. Headlight gets the full shabang. 25amp would be nice.

 

[Bert Jan]

I guess depending on where you plan on putting the headlight kill switch, you could add an on/off switch on the headlight bucket and use it to open/close the headlight ground. Switching the headlight power to the switch works too, I'd think there would be less easy to reach places to put it though.

No, also no go. The switch on the handlebars control more stuff on the bike. When you shut off power to the switch, all options are dead for that switch. DO NOT DO THAT.

Again, fiddling around with electrics on cb's is not really a good idea - it's delicate and balanced 30 year old crap. Only do it if it's broken and/or if you know what you're doing. You'll come to understand me when you open the headlight bucket.

 

[dualitymike]

First - why do you need extra juice? A new battery is never a bad idea. Check for current at battery with engine @3500 RPM. Should be above 13v. Do not fix something that is not broken.

ontopic, regarding other answers;
That won't do i guess. The bulb touches the headlight-bucket, wich is grounded aswell. The ground wire is an extra precaution. You could do the switch on the blue wire alone. That way, you'll have low-beam or no beam during daytime. Better yet is to unplug the blue wire and cap it off. Only problem is you do not longer have a high-beam. Big advantages are it's a 1 minute job, no $$, no switch to solder/crimp (ahum), no holes to be drilled for switch and easy to reverse.

If your loom is original, please don't cut it up but get correct plugs and wires (right color!!). If you choose later on to turn it back to stock, it's easy. Electrics are black magic. Do it right or do not do it at all. Even a simple wire can cause problems in the future. If you choose to do a switch, get one with more amps than your battery. Headlight gets the full shabang. 25amp would be nice.

The headlight is not grounded to the headlight bucket. That's absurd. The part of the headlight ring that touches the bulb touches glass only which is not comductive. Furthermore, the bucket itself is plastic. The headlight is grounded through the green wire only.

As for needing extra juice, the Cb550 charging system is notoriously enimic. Testing at 3500 rpm will show 13 volts or more, but if you're driving in the city, every time you idle at a light, you're draining the battery. I've done all the math. It's a good idea to conserve power where you can.

 

[dualitymike]

Here's a quote from TwoTired on this site:

Some basics. The 550 has a 150 watt peak alternator output. It can only produce this much power if it's magnetic field is driven to full strength AND the rotor is spinning fast enough.
At idle and with full field strength, the alternator can only make about 1/3 of peak capability, or about 40-50 watts.
The stock bike (you never told us if your bike was stock, electrically) consumes about 120 watts whenever the key switch is in the ON position. What isn't produced from the alternator is drawn from battery storage until it is depleted.

 

[Bert Jan]

The headlight is not grounded to the headlight bucket. That's absurd. The part of the headlight ring that touches the bulb touches glass only which is not comductive. Furthermore, the bucket itself is plastic. The headlight is grounded through the green wire only.

As for needing extra juice, the Cb550 charging system is notoriously enimic. Testing at 3500 rpm will show 13 volts or more, but if you're driving in the city, every time you idle at a light, you're draining the battery. I've done all the math. It's a good idea to conserve power where you can.

Some cb's have metal buckets. TS did not mention anything about that, i therefor suggested to take out the power earlier, just to be safe and furthermore, have some lights when needed (passing/danger/sign) in a hurry.

I know glas is not conductive.

When he has the original battery, there is no need for diy-upgrades. No point. The battery is 12amp, more then capable enough.

Conserving power is a good idea up to a certain point. If you won't take any power you're giving the rectifier a hard time.

CB550 can idle for 30 minutes without any problems. I've been experimenting with the cb550 charging for some time now, even rode a cb550 without rotor around town with a 2ah battery for roughly 40 minutes, just to check. Took another battery with me to get 'er home.

Now, if the headlight is plastic, you can take out the ground wire with a switch, so thats my bad in that case.

 

[dualitymike]

Some basics. The 550 has a 150 watt peak alternator output. It can only produce this much power if it's magnetic field is driven to full strength AND the rotor is spinning fast enough.
At idle and with full field strength, the alternator can only make about 1/3 of peak capability, or about 40-50 watts.
The stock bike (you never told us if your bike was stock, electrically) consumes about 120 watts whenever the key switch is in the ON position. What isn't produced from the alternator is drawn from battery storage until it is depleted.

 

[dualitymike]

Didn't mean to step on any toes. I've owned a CB550F for 20 years and believe me, even with a tip top charging system, the battery takes a beating in stop and go traffic. Another issue is that the stator on that model uses electro magnets so if the battery isn't strong enough to power the magnets properly, the stator can't operate at optimal levels, causing a cascade of sorts. So I agree a very good battery IS a good idea, but when you consider your headlight is drawing 55 watts on low beam and the alternator is only putting out 40w - 50w at idle, the advantages of saving power are real.

 

[dualitymike]

I know. But thanks for posting it twice i guess.

My computer is crap. It keeps giving me errors saying the post didn't work. Posting twice was unintentional.

 

[Bert Jan]

Didn't mean to step on any toes. I've owned a CB550F for 20 years and believe me, even with a tip top charging system, the battery takes a beating in stop and go traffic. Another issue is that the stator on that model uses electro magnets so if the battery isn't strong enough to power the magnets properly, the stator can't operate at optimal levels, causing a cascade of sorts. So I agree a very good battery IS a good idea, but when you consider your headlight is drawing 55 watts on low beam and the alternator is only putting out 40w - 50w at idle, the advantages of saving power are real.

No problem. I like to learn, not be lectured, that's all

I know the field-rotor principle can be a pain when you try to start the old girl with a flat battery....

 

[Bert Jan]

My computer is crap. It keeps giving me errors saying the post didn't work. Posting twice was unintentional.

Mine does aswell. incorrect value added or sum?

 

[dualitymike]

Ya, same thing.

btw - I'm working on an LED headlight idea for my CB550. I don't thin it's DOT approved but I'm going to give it a try anyway. The LED I'm thinking of using is a 20w that puts out over 1000 lumens. The high beam on the stock headlight puts out 840 lumens or so and draws 60w. I'm going to build a pulse width modulator to dim the LED for low beam. I'll post a build thread once I get started on it.

May not work, but it's worth a try.

Mike

 

[Bert Jan]

sounds good, keep us posted!

 

[henndoe]

Ya, same thing.

btw - I'm working on an LED headlight idea for my CB550. I don't thin it's DOT approved but I'm going to give it a try anyway. The LED I'm thinking of using is a 20w that puts out over 1000 lumens. The high beam on the stock headlight puts out 840 lumens or so and draws 60w. I'm going to build a pulse width modulator to dim the LED for low beam. I'll post a build thread once I get started on it.

May not work, but it's worth a try.

Mike

Interested in see this. Keep us posted!

In response to the headlight bucket issue: I know that it's not the best idea to mess with a stock charging system, but I really need to save the power. I'm running a new battery (put in by the previous owner) so the voltage on that sucker is good. The main issue is that I have to switch to turn my headlight off, and it really drains power - which leads to issues like a weak starter motor, and makes starting the bike difficult. I really don't need it in the daytime, and I need any extra power gain-age that I can get. I'm also planning on eliminating some other components (gauges, indicator lights - except for oil and neutral safety switch. These are for aesthetics mainly).

As for where I'm at: It seems that either Bert Jan's idea about wiring a switch on the blue wire, or dualitymikes idea about the switch on the green, ground wire makes the most sense right now - in terms of simplicity and ease of access.
I'm open to any objections to this idea - I want to do this right.

Thanks guys.