Topic: Battery to Relay to Headlight: Shopping List?

[Mod Newb]

After a series of unfortunate events, I need to replace my headlight and bucket.  Most of the replacement headlights I've found include an "upgrade" to a H4 Halogen lamp.  I'm interested in the brighter headlight, but I'm not interested in spending the big bucks to go to an H.I.D. light. 

Regardless, I want to install the Battery-to-Relay-to-Headlight wiring modification.  I've found a wiring digram here: 

http://www.tekwyze.com/headlamp.pdf

However, I am a clueless idiot about this stuff.  I mean, clueless.  But I'm willing to experiment and learn, with the help of the wonderful SOHC4 forums.  I think I understand the basic idea of how to wire this up, but I'm not sure on the actual process.  For instance, what do I do for connections of the wire to the terminals on the relay?  What guage of wire should I get?  What relay should I look for?  So I've put together a basic shopping list:

- Relay 1 - what type?
- Relay 2 - what type?
- Headlight (55/65 H4 Halogen)
- 20A fuse
- fuse housing (do they make these "in-line"?)
- ?? ga wire (red) from Battery Positive Terminal to fuse
- ?? ga wire (red) from fuse to Relay 1, Terminal 30
- ?? ga wire (red) from Relay 1, Term 30 to Relay 2, Term 30
- ?? ga wire (yellow) from Relay 1, Term 87 to Headlight High Beam
- Existing wire from High Beam control switch to Relay 1, Term 85 (right?)
- ?? ga wire (blue) from Relay 2, Term 87 to Headlight Low Beam
- Existing wire from Low Beam control switch to Relay 2, Term 85 (right?)
- ?? ga wire (black/ground) from Relay 2, Term 86 to Relay 1, Term 86
- ?? ga wire (black/ground) from Relay 1, Term 86 to Headlight Ground
- ?? ga wire (black/ground) from Headlight Ground to Battery Negative Terminal
- 2 wire connections to battery terminals (soldering?)
- 8 single wire connections to relay/headlight terminals (soldering?)
- 3 double wire connections to relay/headlight terminals (soldering?)

Please, please, please forgive my stupidity. 

[Zaipai]

Yea I had the same questions. Mod, Also one more if I may, I assume (big mistake) that this would work with a CB550 and what does this do for you exactly? Brighter bulb? Less work for the alternator?

[kpier883]

Relays can be NAPA brand - Echlin AR143.  They are 6 bucks or so.  There is a fuse holder available at many NAPA stores as well, but I don't have a number.

[beta1042]

Lots of good info here: http://forums.sohc4.net/index.php?topic=45894.0

It would be nice to see a complete diagram with "required" wire sizes.

[motorhead55]

I found this on another posting here. Looks like a great set-up for the $$.
http://easternbeaver.com/Main/Products/H4_Kits/h4_kits.html

[MoTo-BunnY]

Here is a couple of wiring diagrams I used for using a relay on my horn upgrade, so you know what the connections on the relay and what they do. I used an extra VW relay I had extra from my Jetta. Generic relays are easily obtainable at auto parts places for like $5, though. Also, the same numbering system (86, 85, 87, etc.) seems to be used on all of them (from what I saw) for whatever reason.

[odin836]

Yes, what exactly is the benefit of this mod?

[Mod Newb]

Yea I had the same questions. Mod, Also one more if I may, I assume (big mistake) that this would work with a CB550 and what does this do for you exactly? Brighter bulb? Less work for the alternator?

I am obviously no expert, but I have read on other threads that this will work for the other SOHC4's as well.  From what I understand, this mod will get you more power at the headlight (resulting in a brighter light or louder horn) because it doesn't lose voltage through resistance in all of the extra wiring and switches it would go through in the stock wiring route.  I don't think this makes things any easier on the alternator.  You would still be using juice from the battery, so the alternator would still have to work to keep the battery charged.  This mod just gives a "shorter" route to the headlight.

I found this on another posting here. Looks like a great set-up for the $$.
http://easternbeaver.com/Main/Products/H4_Kits/h4_kits.html

I saw those too...I'm just hoping to do this on the cheap, and maybe force myself to learn something about wiring along the way.

One of the big remaining questions I have is how I should approach doing all of the wiring connections.  My preference would be to get some sort of mechanical connection to just plug onto the relay, headlight, and battery.  I mean, I'm sure tht I could learn how to solder, but I'm also that it will take some practice and I will screw some things up along the way....  Can you buy something (like Posilock connectors) that will make clean, tight, solderless connections?

[mystic_1]

This mod also reduces the current running through your handlebar switches, with associated benefits.


IMO there's no replacement for a good solder joint.  You'll need to do so in order to connect terminals to the ends of the wires anyhow.  Soldering iron kits are cheap, and the process is easy once you learn it.  Do some Googling, there's tons of info out there.  Main tip is to heat the wire with the iron and then apply the solder to the hot wire, don't apply the solder to the iron.

mystic_1

[Zaipai]

I am obviously no expert, but I have read on other threads that this will work for the other SOHC4's as well.  From what I understand, this mod will get you more power at the headlight (resulting in a brighter light or louder horn) because it doesn't lose voltage through resistance in all of the extra wiring and switches it would go through in the stock wiring route.  I don't think this makes things any easier on the alternator.  You would still be using juice from the battery, so the alternator would still have to work to keep the battery charged.  This mod just gives a "shorter" route to the headlight.

Thanks for the info. I will sure do this then. Perhaps that kit.. When it comes to wiring I really don't want to chance messing it up when there is these kits that have a better wiring job.
Scott..

[Mod Newb]

OK, after some additional reading and help from your comments, I have amended my shopping list:

- 10 ga wire (red)
- 10 ga wire (ground - green)
- 10 ga wire (high beam - blue)
- 10 ga wire (low beam - white)
- 15-16 ga wire (ground - green)
- 15-16 ga wire (high beam - blue)
- 15-16 ga wire (low beam color - white)
- (2) 12v automotive style relays: Bosch automotive relay or Napa - Echlin AR143
- (2) battery terminal crimp connectors
- Fuse holder
- 20A Fuse
- Cheap 30-40w pencil soldering iron w/ chisel tip
- Rosen core solder - 60% tin 40% lead, 0.062" diameter
- scouring pad (for cleaning iron tip after tinning)
- 3rd hand tool
- Patience

Another quick question:  Where's the best place to buy all of this stuff?  The local Pep Boys and Murrays auto parts stores are #$%*e for this kind of thing (at least, around where I live).  Should I hit a Home Depot?  Lowe's?  Ace?  Napa?

Anyway, this project seems pretty straight forward, and hopefully I'll learn enough (about soldering at least) to feel a little more confident on future wiring mods.  Thanks for the help.

Maybe if I get motivated enough, I'll post some pics of the entire process.  But it's going to be a while.