BMW Luxury Touring Community banner
1 - 20 of 28 Posts

·
Registered
Joined
·
1,304 Posts
Discussion Starter · #1 ·
OK guys, I'm looking for a critique or suggestions for future mods. I do have a flamesuit handy so have at it. I thought of a new way (for me anyway) of splicing into an existing wiring harness. I sliced off half of the insulation on the wire in question with an Exacto knife to approx. 1/4". I then lifted about half the strands of wire and inserted the end of the wire to be spliced in that space. I then soldered the connection, painted it with liquid tape then covered it with a piece of silicone rubber tape (rescue tape). What do you think of this method and do you have another/better way? I was doing this to install a weatherproof Garmin power supply under the handlebar shroud. See pics. Flame away.

Robert



 

·
Registered
Joined
·
876 Posts
Looks fine to me, and will tidy up nicely when covered. I too like to use solder on any splices or connections, the trick being to have a neat little soldering iron. I tend to use a little silicon between the branch wires before wrapping with tape, just to keep any moisture out. Good job !
 

·
Registered
Joined
·
2,746 Posts
Your technique is perfectly acceptable. The key is to have a good mechanical connection (you do) then heat the splice adequately and let the solder flow into the joint. (It did.) A quality joint that won't fail will be shiny and smooth. (Yours is) Great job.

Loren
 

·
Premium Member
Joined
·
177 Posts
Remembering back to my vo-tech school days, the strongest joint comes from mechanically twisting the wires prior to applying the solder. In practice, that is easier said than done. Even when I attempt it, most times I only get half a twist with no real mechanical strength.

I think it will probably hold up fine, particularly with the rescue tape.

Jim H.
 

·
Premium Member
Joined
·
2,967 Posts
+1 one the comments of a mechanical connection first. The solder carries the voltage & current and is not designed to provide mechanical strength.

Heat the wires from the underside and flow the solder from the top. The solder should completely flow through the joint. Do not disturb as it cools. The joint should be very shiny after you remove the heat source.

If not it is a cold joint and will fail with vibration stress.



N8QZ
(lots of home brew-projects with irons, pencils and solid state soldering stations)
 

·
Premium Member
Joined
·
3,108 Posts
I do basically the same thing but just use my wire strippers to cut the insulation and then simply slide it back rather than removing any. After soldering I tape wrap and then zip-strip the tape in place.
 

·
Enjoy The Ride
K1300GT K1200LT
Joined
·
4,069 Posts
I don't solder anything on vehicles unless I absolutely have to. If I do have to solder something I pot it with epoxy past the solder to where the wire can flex. I use crimp connectors so the wire can flex. Solder connections are stiff & can break the wire at the end of the solder.
 

·
Super Moderator
Joined
·
1,433 Posts
Soldering the wires and the follow up securing of the wires in the manner you described is
perfectly fine for your application. Soldering offers a superior electrical connection for
motorcycles that are open to the environment and resists further corrosion unlike many
mechanical connections. :cool:
 

·
Registered
Joined
·
2,746 Posts
If the wires are secured so they don't flex they wont break. No mechanical connector can beat a soldered connection. Soldered connections won't corrode, seperate, or come apart. As permanent a connection as you can make.

Loren
 

·
Registered
Joined
·
3,277 Posts
Similar to how I've had to do a few joins.... where I know for certain that I (or a stealer) won't have to split those wires to take any tupperware apart or remove parts now attached by wires.
Only other comment is on wire colours... green to red? I'd have to assume (without looking it up) that the green is power?
 

·
Registered
Joined
·
498 Posts
dfinazzo said:
Soldering the wires and the follow up securing of the wires in the manner you described is
perfectly fine for your application. Soldering offers a superior electrical connection for
motorcycles that are open to the environment and resists further corrosion unlike many
mechanical connections. :cool:
+1
 

·
Premium Member
Joined
·
4,897 Posts
Some nice solder tips from years of experience.

The only soldering on my K1200LT involved the AutoComm installation for the speaker wires and I wish I had had the above tips. It all worked out OK but these tips would have made the job a little better.

Lately though, I have been using Posi Taps on all wiring projects. They allow me to make mistakes and easily correct them. When I use the correct size, it is easy, quick and seems to work well.
 

·
Registered
Joined
·
4,404 Posts
I agree with all the above posts, including Saddleman's admonition about solder joints being at increased risks for fatigue fracture. That said, many of the cheaper crimp connectors will oxidize over time and the circuit may become "flaky" due to varying resistance or open circuit. A properly soldered connection is excellent as long as the joint is isolated from vibration. A quality crimp connector can also be an excellent connection if done properly and protected from oxidation with dielectric grease. The non-soldered crimp connection is a better choice where the joint cannot be isolated from movement.

Solder joints should be stabilized to prevent flexing. The wire gets brittle from the heat during the solder process and can eventually break right next to the solder joint if flexing occurs.

What you have pictured will work.
I prefer heat shrink tubing for insulation over liquid tape or wrapped tape. I would have cut the OEM wiring right through and slid a piece of heat shrink tubing onto one end of the cut wire far away from the intended solder joint so the heat of the soldering process wouldn't affect the heat shrink tubing. (make sure the section of heat shrink tubing is long enough to overlap the wire's insulation on both sides of the solder joint. too long is better than too short.)

I would then strip the ends of the OEM wiring and twist them together along with the wire being spliced in. If additional length were needed because the existing OEM wire was run so tight that a half inch of overlap of the original wire ends could not be obtained, I would not hesitate to splice in a short length by stripping the wire being spliced in for a greater length to close the gap between the OEM wire ends.

After twisting the wires together for a good mechanical connection, solder a nice shiny connection. Too little heat or movement of the joint before it cools will cause the solder to be dull; referred to as a "cold solder joint", this will lack good electrical conductivity and be mechanically weak. Too much heat will unnecessarily weaken the wire adjacent to the solder joint, increasing brittleness, resistant to current, and breakage. Unnecessarily "cooking" the wire during soldering will increase resistance in the wire and depending on current loads, over time that increase in resistance will result in current continuing to "cook" the wire.

Once the joint is soldered, the heat shrink tubing is slid over the joint and mild heat applied to the tubing to shrink it.
 

·
Registered
Joined
·
1,304 Posts
Discussion Starter · #15 ·
cws said:
Similar to how I've had to do a few joins.... where I know for certain that I (or a stealer) won't have to split those wires to take any tupperware apart or remove parts now attached by wires.
Only other comment is on wire colours... green to red? I'd have to assume (without looking it up) that the green is power?
The green/violet is switched power from the load shed relay. Red is what came with the Garmin power supply. All connections are under the handlebar shrouds.

Robert
 

·
Registered
Joined
·
1,304 Posts
Discussion Starter · #16 ·
CharlieVT said:
I agree with all the above posts, including Saddleman's admonition about solder joints being at increased risks for fatigue fracture. That said, many of the cheaper crimp connectors will oxidize over time and the circuit may become "flaky" due to varying resistance or open circuit. A properly soldered connection is excellent as long as the joint is isolated from vibration. A quality crimp connector can also be an excellent connection if done properly and protected from oxidation with dielectric grease. The non-soldered crimp connection is a better choice where the joint cannot be isolated from movement.

Solder joints should be stabilized to prevent flexing. The wire gets brittle from the heat during the solder process and can eventually break right next to the solder joint if flexing occurs.

What you have pictured will work.
I prefer heat shrink tubing for insulation over liquid tape or wrapped tape. I would have cut the OEM wiring right through and slid a piece of heat shrink tubing onto one end of the cut wire far away from the intended solder joint so the heat of the soldering process wouldn't affect the heat shrink tubing. (make sure the section of heat shrink tubing is long enough to overlap the wire's insulation on both sides of the solder joint. too long is better than too short.)

I would then strip the ends of the OEM wiring and twist them together along with the wire being spliced in. If additional length were needed because the existing OEM wire was run so tight that a half inch of overlap of the original wire ends could not be obtained, I would not hesitate to splice in a short length by stripping the wire being spliced in for a greater length to close the gap between the OEM wire ends.

After twisting the wires together for a good mechanical connection, solder a nice shiny connection. Too little heat or movement of the joint before it cools will cause the solder to be dull; referred to as a "cold solder joint", this will lack good electrical conductivity and be mechanically weak. Too much heat will unnecessarily weaken the wire adjacent to the solder joint, increasing brittleness, resistant to current, and breakage. Unnecessarily "cooking" the wire during soldering will increase resistance in the wire and depending on current loads, over time that increase in resistance will result in current continuing to "cook" the wire.

Once the joint is soldered, the heat shrink tubing is slid over the joint and mild heat applied to the tubing to shrink it.
I agree with everyone on the solder being hard and any flexing of the wire will eventually break the wire next to the solder. I have experienced this in the past. I also agree about the heat shrink, I must have 200 feet of it in various sizes and colors in my shop and use it all the time. I consider the Rescue Tape to be a heat shrink that you can wrap around wires. After it cures you have to cut it off. This particular application should have zero wire movement as all wires are captured and tied to the handlebars. My purpose for just shaving off the top of the insulation was to leave the majority of the insulation to retain as much integrity of the factory wire as possible while still achieving my goal of a hard wired GPS power source. I really appreciate everyone's comments and techniques. I will file all of these in my brain for future use.

Thanks, Robert
 

·
Registered
Joined
·
1,304 Posts
Discussion Starter · #17 ·
DanDiver said:
Some nice solder tips from years of experience.

The only soldering on my K1200LT involved the AutoComm installation for the speaker wires and I wish I had had the above tips. It all worked out OK but these tips would have made the job a little better.

Lately though, I have been using Posi Taps on all wiring projects. They allow me to make mistakes and easily correct them. When I use the correct size, it is easy, quick and seems to work well.
I bought some Positaps but hesitate to use them since the tapped wire must be 90 degrees to the original wire and would cause clearance issues on this particular project. Have you had any issues with the Positaps loosening over time? I curious about the long term reliability. They are certainly a good idea, especially if they work well.

Thanks, Robert.
 

·
Registered
Joined
·
576 Posts
Another thing that hasn't been brought up yet:

Invest in a small butane soldering iron.
- no cables
- no power (use it on the road!)
- the exposed area where the catalyst is exposed to air is GREAT for shrinking heat-shrink
- did I mention no cables?

And be sure to keep your tip tinned and a moistened sponge nearby to clean it off.
 

·
Premium Member
Joined
·
4,886 Posts
Rocketsled said:
Another thing that hasn't been brought up yet:

Invest in a small butane soldering iron.
- no cables
- no power (use it on the road!)
- the exposed area where the catalyst is exposed to air is GREAT for shrinking heat-shrink
- did I mention no cables?

And be sure to keep your tip tinned and a moistened sponge nearby to clean it off.
+1

I have a handy one from Rat Shack that had the sparker built into the cap. Under $50 IIRC.
 

·
Registered
Joined
·
1,304 Posts
Discussion Starter · #20 ·
Spenceer said:
Is the wire sized correctly for the load?

3M makes some very good splicing devices for that job.
The load is very slight. It is powering a USB device. I am guessing in the 100-200 milliamp range although I have not been able to find the current draw of a Nuvi 550. So in answer to your question "I think so." What type of 3M connectors are you referring to? Model/part #?

Robert
 
1 - 20 of 28 Posts
Top