Rugged Electric Vest Connections

From: Brian Curry <bmwbrian@voicenet.com> Tue Jan 14 00:31:21 1997
Subject: Rugged Electric Vest Connections

Most if not all, electric clothing users, by any manufacturer, have had problems with the connectors. They are one of the worst parts of them. They are cheap, even if the vest is first class and will survive a nuclear attack. As a 20 year electric vest user I have spent some time finding out what worked and what didn't. This is the summary of it extracted from a specific post to the IBMWR list.

IMO, the best thing you can do for _ANY_ vest's connectors is to convert them over to Radio Shack (RS) connectors. I have never had the RS connectors fail. I have had them lose pieces, crack and melt, but they kept on working. I don't have this happen any more, I have continually upgraded the connection.

The Radio Shack Part numbers are: Plug 274-201, Socket, 274-202. The connectors have cylindrical bodies and two flat blades, or slots respectively. This makes them "polarized" so they only go together one way. This can be good if you mount the same on your battery charger leads.

IMPORTANT!! USE ONLY SOCKETS TO SUPPLY POWER. These are the ends from the bike or on a jacket sleeve end. If you use a plug, sooner or later the prongs will touch ground. If it is fused, always a good idea, you will blow the fuse. If it is not fused, you can see arcs and sparks, and if you are really unlucky, a conflagration and a visit from the fire department. If an un-fused glove connection plug prong touched ground/the frame you could get some "interesting" branding, and might set record time getting out of your riding gear. :(:(

Here is how I use them. If you are solder phobic, find someone to do it for you.

First disassemble the shells and bodies. With pliers, and preferably needle nose pliers, remove the twist grip pin holding the shell to the plug body. The shell has two parts an inner press fit part and the outer part. Keep them together. Take out both screws holding the cable grips together.

                    Pins __|            |
                __=_____/  |            |
         Wire   __ _____   |            |
                  =     \__|            |
        Heat Shrink        |____________|
Get your wire. I like to use 16 gauge wire, but 18 gauge will work. The RS P/N's 278-1105, and 278-1103 respectively. Both are brown in color and the "short" length of 30 ft. (You will have a surplus coming out of this project unless you make _lots_ of mistakes!) (Don Eilenberger mentioned, that if you can find it, and especially if you are around a salt environment, "marine grade" wire is much better. All the conductors are individually tinned making them more corrosion resistant.) Slip a little bit ~1/4" or so of heat shrink tubing (RS has an assortment P/N 278 1627) onto the wire first. (Don't shrink it yet! Also, it while it is possible, to put it on after the shell and squoosh it down to fit between the wire and shell it takes a lot of patience and maybe a few beers, or you decide to take it all apart and do it right _again_. :(:( ) Push it away from the wire end. Slip the outer shells over the wire and push it away from the end. Split the cable just a bit ~1/4-1/2" Strip the conductor ends ~1/8 1/4" Tin the ends. Tin the connector pins. Solder wire to the connector pins. I don't twist the wire on the pins. I do a lap joint, (Put one by the other and heat.) there is plenty of strength here. I put the wires on the inner sides of the pins so there is minimum splitting. It does not matter which of the wires go on which pin. I use the convention of making the big pin, the positive connection.

Slide the shell over the plug body. Take one of the cable grips and slide it in the little slot in the shell. Mark where it contacts the wire. Remove the grip. Slip the heat shrink over the marked area. (You did put it on first didn't you?) Heat it and shrink it in that location. Paper matches will work. Wood matches are better. A candle has the best amount of heat and control IMO. Butane lighters will also work. Do not melt the wire or shell.

It may be possible to push the shell back over the heat shrink before it is shrunk. Or if the wire is premeasured, you can take everything off and then put the shell back on after the heat shrink is shrunk. The heat shrink does a few things. It keeps the wire from splitting more. It builds the wire up a bit so the cable grips can clamp it better. It keeps the grips from cutting through the insulation to the wire.

Slide the shell back on. Insert the twist grip pin holding the shell to the body. Put the cable grips on. I trim the screws but it is not critical. I put the grips on and lightly thread them in see how much I need to remove to have about 1/16-1/8" sticking out. I remove them, trim then and then put them in and snug them down. I then put RTV/silicone rubber/silicon caulk on the threads sticking out. (Note, any type of glue stuff would work, weatherstrip cement, plastic glue, etc.) The RTV helps keep the screws from backing out. After the RTV sets, I slip a bit of heat shrink (1-1/2" long) over the plug and connector and over the cable grip clamp area. (Unfortunately the RS selection does not have a this large size. I am not sure where to find it.) This _really_ keeps the screws from backing out. It also provides additional protection to the shell. (They can crack and split as they get abused in various ways.)

I do not use a "coil" cord on the vest end. I have used them and replaced them. They tend to be a light gauge wire for flexibility and I want as much voltage and heat in the vest as I can get, and not in the wire. (Bigger is better here.) Also they can unplug, and drag against the muffler. This is not good. It makes a mess of the headers/mufflers. It melts the insulation off the coil wires. =8-0

I use that same speaker wire for the vest. Sitting on the bike, I set the vest end length so that it will not, or just barely hits the muffler when it is unplugged. (The heat shrink is real good here. It resists muffler melting pretty well.) I then make the intermediate cord that plugs into the accessory socket pretty short. This keeps the _socket_ from dangling onto the headers or the muffler. This is worse than the vest end as it is energized. (Remember, no prongs sticking out!) ==8-0 I find that the vest end will not drag on the ground with my height.

BMW/Deere Accessory plug modifications:

I also work these over. I do not want any corrosion to prevent voltage from reaching the vest. I "Scotchbrite"/"Scrubby" four areas that are electrical connection mechanical joints. I clean up one of the three places where the outer shell goes through the circular brass plate. I do the one right next to one of the square blocks one of the wires connect to and on the side away from the screw. I also clean up the center area where the center connector is swaged to the strip that connects to the other square block. I then solder the shell through connection to the square block. You will need a soldering gun to put out enough heat get the solder to flow. I then solder the center pin to the strip and onto the connection block. Be careful with the amount of solder used. Check and see if it will fit in the side of the plug shell with the threaded inserts. There is not a lot of room in the outer shell and you don't want to be filing. :(

When I install the wires I do a few things different. First, there is not a lot of space in the shell. Again, I slip heat shrink over the cable. The two blocks are slightly different in "height" so one conductor should be trimmed about 1/16" shorter than the other. Strip about 1/8+" insulation off the end. Tin the end. Put the wire in the blocks. Tighten down the screws. Put the plastic shells over the connector body, tighten the clamping screw and make sure the screw heads are not pushing the shells apart. (More later on this.) If they are, tighten the wire clamping screws some more. I now do something unusual. I solder the wires into the blocks. If I ever have to get them apart it will be a bear, but I will not have any bad/high resistance connections. :):) Now, put body in the threaded insert shell, and mark where the clamp will come down on the cable. Remove the body, position the heat shrink, and shrink it where the clamp will contact it. This keeps the cable from splitting further, and protects the wire from being shorted if the clamp pushes through the insulation. (See a consistency here?) Put the body and shell together, install the cable clamp, put on the other shell and tighten everything down. I now put a some heat shrink over the whole shell. (1-1/2" long) (Again the RS selection is not big enough around.) Put the connector in the accessory socket and trim the heat shrink if necessary for a firm connection. The shell is fairly brittle. I had one split due to the screw head being too high. I also had a shell come apart due to the screw loosening. With the heat shrink, the screw will not come out and the shells cannot come apart, plus it is impact toughened.

I now have "stout/ruggedized" connectors, connections, and wire with minimum voltage drop. You will have connectors that will last a long time, will not loosen up, will not break where the wire enters them, will resist melting, and will not leave you cold at some critical time. :):)

Note, I do not work for Radio Shack. I use their parts and part numbers because they are ubiquitous in the United States

Brian Curry, (bmwbrian@voicenet.com) 1990 Blue K75RTs both coasts
Chester Springs, PA, USA
K-Whiner #21, BOOF #38, OSP #7, "VI,CE" "IWT"
BMWMOA#4578, BMWRA#12296, AMA#725653, USCA#078, PE-029523-E, N3IYL

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Last Update: Monday, December 15, 1997