INSTALLING AN ACCESSORY ELECTRICAL OUTLET
on BMW Airhead Motorcycles
© Copyright, 2012, R. Fleischer
accessoryoutlet.htm-27
There is nothing very
complicated about installing the standard accessory
outlet socket onto almost any airhead. The female
accessory socket and mating male plugs are available from many sources ...and various
styles of these sockets are available. However, there are some
hints and precautions you may not know about, that can save you some hassles,
and even money.
An accessory outlet should have, or you should incorporate,
a FUSE in the POSITIVE (+) lead which is usually red, and
this is the
lead that goes to the CENTER jack contact. The STOCK fuse size was 8
amperes, and should be wired directly to the battery + terminal, unless you have a
REALLY GOOD reason to wire it through the ignition switch. I
suggest wiring directly via a fuse to the battery, thereby
avoiding having to have the ignition switch ON. The accessory socket
(jack) is an excellent place to plug in your battery
charger (or heated clothing), and thereby avoid problems with alligator clips, sparks,
etc. You wouldn't want the key ON, during battery charging, so wiring it to the
switch is not a great idea (unless to the input side of that switch, for a
nearby mounting of the outlet). Use
appropriate gauge and insulation wire type, and put the fuseholder in a convenient place.
***SEE
later in this posting about the negative wire!!
Have the outlet located where you won't have excessive wire
lengths....or other problems such as long wires pulling on your
clothing;....when you plug in your heated clothing and mount and
dismount the bike. Some folks will have two or even three of
these accessory sockets, some have one direct to the battery and others through
the ignition switch.
For the RIDER who happens to have an appropriate fairing,
consider the rear of the fairing left pocket, if it has
one;....as MOST heated vests have the VEST connection on the left
side, AFAIK. If you put the jack in such a place, be SURE
nothing put into the compartment can cause a short circuit.
Shrink tubing or other good insulation is usually a good
idea. Black
electrical tape or worse yet, duct tape....are not a good idea...they tend to unravel over a long time period, besides often
making a sticky mess after some time.
If you have a fairing, and a passenger along that wants heated clothing,
probably at least two separate outlets is better, with the passenger outlet being in the stock area that BMW provided (at the
seat lock area on the left side ...obviously this does not apply to
those with rear seat locks such as a ST model). Some
folks install three of these jacks, and run all sorts of
electrical devices from them.
The stock position for many BMW airheads was at the left side
seat lock area and BMW had a thick sheet metal bracket just for
this outlet. See any BMW with one of these, they were standard on
many models (especially RT).
The part number for the socket has been changed now and then, for example it was
61-13-1-243-661, now is 61-13-1-379-719; and the folding weather protecting
cover for it was 61-12-1-243-662, which became 61-12-2-393-574. Better check
those numbers, may be wrong by now. Old style sockets used either no
cover, or a rubber cover, and some versions of them have a plastic
flexi cover, that will eventually break.....the better type, K
models, had a hard cover, spring loaded. Be very
careful you get the type you want, and that it is reasonably
weatherproof.
There are 90° PLUG assemblies on the aftermarket, so the
plug goes into the sockiet without sticking very far outward.
For models like the R65, the fuse box is on the right side of the
frame and could be modified for an extra socket.,,,,perhaps not so
convenient for clothing. That fuse box...on rear of the
box...might be a convenient place to mount a heated clothing
thermostat.
Be cautious. You do NOT want any wire, connecting
to the outlet from your clothing, becoming
disconnected....and flying into your rear wheel!
I suggest not fastening the socket to the handlebars, due to possible constant
wire movement problems, and perhaps safety problems. Could be
done properly, of course, and BMW included such on some models, like some of the
K bikes where BMW installed a jack on the bars trim piece.
BMW also usually installed two other jacks, near the ignition
coils, on such as the K-LT models.
One CAN make a bracket, or maybe purchase one, and mount a standard cigarette
lighter jack someplace similar. Most of these jacks have a somewhat flimsy outer
metal shell that acts as the 'nut' and must be installed securely and
electrically solidly correct for grounding. I do not like them for their poor
grounding, and that the center contact is fairly poor, compared to the type of
gripping contact (DIN plug, DIN jack) for the stock BMW plug and socket.
Some of these cigarette jack shells do have a grounding spade tab,
however....but mostly that ground tab is from the shell-nut; but those with the
tab from the inner piece are much better.
Whatever you do, do it neatly, fuse the positive lead, and install the wires and fuses such that they won't
short circuit or fray from
vibration. If the wires are substantial in size, you could
go as high as 30 amperes, which is about the limit for the jack
and plug. Don't willy-nilly go to large fuse sizes if you
have no REAL need. Don't try to have high current
capability if you wire this through the ignition switch, that
switch is not rated for much more than it carries already.
***ONE
special precaution:
When you attach an
accessory socket...or anything electrical really...to your
airhead (this can apply to many other bikes too)... you may or may not be contemplating the connection of
its grounding or negative wire to the ACTUAL battery negative
POST. I feel that it is BETTER, over-all, to NOT connect
this accessory jack...radio....or whatever....directly to the
battery negative post. While electrically it may be a TEENY bit better under SOME situations, a problem can
come up, so I am advising NO direct connections to the battery
negative post.
Here
is the reasoning:
It is STANDARD practice on a BMW airhead to electrically disconnect the battery,
when you need to do such as remove the outer timing chest cover; by removing the
battery heavy negative black wire from the transmission speedometer cable hollow
vent bolt. This thin hollow bolt is located at the right rear of the
transmission. That bolt has a triple function; it grounds the battery to
the engine, it vents the driveshaft and transmission, it secures the speedometer
cable. Thus, if you have something connected directly to the battery
negative terminal that is, in itself,
grounded, such as the shell of an electrical
outlet socket
(some shells or outer parts are grounded by the mounting)...then you are defeating
the purpose of disconnecting the large gauge battery wire at that hollow vent
bolt (or, other place someone may have connected it to, such as the frame or
transmission)....and can seriously damage your diode board, as one example, upon removing
the front cover.
By grounding your
accessory outlet to the FRAME
someplace, and NOT the
battery negative terminal, you avoid such problems.
With
SOME accessory sockets (yes, even some of the DIN German type),
the shell is insulated; with others the negative is part of a
metal shell, and if it is mounted in the plastic of the fairing,
there MAY be no problem. So, no matter what the situation, and
it varies, be sure that the negative connection is to the frame,
not the battery negative post, UNLESS you KNOW what you are
doing and WANT it that way!
When I post something to the Airheads E-mail LIST about
electrical work you may read that I said to remove all
wires at the battery NEGATIVE "POST"...this ASSURES no
ground paths, no matter WHAT someone did with
the wiring. It is a safety precaution for me to say it that way,
and in line with the above paragraph, now you know why.
I suggest you not add things to the battery negative post,
and instead find another grounding point for your accessory
outlet. Look for most anyplace on the bike that has a screw or bolt
to the frame, and/or maybe one or more brown wires connected at
that point. Along the backbone is at least
one such place.
HINT: It is convenient to cut a SMALL slice out of
the battery lug located at that speedometer cable point...so the vent screw only
needs slight loosening. Be sure your hollow bolt
has the washers on it, which will prevent spreading of the lug. The battery lug goes between the
washers.
revisions:
11/14/2008: incorporate all prior revisions, and update for clarity
05/02/2011: more darn clarifications, and some cleanup
05/06/2012: Clean up a bit more
© Copyright, 2012, R. Fleischer