Making the Bosch Metal Can Electronic Voltage Regulators Adjustable
©
boschelreg.htm-22
NOTE: I put this article on this website because a
FEW people asked for it. MOST would never attempt to modify
the electronic regulators, for one good reason: This
article cannot cover every variation; but, mostly, the reason is
that you can purchase an adjustable voltage regulator quite
reasonably from Stan Smith at
http://www.RockyPointCycle.com so why spend the
time?...unless you like to fiddle around.
NOTE!!
There are metal can regulators that have a Wehrle label on top, the one I have
seen is stamped with a model E 1051 B/14V. Made in Germany.
These regulators have a similar circuit to the Bosch regulator which is what the
following procedure is specifically for. This Wehrle metal can regulator
has the same sort of circuitry and adjustment control inside. It might
even have been made by Bosch. The exact same procedure is involved....and
the same hole drilling, etc.
This is a how-to article, the purpose of which is to make your Bosch ELECTRONIC metal can unit 'voltage adjustable'. NOTE that this is NOT for the similar but larger mechanical Bosch regulator...see BOSCH METAL CAN MECHANICAL VOLTAGE REGULATOR. That is a hyperlink to that article. Elsewhere's on this website will be found an article on increasing the voltage output of the Wehrle electronic regulator. Yep, another hyperlink.
The Bosch
Electronic Regulator: There are numerous ways to increase the
voltage, which is the usual desire, including adding a tiny
diode, but the method described below makes it fully adjustable.
Don't
attempt this if you can't work on small parts and use a
small soldering iron comfortably. You MAY not need the soldering
iron.
Parts needed:
1. One rubber grommet....no special size, from Radio
Shack or ? One with a 3/8" mounting
hole is fine, so is one of 1/4" or 5/16". The 3/8" or even
a 1/2" might be better if you are not good at making measurements on where
to drill....read this procedure through. You don't HAVE TO have this part,
but you probably will want it. You will also want a common black plastic
body plug that fits the center hole...or, you could use tape. Plug is
nicer. RTV cement is nice to seal the plug so it stays in place.
2. A few Q-tips and some acetone or similar strong
solvent.
3. Small jewelers screwdriver.
4. Drills/reamers...whatever.. (optional).
5. 100 ohm potentiometer...in case you ruin the
existing one; then you'll need a small soldering iron
and bit of 60/40 electronics solder. The
potentiometer is a small variable resistor used in electronics, and would need
to mechanically and electrically fit the existing regulator, many common types
fit just fine, some with very minor work. If you are careful, you will NOT
need this part.
The electronic Bosch voltage regulator consists of a number of
transistors,
diodes, resistors & capacitors, the purpose of which are not
important to this article.
Modification:
1. Remove the regulator from the bike. There are two
allen head screws, and a plug to disconnect.
You don't have to remove the battery connection.
2. Remove the tape from the regulator that keeps the
top can from coming off.
3. Gently wiggle the top can off the base.
4. Inside you will find a printed circuit board with all
the components mounted upside down...that is,
underneath the board. On the end of the board
OPPOSITE the plug/socket end, you will find a small
electronic device called a pot (short for
potentiometer). This is the factory adjustment
control. Every one I have seen is always sealed with a drop of a hard to
remove white paint.
5. Try to remove or at least release the paint with repeated soakings of a
q-tip in something like acetone, or paint remover
(?). This can take some
time. If you are successful, the pot will be usable as
is, and can be adjustable. If you are not successful,
you can try VERY GENTLY prying a tiny bit at the
paint, to free up the lower adjustment fingers metal
ring. Do NOT pry much. If you ruin the pot, it will
have to be replaced, with any common 100 ohm
pot...that fits, or can be made to fit.
NOTE!!: I have found it best to CAREFULLY unsolder the three
legs of the
pot and remove it, and soak it in acetone for a short
while....which ALSO gives me SAFE access to
ENLARGE the very tiny hole for the adjustment, that
is stock, on the board. If you are VERY careful you
could leave the pot and drill out that hole by
hand...don't ruin the pot. **You don't HAVE to drill
the tiny hole larger, but you will need a VERY TINY jewelers screwdriver for the adjustment, if you
do not.
6. Assuming the pot is operational, or the replacement
is installed, and the circuit board existing hole is enlarged for access by a
proper sized jewelers screwdriver, you have an
optional step now: That is to drill the thin metal
cover in the appropriate place, and install a rubber
grommet. The purpose of the rubber grommet is to
keep you from shorting the pot metal to the regulator
cover metal when adjusting the voltage regulator. You don't have to
have the hole and grommet, you can set the regulator without the cover on.
Elsewhere's on the website is information on generically measuring the set point
of regulators. testingvoltageregulators.htm
At the end of THIS article you are reading is a bit of information on adjusting, via a simple method. I suggest you disregard that ABOVE hyperlinked article and drill the hole! I also suggest you don't try to do the bench test information at the end of the article, unless you are the nerdy technical type with an adjustable supply, ETC.
You WILL find
the hole convenient!... for future adjustments...if you change the battery to a
type needing a different voltage, ETC.! NOTE that if you use the
grommet, it is nice to seal it's hole with something. I use a common black
plastic auto-body plug, that fits into the center hole, and I use a wee bit of
silicon rubber...that stuff in a squeeze tube. Easy to remove and readjust
whenever you might like to.
7. Be sure all is assembled correctly if you removed the pot. Re-check your
work. Install the cover, be sure the
jewelers screwdriver will fit the tiny pot slot and
operate the pot. If you are worried about the pot
being OK, you could use an ohmmeter on the pot
and prove that the pot is about 100 ohms between
the ends, and that the wiper, with respect to either
end, works properly.
8. Reinstall the cover tape and install the regulator on your bike and plug it
in.
9. Adjustment of the regulator is, of course, by the jewelers
screwdriver, making SURE the metal of the jewelers
screwdriver canNOT contact the metal can. The
screwdriver MUST be the right size, or you will ruin
the pot. Be gentle in any downward pressure.
10. The voltage setting depends on your usage of the
bike, and the type of battery, and the temperature
of the regulator when making the adjustment. The
regulator is temperature compensated and DESIGNED to INcrease its voltage as the
temperature of THE REGULATOR goes down.
Some guidelines:
Assuming a 70°F day, engine started and regulator
adjusted within a FEW minutes...so the regulator has
NOT warmed up from engine heat, and the battery is
fully charged to begin with...with only the starting-up
drain, and the bike at perhaps 3500-4000 rpm for a
minute or so....or, the voltage is no longer rising from
recharging the battery. For the common flooded
batteries, a good compromise between water usage and charging is 14.1 optimum, range 13.7-14.3
For other temperatures at the regulator can when you adjust it:
For 47°F 13.8-14.4
For 93°F 13.6-14.2
For 117°F 13.5-14.1
Those doing commuting, stop and go and city driving
probably should use the higher end of the above ranges, or
even 0.2 volt more.
NOTE: It appears that the sealed Panasonic/WestCo batteries may like a slightly higher voltage. I am presently suggesting 14.5 volts at 70°F. Stop and go commuters could try as high as 14.9 at 70°F.
NOTE!!! All voltage readings are taken AT the BATTERY terminals themselves!!, and NOT your fairing voltmeter!!!
For those having an adjustable power source, and
wanting a 'bench' test. An APPROXimate adjustment method
follows. Keep in mind that this is NOT a test ON the bike, but with the
regulator on your workbench....seems self-evident, but have had some confused
readers!
I use an old headlight lamp as a load, but almost any
lamp or 5 to 20 ohm resistor will work (power resistor of
10 watt rating is OK for short term testing). Frankly,
it is FAR easier to use the lamp!
Connect one
side of the lamp to the terminal marked DF, and the
other side of the lamp to the power source negative. Connect the D+ terminal to the power source positive.
Connect the power negative to the D- terminal. Monitor
the voltage of the power source (that is, from D+ to D-).
Raise the voltage VERY slowly. As the voltage rises, the lamp
will start lighting up. Continue to raise the voltage very slowly. The
lamp will suddenly go OUT. Note the voltage
JUST BEFORE, as closely before, the lamp goes out, as you repeatedly retry this
testing. A retry means to lower the voltage and start raising it
again, slowly. Adjust the pot to where you want the voltage, install the regulator into the motorcycle as
noted, and making final adjustments if you have to.
Revisions:
01/16/2010: all prior rev. included. Minor cleanup