12V Alternator Conversion Guide
Kansas
Select Products Alternator Conversion Parts
With proper
consideration to each of only some few matters the 6-volt generator to 12-volt
alternator conversion is easily and well done by any sincere shade-tree
mechanic. This guide provides information on alternators, voltage regulators,
ignition coils, belts and pulleys, mounting brackets, dash gauges and other
accessories and devices.
The
Delco 10SI alternator is the top choice for a 12-volt alternator conversion. An
alternator conversion is attractive because it offers more power, less
maintenance including the option of using low-maintenance sealed batteries, and
increased reliability. The SI series alternator made the 12V alternator
conversion more reliable and popular because it introduced an integral,
solid-state voltage regulator which eliminated the troublesome OEM external
electromechanical voltage regulator. The 10SI is the choice of the SI series
because the 10SI starts charging at a lower engine RPM and because it produces
more amps in the lower RPM range than the other SI alternators. You can see the
lower RPM performance on this 10SI
curve. This low RPM performance remains important in industrial and
agricultural power units and continues to be relevant to the early model, lower
RPM engines. The 10SI is the top choice because of its price, availability,
performance, reliability and suitability. Kansas Select Products has 6-volt and
8-volt 10SI alternators that also provide these benefits to the guy who doesn't
need 12-volts for any particular reason. Going with a 6-volt 10SI is affordable
and nice because there is no fuss with other electrical modifications,
replacements or changes except for perhaps reversing the battery polarity. The
6-volt 10SI puts out 32-amps. 10SI physical dimensions.
Perhaps
there are early model fire trucks, ambulances or other special equipment
vehicles which require more than the 63-amps produced by a 10SI but generally
the 10SI has enough capacity for vehicles up to and including later model, air
conditioned family sedans. You can use your ammeter to measure amps by
switching on each device in turn while the engine is not running or turn
everything on to read the total amp draw. You need some margin of excess
capacity and 42-amp total draw leaves a very comfortable 50% margin of 21-amps
for the 63-amp alternator. You can lower the amps required by the lights and
devices now on your 6-volt vehicle.
Replacing
6V devices with 12V devices will cut the amp draw by half meaning you will have
more alternator capacity available for additional devices or to provide the
margin of excess capacity. When converting to 12-volt from 6-volt one can
typically and easily replace light bulbs, flashers, wiper and blower motors and
other voltage sensitive devices with 12-volt equivalents and the replacements
use 1/2 of amps.
The
12AWG wire used with many generators is just large enough for the higher
maximum amp alternator; just barely and only if the wiring is not exposed to
very high operating temperatures and the alternator is not heavily loaded. Of
course your system may never draw, and that wire may never have to conduct, the
full 63-amps so many run with the 12AWG and accept the risk the wire and
alternator might prematurely fail. It would be unwise to not replace a 14AWG or
smaller wire. Replace with at least a 10AWG wire. Here is a wire
gauge selection table. Under-sized wire unnecessarily loads an alternator,
or any electrical device. If a wire feeding a motor is too small the wire will
be over-loaded, the motor will be volt-starved and you can expect the wire and
the motor to prematurely fail. It works kind of the same way except backwards
for an alternator which is additionally loaded and harshly over-worked by a too
small wire. I'm talking about all the wire between the alternator charging post
and the battery which usually means a termination on the starter solenoid
because there's a cable from the battery to the solenoid and that cable is big
enough.
Voltage regulator & wiring the alternator:
The
internally regulated 10SI 12-volt alternator conversion does not need and
cannot use an external voltage regulator (VR) or cut-out relay so you must
disable, jump around, modify or remove what you got. Up to you if you want to
remove what you got and rewire the harness, jump around what you got and use it
as nothing more than a terminal block, or get inside what you got and make
jumps and modifications so outward appearances remain the same. Here's what you
need to know: one, the large wire on the generator (only wire on some
generators) is the charging wire and it runs to the VR or a cut-out relay. A
vehicle will not have both a VR and a cut-out relay. The other side of the
cut-out relay or another terminal on the VR will run over to connect to one
side of the ignition switch (other side of switch goes to the ignition coil),
one side of the ammeter (other side of ammeter goes to the battery via the
solenoid), and one side of the light switch (other side of switch goes to the
lights). The wire from the VR or cut-out relay typically comes together with
the wires off the ignition switch, ammeter, and light switch on a terminal
block. So one, the charging wire that runs from the generator has to be tied to
the other side of the cut-out relay or that other terminal on the VR; so much
for the charging wire. What remains is that the remaining wire coming off the
10SI alternator connects to the other side (ignition coil side) of the ignition
switch which can happen by connecting to the other side of the terminal block
or even the hot (ignition switch) side of the ignition coil. Any remaining
wires on the generator or VR are not used and should be removed or dead-headed.
So that gets the engine running and the battery charging but now the OEM
2-position ignition switch won't shut off the engine. A multi-position
Off/Start/Acc/Run ignition switch will shut off the engine because you connect
the alternator to the ACC terminal. So now you need a trick to shut off the
engine.
The
trick is to put a one-way block in the wire between the alternator and the
ignition coil side of the ignition switch. I recommend a diode but a light or
some other resistor will do well enough if the vehicle is operated often. The
diode block prevents any battery discharge while a resistor dramatically slows
down any battery discharge. That diode block or resistor allows you to retain
and use the OEM 2-position ignition switch. The diode block is not required
when you have a later-model, multi-position ignition switch.
There
are two diagrams that may help. Here is the
fundamental charging and ignition circuit. Cut through the clutter of
unrelated wires, doodads and gizmos and your vehicle is pretty much the exact
same thing. Here is the straight
up 10SI connection diagram.
Reversing the polarity:
An
alternator most always requires a negative ground so you may have to do a few
things. You must re-install the battery with the negative post grounded. You
must change the wires from one post of the ammeter to the other and vice verse
or the ammeter will read backwards; e.g., discharge while charging, if you
don't. Ford loop-type ammeters can be reversed by pulling the wire out one side
of the loop and threading it back through from the opposite side. The test is
to see that the ammeter shows a discharge while cranking the engine with the
ignition switch turned on. On a running engine you turn on the lights and the
needle should move in the discharge direction. It's a good thing to reverse the
primary (smaller, low voltage) wires on the ignition coil by moving all the
wires on the coil's positive (+) terminal to the coil's negative (-) terminal
and vice verse. The ignition coil wire swap is not that big a deal so don't
fret if you can't get it done. You may continue to use a stock 6-volt ignition
coil if you install a voltage drop resistance. Here is the ignition
coil voltage drop wiring diagram.
Most
any usual automotive starter and electrical accessory can operate as either
negative or positive ground with no change in performance or direction. A 6V
starter will last a good long time especially if you let it cool-down
one-minute for every 15-seconds of cranking. A 6-volt starter solenoid may also
last a long time but replace it with a 12-volt when the time comes.
Six-volt
accessories and devices like gas and panel gauges and radios need special
attention. Those devices are not simply on/off because they draw a varying
amount of amps during normal operation. Compare to an ignition coil or wiper
motor that is either on or off and the amps do not vary during operation. You
will get fine results with a simple, but properly sized, resistor voltage drop
(constant resistance matched to a constant demand) on an ignition coil or wiper
motor (note that a single, same-size resistor does not fit all and any motors
or other device) but you will not typically get fine results using a simple
resistor voltage drop. On those other devices the amps vary. A gas gauge has a
difference resistance and different amps at empty then it does at full. A radio
uses less power at low volume then it does at full volume. You need to use a
constant voltage/varying demand voltage drop and that will be some type of
electronic device. Kansas Select Products offers a range of voltage drops to
satisfy most any requirement.
One-wire 10SI:
The
Delco SI 1-wire has its uses. It is used on agricultural irrigation engines and
in marine applications. It has been used on automobiles and other vehicles
because it's easy to install and does not require a pigtail connector. That's
not to say the 3-wire is difficult to install. The pigtail connector is
available and will give access to the superior regulation provided by the
alternator's solid-state voltage regulator. The one-wire cannot
"sense" and adjust its output to provide a constant vehicle operating
voltage depending on the load demand. The one-wire is a good fit for an
irrigation engine that runs at one speed, has a constant load, and constant
demand. An external relay must be used with a 1-wire to operate an idiot light
in the dash. One-wire alternators also have "turn-on" issues because
it must self-excite using residual magnetism in the iron parts of the
alternator. If there is magnetism in the parts and the alternator is run up
fast enough then enough power is produced to excite the alternator and it will
ramp up the output. If it sits so long that no magnetism remains then that does
not happen. The one-wire sitting idle will drain a battery over time. The
1-wire is not the better choice for engines that may sit idle for long periods,
may be operated only at lower engine RPM's, use a dash light, engine RPM
routinely varies, or where blower motors, headlights and other load demands
come and go. My Ford tractor idles at less than 400-rpm and normally operates
just over 1500 so I would always have to be certain to rev up a self-excite,
1-wire alternator so it would begin to output regardless of how I will
otherwise operate the tractor. I don't mean to take anything away from the
one-wire alternator but the standard three-wire is a more sensible alternator
for most any application. One-wire alternators are also more expensive and not
as readily available.
The
3-wire will always turn-on at the lowest possible RPM because it is excited by
the battery voltage via the ignition switch to the alternator excite terminal
right from the get-go. The 63-amp 10SI won't put out amps until 1,000+RPM but
it is turned on and ready once the switch is on. The 3-wire with a diode in the
excite wire will give you the lowest RPM turn-on possible and eliminate any
battery-draining leakage current during long down times. The 3-wire hook-up is
straight forward with one wire going no farther than the alternator itself. The
10SI alternator wire harness with the DA-plug makes it a snap to wire up the
alternator. The harness also makes it simple to keep the dash light in the
circuit. No additional resistor is required when using the diode. The 63-amp
10SI begins charging at a lower RPM than any other size (amperage) 10SI, even
the lower amp 10SI's. Big plus when using the diode is that it allows you to
continue using an OEM on/off key-switch. You can use the standard 10SI pig tail
if you have an off/on/start/run ignition switch so you can isolate the
alternator from the battery by connecting the alternator to the accessory
terminal.
Belts, pulleys, and brackets:
Modern
belts do not fit older vehicles so the pulley that comes with a standard 10SI
will not match many early model vehicles and engines. Vintage autos likely have
at least a 1/2" wide crank and water pump pulleys and agricultural or
industrial engines may have 5/8" or larger pulleys. To get the 12-volt
conversion right means you need to measure the pulley on the crank or water
pump and install the proper wide-belt pulley on the alternator. My pulleys are
small diameter so to get that alternator up to speed at lower engine RPM. Don't
measure the existing v-belt because no telling how that type and size belt came
to be on your engine; measure the pulley. There is a lot to v-belts and running
the improper belt can be no end to problems and premature failure. You also pay
for a belt/pulley mismatch in horsepower (mileage). You can find most vehicles'
belt size on this parts
interface look-up. Note: after completing the type, make, model, year
selection, keep clicking on the part number until you get a pop-up Product
Detail which shows Top Width (In.).
I
list brackets for most applications but if you have something else again then
let me know what and why and see if I can fix you up. Compare fit and function
to your project and you will see this 12-volt alternator conversion thing isn't
going to be such a big deal. My products are heavy-duty, high-quality, and
nearly all of it is made in the USA. You need a good, hard mount or the belt
will slip under load so you won't get a good charge and you will wear and throw
belts.
Clocking the alternator:
Keep
the regulator connecter pigtail wire harness away from the manifold and in a
location where you can get at it. The Delco 10SI alternator can be
"clocked" to bring the wire harness pig tail receptacle around to
whatever location so that engine parts do not interfere with the alternator
wire harness. Two things to keep in mind when clocking the 10SI: one, the
laminated ring between the front and back case halves goes with the back case
and not with the front (drive-end) case. Two, you have only a long 1/16"
difference between the brushes slipping out of the brush holders and not
slipping out of the brush holders and you do not want the brushes to slip out
of the brush holders. With that in mind, remove the 4 long case bolts. Ease the
case apart a total of 17/32" (you begin with 7/32" space so the total
movement will be another 5/16") and then rotate the drive-end case. You'll
know the brushes slipped out of the brush-holders when you hear a rapid
click-click or when the case won't go back together with only gentle to
moderate pressure. If the brushes slip out then pull the case completely apart
and reset the brushes as follows.
There
are holes in the brush-holder for a drill bit or piece of wire that can retain
the brushes and springs while you reassemble the case. The holder must be long
enough to stick out the hole in the back of the alternator case. Other than
wanting room for more fingers, it's no big deal; 2-minutes on a good day,
20-minutes on a bad day. Just remember, easy does it and if you have to push
anything with more than gentle to moderate pressure then it's not right and you
need to back up to see what you got wrong; that includes springs, brushes,
wire, and case halves.
Note:
the laminated ring between the case halves goes with the back case half and not
with the front pulley end case half.
Dash gauges and instruments:
You
have dash gauges or you have an instrument cluster. Older temperature and
pressure gauges will not be electrical gauges. Some electrical dash gauges run
right off 6-volts (very early models and then mostly GM) while other dash
gauges and nearly all instrument clusters use 5-volts. The 5-volts is done by
an electro-mechanical instrument voltage regulator (IVR) fed hot with 6-volts.
The IVR is often a 1" X 2" sardine-can-with-wires kind of thing that
is going to be separate from the dash gauge but will be attached to the back of
an instrument cluster. It may be built in to some instrument clusters
(AMC/Jeep). A Jeep cluster might use an IVR that is a big wire/tube-looking
thing between the 6V gauge and the 5V gauge both used in the same cluster. An
IVR can be retained but the mechanical contacts and heater are a source of
problems and change. Might be better to remove and wire around that IVR and use
a solid-state 5-volt voltage regulator to update those gauges. Use a 12-volt to
6-volt voltage reducer to update gauges not associated with an IVR or to feed
an IVR hot. Use a 12V to 6-volt regulator/reducer made to replace the IVR if
you would like to remove that electro-mechanical IVR to upgrade your
instrumentation. The voltage reducers and regulators are available from Kansas
Select Products.
Voltage
reducing resistors are not the way to go with dash gauges and instrument
clusters. Use a resistor and the needles will move but the gauges won't be
telling you what you want to know. Put a little thought and effort into the
voltage, use the correct parts and those old gauges can work very well and give
you better information than they were able to provide the day your vehicle came
off the production line.
I
hope you found some info you can use in my guide. I'm sure the guide can be
improved so I would be happy to hear from anyone with better, different, or
more information. Kansas Select Products (on eBay and also on the web) items
are quality and have good value so please take a look at my 12-volt conversion
parts. Please send pictures of your ride using my parts! You can find links to
more and tech specific information if you click "me" in the menu on
the left side of this eBay page. Happy motoring, everyone.
DISCLAIMER:
due to the many different types of vehicles it is impossible to provide
instructions for each possible application. The information provided herein is
offered to provide general instructions for a qualified automotive electrician.
The purchaser must make the determination of the suitability of any of these
products for any specific application. The information presented is my best
effort but you take it 'as is' and with no warranty.
Click
for Kansas Select Products Alternator Conversion Parts