Minuteman 957740 User manual

www.minutemanintl.com 1 31218C

36 VOLT AUTOMATIC
BATTERY CHARGER
PART NO. 957740
Specifications
AC Input: 108-128 Volts AC, 15 Amp, 60 Hertz, single-phase
DC Output: 36 Volts DC, 36 Amp
Connections: 6- or 9-ft. AC input cord with NEMA 5-15 grounded plug
8½- or 10-ft. DC output cord with polarized connector
PLEASE SAVE THESE IMPORTANT SAFETY AND OPERATING INSTRUCTIONS
For correct operation of the equipment, it is important to read and be familiar
with this entire manual before installing and operating the charger.
DO NOT DISCARD THIS MANUAL AFTER READING.
LOOK FOR THIS SYMBOL TO POINT OUT SAFETY PRECAUTIONS. IT MEANS:
BECOME ALERT—YOUR SAFETY IS INVOLVED. IF YOU DO NOT FOLLOW THESE
SAFETY INSTRUCTIONS, INJURY OR PROPERTY DAMAGE CAN OCCUR.
Features
•Patented electronic timer monitors battery state of charge while charging and automatically turns charger off as battery
reaches full charge
•Compensates automatically for AC input line voltage variation by high reliability ferroresonant transformer design. Supply
voltage variation + 10% from nominal, + 1% maximum battery charger voltage variation, decreasing to + ½% at finish rate
with constant electrolyte temperature. No taps or rate controls to set.
•Automatic decrease of charge rate for superior battery life through good equalization of cells and low water use rate.
•Silicon diodes with inherent surge protection operated at a conservation percentage of their rating.
•Convection-cooled design for maximum reliability and minimum maintenance.
INTRODUCTION
This automatic battery charger is designed to
recharge deep-cycle, lead-acid batteries. A
ferroresonant transformer is used to provide a highly
reliable, line compensating unit with a minimum of
moving parts, designed for long, trouble-free service.
A patented electronic timer turns the charger on and
off automatically. This electronic timer determines
full charge of the batteries by measuring the rate at
which the battery voltage increases during charge.
When the voltage stops rising, the battery is full
charged and the charger turns off.
INITIAL INSTALLATION
The AC line to which the charger is to be connected
must be capable of supply 15 amperes to this
charger.
CAUTION: USE ONLY ON CIRCUITS
PROVIDED WITH A MAXIMUM OF 20 AMP
(15 AMP IN CANADA) BRANCH CIRCUIT
PROTECTION IN ACCORDANCE WITH THE
NATIONAL ELECTRICAL CODE ANSI/NFPA 70
AND ALL LOCAL CODES AND ORDINANCES.
IMPROPER CIRCUIT PROTECTION MAY RESULT
IN A FIRE.


www.minutemanintl.com 2 31218C
The use of an extension cord with the charger
should be avoided. The use of an improper
extension cord could result in a risk of fire or electric
shock. If an extension cord must be used, use a
three-conductor, No. 14 AWG cord with ground,
properly wired, in good electrical condition and keep
it as short as possible. Make sure that the pins on
the plug of the extension cord are the same number,
size, and shape as that of the plug on the battery
charger. Locate all cords so that they will not be
stepped on, tripped over, or otherwise subjected to
damage or stress.
Do not operate this charge if it has received a sharp
blow, was dropped, or otherwise damaged in any
manner; refer to a qualified service agent.
Provide adequate ventilation for the batteries and
charger. The convection-cooled design requires an
unobstructed flow of cooling air for proper operation.
Keep all charger ventilation openings at least two
inches (2") (5cm) away from walls or other objects.
Do not allow clothing, blankets, or other material to
cover the charger.
WARNING: CHARGERS CAN IGNITE
FLAMMABLE MATERIALS AND VAPORS. DO
NOT USE NEAR FUELS, GRAIN DUST,
SOLVENTS, OR OTHER FLAMMABLES.
WARNING: TO REDUCE THE RISK OF AN
ELECTRIC SHOCK, KEEP CHARGER DRY. DO
NOT EXPOSE IT TO RAIN, POWER WASH
DETERGENTS, OR SPRAY. FOR STORAGE,
KEEP CHARGER IN A BUILDING.
ATTENTION! Ne pas exposer a la pluie.
GROUNDING INSTRUCTIONS
This battery charger must be grounded to reduce the
risk of electric shock. This charger is equipped with
an electric cord having an equipment-grounding
conductor and a grounding type plug. This plug
must be connected to an appropriate receptacle that
is properly installed and grounded in accordance
with the National Electrical Code and all local codes
and ordinances.
WARNING: IMPROPER CONNECTION OF
THE EQUIPMENT-GROUNDING CONDUCTOR
CAN RESULT IN A RISK OF ELECTRIC SHOCK.
The conductor with insulation having an outer
surface that is green, with or without yellow stripe(s),
is the equipment-grounding conductor. If repair or
replacement of the electric cord or plug is necessary,
do not connect the equipment-grounding connector
to a live terminal. Refer to a qualified service agent.
Battery chargers equipped with a grounding plug, as
illustrated in Figure A below, are for use on a
nominal 120-volt circuit. A temporary adapter, as
illustrated in Figures B and C, may be used to
connect this plug to a two-pole receptacle as shown
in Figure C if a properly grounded outlet is not
available. The temporary adapter should be used
only until a properly grounded outlet can be installed
by a qualified electrician. The green-colored rigid
ear or lug extending from the adapter must be
connected to a permanent ground such as a
properly grounded outlet box. Make sure that the
charger is connected to a receptacle having the
same configuration as the plug.
GROUNDING METHODS
NOTE: The use of the adapter shown in Figures B
and C is not permitted in Canada.
If a grounding type plug receptacle is not available,
do not use this charger until the proper outlet is
installed by a qualified electrician.
NORMAL OPERATION
The instructions printed on the charger are for
daily reference.
Output Polarity: WHITE, RED "+" POS.
BLACK "-" NEG.
CAUTION: USE CHARGER ONLY FOR
CHARGING 36-VOLT, 18-CELL SERIES
CONNECTED WET LEAD-ACID SYSTEM WITH A
CAPACITY OF 240 TO 370 AMPERE-HOURS (20
HR. RATE). OTHER TYPES OF BATTERIES MAY
BURST, CAUSING PERSONAL INJURY AND
DAMAGE.
ATTENTION! Utiliser pour charger
uniquement les accumulateurs au plomb à
electrolyte liquide. D'autres types d'accumu-
lateurs pourraient éclater et causer des
blessures ou domages.
DANGER: RISK OF ELECTRIC SHOCK! DO
NOT TOUCH UNINSULATED PORTIONS OF THE
OUTPUT CONNECTOR OR UNINSULATED
BATTERY TERMINALS.
DANGER: Risque de chocks électriques. Ne
pas toucher les parties non isolées du
connecteur de sorti ou les bornes non isolées de
l'accumulateur.

www.minutemanintl.com 3 31218C
1. With the charger DC output cord disconnected
from the batteries, connect the input plug to a
properly grounded 120 volt, 60 Hertz outlet with
the same number and size pins as the plug.
WARNING: TO REDUCE THE RISK OF AN
ELECTRIC SHOCK, CONNECT ONLY TO A
PROPERLY GROUNDED SINGLE-PHASE (3-
WIRE) OUTLET. REFER TO GROUNDING
INSTRUCTIONS.
2. Connect the DC output plug to the battery
receptacle by grasping the plug body or handle
and pushing the plug straight into the receptacle.
The charger will turn on with an audible "click"
after a short delay if all circuits and a battery
voltage test good. The transformer will "hum"
and ammeter indicate initial charge rate.
WARNING: DO NOT DISCONNECT THE DC
OUTPUT CORD FROM THE BATTERY
RECEPTACLE WHEN THE CHARGER IS ON.
THE RESULTING ARCING AND BURNING WILL
DAMAGE THE CONTACTS AND COULD CAUSE
THE BATTERIES TO EXPLODE. DISCONNECT
THE AC POWER SUPPLY CORD TO TURN THE
CHARGER "OFF" BEFORE DISCONNECTING
THE OUTPUT PLUG.
3. Monitor the ammeter for the initial charge rate.
The initial charge rate will vary from 32 to 40
amperes, depending upon the condition of the
batteries and how much the batteries have been
discharged. Slight variations in the initial charge
rate may also result from AC input line voltages
which are higher or lower than nominal. Higher
line voltages increase the initial charge rate
while lower line voltages reduce the charge rate.
If the batteries are heavily discharged and the
AC input line voltage is higher than nominal, the
initial charge rate may exceed 40 amperes.
Under normal conditions, the charger rate will
taper to less than 40 amperes within 90 minutes.
If the ammeter still reads more than 40 amperes
after 90 minutes, turn the charger off by
disconnecting the power supply cord from its
outlet.
CAUTION: TO PREVENT BATTERY
DAMAGE, CHARGER OVERHEATING, AND
TRANSFORMER BURNOUT, DO NOT ALLOW
THE CHARGER TO OPERATE FOR MORE THAN
90 MINUTES WITH THE AMMETER READING IN
EXCESS OF 40 AMPS. THIS IS MISUSE AND
WILL CAUSE OVERHEATING AND TRANS-
FORMER WILL BURN OUT.
4. The charge rate will decrease to 6 to 10
amperes for the last few hours of charge if all
battery cells test good.
During charge, the battery voltage increases
gradually causing the charge rate to decrease.
Good battery cells should each rise to
approximately 2.5 volts DC causing the charge
rate to reduce to less than 10 amps. Each cell
accepts charge differently; normal charging with
the ammeter reading in the 6 to 10 amps area
for the last few hours of charge is important to
achieve equalization of all battery cells every
time the batteries are charged.
As batteries age, individual cells weaken
resulting in lower than normal finish charge
voltage. As the finish charge voltage decreases,
the finish charge rate increases and no longer
reduces into the 5 to 10 amps range on the
ammeter. The electronic timer still determines
when the batteries have reached their maximum
state of charge and turns the charger off. Even
though they are properly charged, older
batteries will gradually lose capacity, and should
be replaced when they will no longer perform as
required.
The charger turns off automatically when the
batteries reach full charge. The necessary
charge time is affected by numerous factors.
The major factors affecting the required charge
time are better amp-hour capacity, depth of
discharge, battery temperature, and if the
battery is new or broken in. The required charge
time varies with battery size and depth of
discharge. Allow sufficient time, as listed in the
following charge, for normal charging.
Battery Capacity Normal Charge Time
(Amp-hours, 20 hr. rate) (Hours)
240 9-12
305 12-14
370 14-16
The normal charge times listed are for batteries
which have been discharged to 80% of their
rated capacity. As much as 4 ADDITIONAL
HOURS may be required to properly charge
batteries under the following conditions:
a. Heavily discharged batteries (more than
80% discharged).
b. Charging new batteries (batteries with less
than 50 discharge/charge cycles).
c. Charging cold batteries (ambient temper-
atures below 65°F). When charging new or
cold batteries, a higher than normal finishing
charge voltage can be expected. This
results in a low finish charge rate (2-5
amps), and additional time is required to
achieve equalization of all battery cells.
Refer to a qualified service agent if the

www.minutemanintl.com 4 31218C
charger does not turn off within the specified
time.
As batteries age, the charge rate may no longer
decrease to the 6 to 10 amp finish rate. This is
normal; as battery cells wear out, they weaken
resulting in a lower than normal finish voltage.
However, the charger will still determine when
the battery is as charged as it can be and then
turn off. Even though they are properly charged,
older batteries will gradually lose capacity, and
should be replaced when they will no longer
perform as required.
WARNING: DO NOT LEAVE THE CHARGER
OUTPUT CONNECTOR CONNECTED WHILE
UNATTENDED FOR TWO (2) OR MORE DAYS IN
A ROW. SEVERE OVERCHARGING AND
POSSIBLE DAMAGE TO THE BATTERIES WILL
RESULT IF THE CHARGER ELECTRONIC TIMER
KIT SHOULD FAIL AND NOT TURN OFF, OR
TURN BACK ON.
5. After the charger has been turned off,
disconnect the input plug from the receptacle by
grasping the plug body and pulling the plug
straight out of the receptacle.
WARNING: TO AVOID DAMAGE TO THE
INPUT PLUG AND CORD, DO NOT PULL ON THE
CORD.
BATTERY STORAGE MAINTENANCE
When the machine is not in use, charge the batteries
once a week; disconnect the plug at the end of the
charge.
PROPER CARE OF DEEP-CYCLE MOTIVE
POWER BATTERIES
Motive power batteries are subjected to severe
deep-cycle duty on a daily basis. Although these
batteries are designed to withstand such duty, the
following precautions must be observed to obtain
good performance and maximum cycle life.
CAUTION: ALWAYS WEAR PROTECTIVE
CLOTHING AND EYE SHIELDS WHEN WORKING
WITH BATTERIES. BATTERIES CONTAIN ACIDS
WHICH CAN CAUSE BODILY HARM. DO NOT
PUT WRENCHES OR OTHER METAL OBJECTS
ACROSS THE BATTERY TERMINAL OR
BATTERY TOP. ARCING OR EXPLOSION OF
THE BATTERY CAN RESULT.
1. When installing new batteries, be sure the
polarity of each battery and overall battery pack
is correct. Due to the electrical characteristics of
this charger, it is possible to hook up the
batteries improperly and not blow the fuse when
charging. Battery and/or charger damage can
result.
2. New batteries should be given a full charge
before their first use because it is difficult to
know how long the batteries have been stored.
3. Limit the use of new batteries for the first 20
cycles. New batteries and older batteries that
have been in storage are not capable of their
rated output until they have been discharged
and charged a number of times.
4. Do not excessively discharge the batteries.
Excessive discharge can cause polarity reversal
of individual cells resulting in complete failure
shortly thereafter. Heavily discharging (over
60%) new batteries before they have been
broken in (approximately 20 cycles) can cause
permanent cell damage, resulting in reduced
energy capacity and shortened life.
5. Maintain the proper electrolyte by adding water
when necessary. Distilled or deionized water is
free of contaminants and preferred for this use.
Never allow the electrolyte level to fall below the
tope of the battery plates. Electrolyte levels
lower during discharge and rise during charge.
Therefore, to prevent the overflow of electrolyte
when charging, it is mandatory that water be
added to cells AFTER they have been fully
charged; do not overfill. Old batteries require
more frequent additions of water than do new
batteries.
6. Hard crystalline sulfates form when batteries in
storage are not maintained in a charge active
state. Internal self-discharge can bring about
the start of this condition in as little as three days
in warm temperatures. Batteries allowed to sit
unmaintained in storage will self-discharge,
sulfate to various degrees, and lose capacity.
Repeated charging without using the batteries
between charges may recover some of the lost
power, range, and life, but some permanent loss
should be expected.
7. When the temperature falls below 65°F, the
batteries should be placed on charge as soon
after use as possible. Cold batteries require
more time to fully recharge.
8. The tops of the batteries and battery hold-downs
must be kept clean and dry at all times to
prevent excessive self-discharge and flow of
current between the battery posts and framer.
Electrolyte spilled on the batteries never dries or
evaporates and must be cleaned off.
9. All connections to batteries that are bolted must
be maintained clean and tight. Due to heating
and discharge rates, bolted connections loosen
over time. Re-tighten the connections twice
yearly to the manufacturer's specified torque.

www.minutemanintl.com 5 31218C
10. Follow all operating instructions, cautions, and
warnings as specified in this manual, on the
charger, and in your equipment owner manual.
TROUBLESHOOTING GUIDE
To be able to troubleshoot safely and effectively,
it is important to read this guide completely
before beginning any tests.
CAUTION: DO NOT DISASSEMBLE THE
CHARGER. TAKE IT TO A QUALIFIED SERVICE
AGENT WHEN SERVICE OR REPAIR IS
REQUIRED. INCORRECT REASSEMBLY MAY
RESULT IN A RISK OF ELECTRIC SHOCK OR
FIRE. THE FOLLOWING PROCEDURES ARE
INTENDED ONLY TO DETERMINE IF A
MALFUNCTION MAY EXIST IN THE CHARGER.
DANGER: TO REDUCE THE RISK OF
ELECTRIC SHOCK, ALWAYS DISCONNECT
BOTH THE POWER SUPPLY CORD AND THE
OUTPUT CORD BEFORE ATTEMPTING ANY
MAINTENANCE OR CLEANING; TURNING THE
CHARGER OFF DOES NOT REDUCE THE RISK.
WARNING: DO NOT OPERATE THE
CHARGER IF IT IS MALFUNCTIONING.
PERSONAL INJURY OR PROPERTY DAMAGE
COULD RESULT.
To determine if a charger malfunction exists, identify
the problem from the following list and refer to the
appropriate section for detailed instructions.
1. CHARGER DOES NOT TURN ON
2. CHARGER FUSE BLOWS
3. THE AMMETER NEEDLE REMAINS AT MORE
THAN 40 AMPS FOR MORE THAN 90
MINUTES
4. CHARGER DOES NOT TURN OFF
5. THE BUILDING AC LINE CIRCUIT BREAKER
OR FUSE BLOWS
If the problem is other than listed above, refer to a
qualified service agent for additional troubleshooting
procedures.
1. CHARGER DOES NOT TURN ON
The AC plug must be disconnected and
reconnected to start the charger after turn off.
Test for a live outlet by connecting a light or
appliance to the same outlet.
2. CHARGER FUSE(S) BLOW
The charger fuse assembly consists of a U-
shaped wire visible through a transparent cover,
and is mounted on the front panel. Electrical
connections to the fuse wire are soldered to the
middle and each end. Each half of the fuse wire
serves as an individual fuse link which protects
the charger in the event one or both rectifier
diodes fail, or a reverse polarity connection is
made to the batteries.
Check the fuse assembly visually for an open or
blown fuse link. If both half links of the fuse
assembly blow as soon as the DC output plug is
connected to the battery connector, the polarity
of the batteries may be reversed. If no battery
or connector maintenance has been performed
prior to the fuse blowing, the charger is
malfunctioning. If only one half link blows, the
charge rate will be low and the charger is
malfunctioning.
CAUTION: DO NOT USE THE CHARGER IF
THE OUTPUT IS LOW. BATTERIES WILL NOT
REACH FULL CHARGE, THEREBY INCREASING
THE POSSIBILITY OF A HARMFUL DEEP
DISCHARGE DURING THEIR NEXT USE.
3. AMMETER NEEDLE REMAINS AT MORE
THAN 40 AMPS FOR MORE THAN 90
MINUTES
This high charge rate is caused by misuse. The
charger is connected to a battery pack with a
system voltage lower than or amp-hour capacity
greater than specified on the charger. If
connected to a battery system of less than 36
volts, the charge rate will not taper and decrease
to 40 amps or less within 90 minutes. This is
caused when one or more of the batteries in the
system is connected reverse polarity.
4. THE CHARGER DOES NOT TURN OFF
New batteries or batteries charged in cold
temperatures may require an extended charge
time to achieve full charge. However, if the
charger runs for longer than the maximum listed
without shutting off, the charger is
malfunctioning. Turn the charger off by
disconnecting the input plug before
disconnecting the charging plug.
5. THE BUILDING AC LINE CIRCUIT BREAKER
OR FUSE BLOWS
This condition can be caused by a charger
problem, a "weak" fuse or circuit breaker
protecting the circuit, or an overloaded circuit. If
the building AC power fuse or circuit breaker
blows, connect the charger to other outlets (on
different circuits) in the building. If the charger
operates properly on other circuits, have a
qualified electrician inspect and test the original
circuit. If the charger causes other fuses or
circuit breakers (in the building) to blow, the
charger should be tested for a problem.

www.minutemanintl.com 6 31218C
WIRING DIAGRAM
PARTS LIST FOR 36 VOLT
AUTOMATIC BATTERY CHARGER
PART NO. 957740 120 VAC / 60 HZ
PART NO.
QTY. DESCRIPTION
31236S 1 CASE ASSEMBLY
17095S 1 TRANSFORMER ASSEMBLY
02390S 1 CAPACITOR, 6 MFD, 660 VAC
16946S 2 HEATSINK ASSEMBLY W/ 2 DIODES IN PARALLEL
08774S 1 FUSE ASSEMBLY
16823S 1 AMMETER, 50 AMP, W/ CORNER MOUNTING STUDS
24840S 1 TIMER KIT, 36 VDC, 120 VAC
* 04484S 1 RELAY, FOR ELECTRONIC TIMER
** 23385S 1 RELAY, FOR ELECTRONIC TIMER
04484S 1 TIMER KIT RELAY, 36 VDC, SPSTNO, 120 VAC
02028S 1 CORDSET BUSHING, 7W-2, FOR 14/3 INPUT CORDSET
02008S 1 CORDSET BUSHING, 8P-2, FOR 10/2 OUTPUT CORDSET
02506S 1 AC CORDSET, 14/3, 72" W/ 125V/15A PLUG
08329S 1 DC CORDSET, 10/2, 108", W/ SB175 GRAY PLUG
* FOR USE WITH CHARGERS BUILT BEFORE 04/04
** FOR USE WITH CHARGERS BUILT AFTER 04/04

www.minutemanintl.com 7 31218C
L I M I T E D W A R R A N T Y
Minuteman warrants each new Battery Charger for defects in material and workmanship for a period of one (1) year from
the date of manufacture of the complete unit. Repairs can be made at the Minuteman factory. To do so, send the defective
unit with transportation charges prepaid to:
Minuteman, Inc.
111 South Rohlwing Road
Addison, Illinois 60101
Attention: Service Department
For repairs made at other than the Minuteman factory, Minuteman will provide only the replacement parts. Defective parts
should be sent with transportation charges prepaid to the Minuteman factory at the previously mentioned address.
If the unit or parts are found in the reasonable judgment of Minuteman to be defective in material or workmanship, repair or
replacement will be made by Minuteman without charge for parts or labor. Repair or replacement will be at the discretion of
Minuteman, with replacements being made using current models or parts performing the equivalent function. Labor charges
other than those incurred at the Minuteman factory are not covered under this warranty. All expenses associated with
delivering defective items to the Minuteman factory and the expense of returning repaired or replaced items from the
Minuteman factory to the owner will be paid for by the owner. All warranty work accomplished at the Minuteman factory will be
completed with a reasonable time after receipt of defective items.
This warranty does not cover any semiconductor parts, such as diodes, which are vulnerable to electrical overloads beyond
the control of Minuteman.
This warranty does not cover any charger that has been subject to misuse, neglect, negligence, or accident, or operated in
any way contrary to instructions specified on the charger case and in the owner's manual. No claim of breach of warranty shall
be cause for cancellation of the contract of sale of any Minuteman charger. Minuteman assumes no responsibility for loss of
time, inconvenience, or other damage, consequential or otherwise, resulting from a defective charger. All implied warranties
(including merchantability) are limited in duration to the two years from date of manufacture warranty period.
Some states do not allow the exclusion or limitation of incidental or consequential damages; or limitations on how long an
implied warranty lasts, so the above limitations may not apply to you. This warranty gives you specific legal rights, and you
may also have other rights which vary from state to state.
Minuteman's obligation under this warranty is strictly and exclusively limited to the repair or replacement of defective items.
Minuteman issues this warranty in good faith and with full confidence in the workmanship and quality of Minuteman products.