Lester LESTRONIC II 17910 User manual

Operating Instructions 101537C
LESTRONIC II FULLY AUTOMATIC
BATTERY CHARGER
MODEL 17910 TYPE 48LC21-6ET
Specifications
AC Input: 108-128 Volts AC, 12 Amp, 60 Hertz, single-phase
DC Output: 48 Volts DC, 21 Amp
Connections: Input - 6 or 9 ft. AC input cord with NEMA 5-15 grounded plug
Output - 8½ ft. or longer 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 DV/DT 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 conservative percentage of their rating.
•Convection-cooled design for maximum reliability and minimum maintenance.
INTRODUCTION
The Lestronic II 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
DV/DT 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 fully charged and the
charger turns off.
INITIAL INSTALLATION
The AC line to which the charger is to be connected
must be capable of supplying 15 amperes to this
charger.

Operating Instructions 201537C
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.
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 a 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 charger 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 and 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
ELECTRIC SHOCK, KEEP THE CHARGER DRY.
DO NOT EXPOSE IT TO RAIN, POWER WASH
DETERGENTS OR SPRAY. FOR STORAGE,
KEEP THE 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 RISK OF AN 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 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
A
B
C
CONNECTED
TO COVER
OF GROUNDED
OUTLET BOX
ADAPTER
COVER OF
GROUNDED
OUTLET BOX
GROUNDING
BLADE GROUNDED
OUTLET
GROUNDING
MEANS
NOTE: The use of the adapter shown in Figures B
and C is not permitted in Canada.
If a grounding type 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 48 VOLT, 24 CELL, SERIES
CONNECTED WET LEAD-ACID SYSTEM WITH A
CAPACITY OF 140 TO 270 AMPERE-HOURS (20
HR. RATE). OTHER TYPES OF BATTERIES MAY
BURST CAUSING PERSONAL INJURY AND
DAMAGE.

Operating Instructions 301537C
ATTENTION: Utiliser pour charger
uniquement les accumulateurs au plomb a
electrolyte liquide. D'autres types d'accumu-
ateurs 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
toucher les parties non isolées du connecteur de
sorti ou les bornes non isolées de
l'accumulateur.
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 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 CONDUCTORS 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 16 to 25
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.
It the batteries are heavily discharged and the
AC input line voltage is higher than nominal, the
initial charge rate may exceed 25 amperes.
Under normal conditions, the charge rate will
taper to less than 25 amperes within 30 minutes.
If the ammeter still reads more than 25 amperes
after 30 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
30 MINUTES WITH THE AMMETER READING IN
EXCESS OF 25 AMPS. THIS IS MISUSE AND
WILL CAUSE OVERHEATING AND TRANS-
FORMER BURNOUT.
4. The charge rate will decrease to 4 to 9 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 9 amps. Each cell
accepts charge differently; normal charging with
the ammeter reading in the 4 to 9 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 4 to 9 amps range on the
ammeter. The electronic timer still determines
when the batteries have reached their maximum
state of charge and turn 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 battery 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.
Under normal operating conditions, the
maximum necessary charger time is 10 to 12
hours.
This normal charge time is 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).

Operating Instructions 401537C
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 to 5
amps), and additional time is required to
achieve equalization of all battery cells.
Refer to a qualified service agent if the
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
DC OUTPUT CONNECTOR CONNECTED WHILE
UNATTENDED FOR TWO 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 turned off, disconnect the
DC output plug from the receptacle by grasping
the plug body and pulling the plug straight out of
the receptacle.
WARNING: TO AVOID DAMAGE TO THE DC
OUTPUT PLUG AND CORD, DO NOT PULL ON
THE CORD.
BATTERY STORAGE MAINTENANCE
When the machine is not in use, charge the batteries
once each 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
EYE SHIELDS AND CLOTHING 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 one of the
6 volt batteries reverse polarity 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 level 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 top 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 charged 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.

Operating Instructions 501537C
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 frame.
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 bright. Due to heating
and discharge rates, bolted connections loosen
over time. Retighten the connections twice
yearly to the manufacturer's specified torque.
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 25 AMPS FOR MORE THAN 30
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 DC 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 25 AMPS FOR MORE THAN 30
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 48
volts, the charge rate will not taper and decrease
to 25 amps or less within 30 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 discon-
necting the charging plug.
5. THE BUILDING AC LINE CIRCUIT BREAKER
OR FUSE BLOWS

Operating Instructions 601537C
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.
WIRING DIAGRAM
CAPACITOR
TRANSFORMER
FUSE
ASSEMBLY AMMETER
DIODE HEATSINK ASSEMBLY
ELECTRONIC
TIMER KIT
GREEN
GROUNDED
AC INPUT
WHITE
BLACK
+
-
BATTERIES
TAN
TAN
TAN
BLACK (-)
TAN
TAN
WHITE OR RED (+)
BLACK
BLACK
1
2
3
GREEN
TO
CASE GROUND
4
DC CORDSET
AC
CORDSET
SECONDARY
PRIMARY
ORANGE
BROWN
RED
BLACK
CABLE ASS'Y
CONTROL
1
5
4
3
2
TAN
BUSHING
INPUT
BUSHING
OUTPUT
RELAY
L2120S18

Operating Instructions 701537C
PARTS LIST FOR LESTRONIC II CHARGER
MODEL 17910 TYPE 48LC21-6ET
120 VAC / 60 HZ
PART NO. QTY. DESCRIPTION
22192S 1 CASE ASSEMBLY, MODEL 17910
17915S 1 TRANSFORMER ASSEMBLY, 48LC21-6, 120/60
02390S 1 CAPACITOR, 6 MFD, 660 VAC/70C, 600 VAC/90C
16354S 1HEATSINK ASSEMBLY, W/ DIODES
08776S 1 FUSE ASSEMBLY
21461S 1 AMMETER, 0-25 AMP, CORNER STUD MOUNT
16369S ALT AMMETER, 0-30 AMP, CORNER STUD MOUNT
17675S 1 ELECTRONIC TIMER KIT, 48 VDC, SHELF
21239S 1 RELAY, 48 VDC, SPSTNO, 15A/250V, FLANGE MOUNT
16324S 1 CONTROL CABLE ASSEMBLY W/ EDGE CONNECTOR
02028S 1 INSULATOR BUSHING FOR 12/2 DC CORDSET, 7W-2
03894S 1 INSULATOR BUSHING FOR 14/3 AC CORDSET, 7K-2
22653S 1 AC CORDSET, 14/3, 104", 5-15P MOLDED PLUG
22632S 1 DC CORDSET, 12/2, 113", BLUE SB175 PLUG W/ KEY
08020S 1 DC CORDSET, 12/2, 108", LESTER YELLOW PLUG
08045S 1 DC RECEPTACLE ASSEMBLY FOR LESTER YELLOW PLUG
L I M I T E D W A R R A N T Y
Lester Electrical warrants each new Lester Battery Charger for defects in material and workmanship for a period of two (2)
years from the date of manufacture of the complete unit. Repairs can be made at the Lester factory. To do so, first obtain a
"Return Material Authorization" number by calling the Service Department of Lester Electrical (402 477-8988) or by e-mailing
[email protected] and send the defective unit with transportation charges prepaid to:
Lester Electrical
625 West A Street
Lincoln, NE 68522-1794 USA
Attention: Service Department
RMA #
For repairs made at other than the Lester factory, Lester will provide only the replacement parts. Defective parts should be
sent with transportation charges prepaid to the Lester factory at the address noted above.
If the unit or parts are found in the reasonable judgment of Lester to be defective in material or workmanship, repair or
replacement will be made by Lester without charge for parts or labor. Repair or replacement will be at the discretion of Lester,
with replacements being made using current models or parts performing the equivalent function. Labor charges other than
those incurred at the Lester factory are not covered under this warranty. All expenses associated with delivering defective
items to the Lester factory and the expense of returning repaired or replaced items from the Lester factory to the owner will be
paid for by the owner. All warranty work accomplished at the Lester 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 Lester. Warranty on parts not manufactured by Lester, which include, but are not limited to, timers and
ammeters, is limited to the period specified in the original manufacturer's warranty.
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 Lester charger. Lester 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.
Lester's obligation under this warranty is strictly and exclusively limited to the repair or replacement of defective items.
Lester issues this warranty in good faith and with full confidence in the workmanship and quality of Lester products.