Click to enlargepadFull Service Charger Info

LEWCO BATTERY CHARGER MANUAL… Describes two different types of battery chargers:

The original standard LEWCO Battery Charger is a transformer controlled unit.

The Full Service (F.S.) model is a load-handling electronically controlled unit.

EFFICIENCY…Due to the extremely high forward-to-back current ratio, silicon rectifiers achieve rectification efficiencies up to 99% at power frequencies. The high efficiency is characterized by forward conduction voltage drops of approximately one volt, hence higher output voltages, and reverse currents of the order of micro amperes at the peak inverse voltage.

HERMETICALLY SEALED…Each silicon diode is hermetically sealed. This seal is a great advantage to the marine field, for the ever present salt air and moisture cannot damage the silicon diode.

CHARGER CABINETS…The cabinets used are hot zinc dipped and powder coated.

CHARGER POWER…The charger, without damage to itself, can be connected to discharged banks of batteries and will fully charge them on a perfect taper curve, automatically reducing charging rate to a trickle as batteries become charged.

INSTALLATION…Designed as a permanent installation in the boat and a permanent connection to the battery bank.

LINE VOLTAGE…Compensation tap switch incorporated so that the converter may be operated efficiently from either extremely high or low line voltages.

D.C. AMMETER…Ammeter is incorporated in the output circuit to indicate current being supplied to batteries and accessories.

TRANSFORMER…The transformer are designed for marine use and incorporate isolated primary and secondary coils. This prevents electrolysis and eliminates shock on the charger lines.


The LEWCO Standard Battery Charger may be installed on bulkhead or hull in any convenient location near the batteries in such a manner as to allow free circulation of air through the bottom and out of the top of the charger chassis. The unit must not be mounted directly over batteries.

The charger requires 50- to 60- cycle single-phase 115 AC power as designated by the nameplate. Terminal post are provided within the charger for connection of the AC input and the DC output cables. 230 AC volt available.

In operation, the charger is connected to the AC source and will start to charge the battery at some rate of its full capacity, depending on the state of charge of the battery. The one to six position switch on the front of the LEWCO BATTERY CHARGER is to allow different charge rates and to compensate for AC line voltage. The #2 position is the normal automatic position.

If , over a period of a few days, the batteries do not come up to a full charge on hydrometer, move to the next higher tap, or if the charger does not shut down to a float charge and excessive gassing occurs, the tap should be moved to the next lower tap.

Under normal conditions, a fully discharged 65- to 90- amp battery will be recharged in approximately 12 to 24 hours. Any additional time the charger operates will be a trickle rate.

The LEWCO SILICON DIODE BATTERY CHARGER requires no contact lubrication or maintenance.

A direct current ammeter has been incorporated into the direct current output of the charger so that the operation of the charger may be observed at all times. Also, an AC neon indicator light is mounted directly above the ammeter and remains on as long as the charger is in operation.

For complete protection of the unit, the AC input and the DC output lines have circuit breakers on the front panel of the charger.


The terminal panel with the terminals on it is located inside the cover. Remove the top panel screw and the faceplate will come forward from the top. The DC terminals are marked plainly with their polarity. Connect the positive terminal to the positive terminal of the batteries and the negative terminal to the negative terminal of the batteries. BE SURE YOU ARE RIGHT! If the battery terminals are unmarked, corroded, or unreadable, check the polarity with a voltmeter. Connections from the LEWCO CHARGER to the batteries are always POSITIVE TO POSITIVE and NEGATIVE TO NEGATIVE. The two AC terminals are usually connected to a cable long enough to reach the AC dock outlet, except on boats already wired for AC lines. Use marine-approved wire and clamps all internal wiring securely to the hull and bulkheads.


The Original standard LEWCO Battery Charger is designed to charge Wet cell batteries only. Gel cell batteries should be charged with F.S. LEWCO BATTERY CHARGER models. The F.S. LEWCO BATTERY CHARGER can charge Wet and Gel cell batteries. The standard LEWCO Battery Charger can be updated to FS technology if in serviceable condition.

The recommended size of wire is shown below

MODELS AC INPUT DC OUTPUT 12V-20 amp #16 #10 12V-40 amp #12 #8 12V-80 amp #10 #4 24V-20 amp #12 #10 24V-40 amp #12 #8 32V-20 amp #12 #10 32V-40 amp #10 #8 115V-10 amp #10 #10


When you connect a LEWCO CHARGER to a fully charged set of batteries, there will be no indication anything is happening because it supplies current only when it is needed. To bring the charger into operation, turn on the accessories and let them run for a short period. This will give you a reading on the ammeter. When the charger replaces the current lost, it will return to a reading of one milliampere for every amp-hour of batteries, commonly called a float condition.


After letting the charger operate for a period of 48 hours in #2 position, if you find the reading on the hydrometer indicates batteries not quite at full charge and the ammeter is reading “zero” this would indicate that the charger has shut off too soon. The following compensation procedure should be followed. Set tap switch to #3 position for 24 hours and repeat the hydrometer test.


Since the LEWCO BATTERY CHARGER operates on battery voltage, the batteries should be checked periodically for dead cells. Should a dead cell appear, replace immediately with a new battery.


The function of the Automatic Charger Divider (ACD) is to charge three banks of batteries at once, yet not have them paralleled. This is accomplished as shown in the diagram below by charging through the diodes in the forward direction. Therefore, the charge can go through the diodes to the batteries, yet the batteries cannot back up though the diodes and assist one another as in parallel. This multiple-battery divider is built into the ACD models and eliminates the need for providing switches and fuses that one must remember to turn off before using the boat. In addition to the above features, we have one other important feature that we gain in the use of the charger divider. Unlike batteries charging in parallel, the divider allows the lowest charged battery to receive the charge first, until it comes up to match the next- lowest charged battery. Then the batteries are on the line and come up together to match the third battery. When they all finish charging the machine tapes to nil charge and the batteries are ready to go


A load-handling, electronic-switching charger, designed with a black and white face, is available in 115- or 230-volt AC, 50/60 Hz. It is self-regulating to compensate for unstable incoming AC line power between 110 and 125 volts.

The LEWCO FULL SERVICE model will cycle down to a slow, variable pulse charge to finish and maintain batteries at a full capacity without abnormal water loss.

LEWCO FULL SERVICE models are available in 12-, 24-, 32-, and 36-volt systems, 20 or 40amp. The 12-volt machine producing 80 amps tops the new line. All models can be ordered for single or multiple bank operation.

The LEWCO FULL SERVICE model can be used with GEL CELL systems by keeping it in the #3 position. The higher position could be used for faster charge recovery but should be returned to the #3 position upon completion of charge.

GEL CELL and WET CELL batteries may be serviced from the same charger. Due to the physical differences between the two types of cells, they can NOT be mixed in a bank either in series or parallel.

The LEWCO FULL SERVICE model still retains the desirable feature of hands-on control over the rate of charge. A power tap switch with six positions allows you to control the output of the machine. The #1 tap position is for a very low battery condition, “START UP CHARGE.” The #2 and #3 position are for the normal maintenance charge, used when the vessel is in storage or weekend use. The #4 and #5 positions are for “LIMITED LOAD HANDLING” when AC power is available. The #6 position is for “HANDS-ON CHARGING” to compensate for low AC line voltage and to reduce the number of hours needed to recharge the battery using generator of shore power.


The lower voltage shown is for storage. Full Service models are set for active battery systems.

SYSTEM 12VOLT 24VOLT 32VOLT 36VOLT Cells 6 12 16 18 Floats 13.4 26.7 35.8 40.1 Volts to to to to 13.8 27.6 36.8 41.4


On multi-output (ACD) chargers, connect positive output terminal to one bank of batteries only.


A multiple output from the charger will not function correctly to a single bank of batteries. A dual path from the charger would double the pulse rate to the batteries, increasing the float voltage.


Will the charger damage my alternators if I don’t disconnect my batteries? What would I damage if I started my engine and forgot to turn off the charger?

The charger will not damage the alternators in your boat because it will be permanently connected to your batteries in the proper polarity and cannot accidentally send a reverse polarity to your alternators. The rule DISCONNECT BATTERY BEFORE CHARGING “ applies primarily to the automotive industry where in a service station an inexperienced person might connect a high-rate, fast charger to your battery in reverse and burn out the alternator diodes.

If you start your boat engines with the LEWCO RECTIFIER charging on your batteries, it won’t hurt a thing. The charger will be trying to help supply the power to start the engine and could charge more than the rated output. It might trip out the breaker in the charger, but it won’t hurt anything.

The charger has six positions on the front panel tap switch. Are they all automatic? Which one should I use?

The #2 position is the normal automatic position. This is where you should leave it when you are leaving the boat unattended for days or weeks. Sometimes, if you are floating refrigeration or other similar loads, you might require the next higher position, #3

The #4, #5 and #6 position overrides the automatic #2 position and will be at a higher rate of charge. Thus they will not taper completely back to zero of charge. This override is a very desirable feature for the purpose of being able to set the charger higher than automatic, in the event for example, you took a trip and ran the batteries low, than wanted to use the boat again right away, or the next day. You can set it up to #4, #5 or #6 non automatic position and do as much charging as you can in the short time you have. If you have a 115-volt AC generator aboard and start it periodically through the day for cooking, etc., you want to do as much charging into your batteries as you can with the charger in these short periods. This again is when you will want to set it in the #4 #5, or #6 position when you get back to the slip. TESTING YOUR BATTERY

Hydrometer readings reflect the batteries’ “state of charge.”

Specific Gravity of 1.265 = Full Specific Gravity of 1.200 =Half full Specific Gravity of 1.150 = Discharged

Unless you are looking for a battery problem, it is not necessary to test all cells – just pick one cell on the battery and use it to monitor.

Since we consider voltage and stage of charge two different things, we feel you are better informed on battery condition by using a hydrometer.


After the charger has been in service a number of years, the “Power On” light may begin to flicker. This is a sign that pilot light is wearing out, and it is just a matter of changing the complete neon pilot light assembly.


1. Comply with the general requirements of “Fire Prevention Standards for “Motor Craft” relative to electrical equipment. 2. The unit should be installed in a dry, accessible, and adequately ventilated location not directly over batteries but away from any contact with bilge water. 3. The unit should be securely bolted to sound partitions or other structural parts. 4. In compliance with requirements of the National Electrical Code, insulated conductors for use in wet locations should be used for connection with shore power.

We are familiar with these safety regulations pertaining to electrical and fuel systems.

The LEWCO silicon diode (electronic battery charger ) conforms to the following paragraphs of the Coast Guard safety requirements:

183.430 Conductors. We fulfill the requirement in accordance with wire gauge sizes and insulation. 183.435 does not apply to our electronic equipment. 183.440 does not apply to our electronic equipment. 183.445 does not apply to our electronic equipment. 183.410 Ignition Protection. The LEWCO charger, when installed in accordance with paragraph B-1 and B-3 of 183.410, is in accordance with Coast Guard safe-boating standards. NOTE: 183.410 (A) Gasoline-engined vessels should not mount LEWCO chargers in compartments With gasoline environment fuel vapors. However, for diesel-fueled vessels, the LEWCO charger Can be mounted in the engine compartment.

Thank you for your interest in our products, and we know that you, as well as we, want to promote SAFE BOATING.

Lewco Electric Co Inc. 456 Old Newport Blvd.

Newport Beach, Ca 92663