Murphy BCEG-24-20 Using Correct Size Battery Charger, Factors Contributing to Electrolyte Loss

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Using Correct Size Battery Charger

The battery charger will need to provide both the standing load and minimum charge current. If a charging current of 2 amps is required, and the standing load is 1 amp, then the charger needs to be able to output a total of 3 amps.

Refer to genset manual for sizing of battery chargers to generator set. If installing your own chargers, lead acid battery manufacturers recommend the following:

Minimum charge current should be approximately 5% battery AH capacity.

Maximum charge current to be equal to 25% battery AH capacity

NOTE: When batteries are normally charged by a charging alternator, a float battery charger rated at lower than the minimum charge current is sufficient to keep batteries in fully charged state.

Factors Contributing to Electrolyte Loss

Physical damage to cells can cause electrolyte to leak or evaporate.

High charging voltages will evaporate electrolyte.

Check charging voltage against battery type and voltage.

WARNING: If the batteries are being used at above 20° Celsius, the chargers output voltage should be temperature compensated at -3mV/°F/Cell.

Battery Life

Two possible methods can be used for determining battery life:

Using Hydrometer

Using a digital DC voltmeter

Follow these steps to check battery life.

1.Fully charge the batteries.

2.Disconnect batteries and leads and leave for 24 hours.

3.Measure either specific gravity (hydrometer) or terminal voltage (voltmeter) and compare with the table on the following page.

4.If time is limited due to on-site testing, remove surface charge by either applying a 20 amp load for 3 minutes or crank engine for 10 seconds, then disconnect batteries and leads and leave for minimum of 10 minutes.

Section 75

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Contents Guardian Battery Charger Series Before Beginning Installation of this Murphy Product Table of Contents Page Safety Instructions General Safety InstructionsPersonal Precautions Prior to Installation / CommissioningCharger Location and Connection Temperature Compensation Charge Fail and AlarmsGeneral Product Information Auto Boost Equalizing OperationDimensions Battery Charged ConditionCurrent Limiting Installation and Mounting Instructions Mounting hole dimensionsOperating Instructions Terminal Connection InformationAutomatic Battery Charger Connection to Power SupplyConnection to Batteries Disconnection of BatteriesOver Voltage, Under Voltage, and Charge Fail Connection FusesTroubleshooting Current Flow from Charger to Battery Voltage Rise at Battery TerminalsMeasuring Charging Voltage and Current Output VoltageBattery Life Using Correct Size Battery ChargerFactors Contributing to Electrolyte Loss Charge Specific Gravity Voltage DC on 12V battery Specifications Power SupplyDC Charge Output Charge Fail OutputSection 00-02-0615 02-29-08