Battery Charging Procedures
WARNING: WHEN BATTERIES ARE BEING CHARGED AN EXPLOSIVE GAS MIXTURE FORMS BENEATH THE COVERS OF EACH CELL. DO NOT SMOKE NEAR BATTERIES ON CHARGE OR WHICH HAVE RECENTLY BEEN CHARGED. DO NOT BREAK LIVE CIRCUITS AT TERMINALS OF BATTERIES ON CHARGE. CHARGER SHOULD BE TURNED OFF OR UNPLUGGED BEFORE DISCONNECTING. A SPARK WILL OCCUR WHERE LIVE CIRCUIT IS BROKEN. KEEP ALL OPEN FLAMES AWAY FROM BATTERY. DO NOT CHARGE FROZEN BATTERIES.Battery charging equipment varies from one manufacturer to the other. Therefore, follow specific charger manufacturer's instructions of proper setup and safety precautions.
When it is necessary to charge a sealed battery, the following safety precautions must be followed.
FIGURE 7:
1. If the battery is to remain in the vehicle, disconnect both battery cables, (Figure 7), negative cable first, to prevent electrical system damage.
2. Thoroughly clean the battery.
3. If a green dot is visible and the vehicle has not been cranked for an extended period of time recently, do not charge battery.
4. Do not charge the battery if the test indicator is clear or light yellow. Replace battery.
5. If the battery feels hot 125~F (52~C), or if violent gassing or spewing of electrolyte through the vent hole occurs, discontinue charging until excessive gassing stops. Then continue charging at a reduced charging rate.
CAUTION: CHARGE BATTERY ONLY UNTIL GREEN DOT APPEARS. DO NOT OVERCHARGE.
Slight tipping or shaking of battery may be necessary to make green ball appear.
6. Make sure all charger connections are clean and tight.
7. For best results, batteries should be charged while the electrolyte and plates are at room temperature. A battery that is extremely cold may not accept current for several hours after starting charger.
8. Charge the battery until green dot appears. See Battery Charging Rate and Time Table - Chart 5. Battery should be checked every half-hour while charging. Tipping or shaking battery may be necessary to make green dot appear.
9. After charging, battery should be tested as outlined in "Load Test" procedure.
WARNING: SOME CHARGERS FEATURE VOLTAGE SENSITIVE SWITCHES. A COMPLETELY DISCHARGED BATTERY MAY NOT HAVE ENOUGH VOLTAGE TO ACTIVATE THIS CIRCUITRY ENOUGH, MAKING IT APPEAR THAT BATTERY WILL NOT ACCEPT CHARGING CURRENT.
Follow the charger manufacturer's instructions telling how to by-pass or override circuitry so that charger will turn on and charge a low-voltage battery.
Charging Time Required
The time required to charge a battery will vary depending upon the following factors:
1. Size of Battery -- A completely discharged large heavy-duty battery requires more than twice the recharging as a completely discharged small passenger car battery.
2. Temperature -- A longer time will be needed to charge any battery at 0~F (-18~C) than at 80~F (27~C). When a fast charger is connected to a cold battery, current accepted by battery will be very low at first. Then, in time, the battery will accept a higher rate as battery warms.
3. Charger Capacity -- A charger which can supply only five amperes will require a much longer period of charging than a charger that can supply 30 amperes or more.
4. State-Of-Charge -- A completely discharged battery requires more than twice as much charge as a one-half charged battery. Because electrolyte is nearly pure water and a poor conductor in a completely discharged battery, current accepted by battery is very low at first. Later, as charging current causes electrolyte acid content to increase, charging current will likewise increase.
FIGURE 8:
Charging A Completely Discharged Battery (Off The Vehicle)
The following procedure should be used to recharge a completely discharged battery. Unless procedure is properly followed, a good battery may be needlessly replaced.
1. Measure voltage at battery terminals with a voltmeter, accurate to 1/10 volt. (Figure 8.) If below 10 volts, then charge current will be low and it could take some time before it accepts a current in excess of a few milliamperes. Such low current may not be detectable on ammeters built into many chargers.
2. Set battery charger on high setting.
3. Connect charger leads with correct polarity. Some changes feature polarity protection circuitry which prevents charging unless charger leads are connected to battery terminals correctly. A completely discharged battery may not have enough voltage to activate this circuitry, even though leads are connected properly, making it appear that battery will not accept charging current. Therefore, follow specific charger manufacturer's instructions telling how to by-pass or override circuitry so that charger will turn on and charge a low-voltage battery.
4. Battery chargers vary in the amount of voltage and current they provide. For time required for battery to accept measurable charger current at various voltages refer to Charge Rate - Chart 6. If charge current is still not measurable at end of charging times, the battery should be replaced. If charge current is measurable during charging time, the battery is considered to be good and charging should be completed in the normal manner.
CHARGE RATE - CHART 6
Voltage Hours
16.0 volts or more up to 4 hrs.
14.0 to 15.9 volts up to 8 hrs.
13.9 volts or less up to 16 hrs.
5. It is important to remember that a completely discharged battery must be recharged for a sufficient number of ampere hours (ah) to restore it to a usable state. As a general rule of thumb, divide reserve capacity rating of the battery by the charge being applied to determine the length of time the battery needs to be charged. If you are using a 10 Amp charger on a 110 minute reserve it would take 11 hours. (110/10 = 11 ampere hours.)
6. It is recommended that any battery recharged by this procedure be Load Tested to establish serviceability.
WARNING: WHEN CHARGING ON "HIGH" BOOST SETTING BATTERY MUST BE CHECKED EVERY 30 MINUTES TO INSURE THAT VIOLENT GASSING OR SPEWING OF ELECTROLYTE THROUGH VENT HOLES DOES NOT OCCUR. IF VIOLENT GASSING RESULTS, CHARGE RATE MUST BE REDUCED TO A LEVEL WHERE EXCESSIVE GASSING STOPS.
POLICY: Information only.