Battery Inspection, Charging Procedure & Recommendations & Test Procedures Information
BATTERY VISUAL INSPECTION1. Make sure ignition switch is in "Off" position and all battery feed accessories are off.
2. Disconnect battery cables at battery Negative first.
3. Remove battery hold-down clamp and remove battery from vehicle.
WARNING: CARE SHOULD BE TAKEN, IN THE EVENT BATTERY CASE IS CRACKED OR LEAKING, TO PROTECT HANDS FROM THE ELECTROLYTE. A SUITABLE PAIR OF RUBBER GLOVES (NOT THE HOUSEHOLD TYPE) SHOULD BE WORN WHEN REMOVING BATTERY BY HAND.
4. Clean top of battery with a solution of clean warm water and baking soda. Scrub area with a stiff bristle brush and wipe off with a cloth moistened with ammonia or baking soda in water.
5. Inspect battery case and cover for cracks. If cracks are present battery must be replaced.
FIGURE 3:
6. Inspect battery tray for damage caused by loss of acid from battery. If acid damage is present it will be necessary to clean area with same solution as described in Step 4.
7. Clean battery post with a suitable battery post cleaning tool (Figure 3).
FIGURE 4:
8. Clean the inside surfaces of the terminal clamps with a suitable battery terminal cleaning tool. Replace damaged or frayed cables and broken terminal clamps (Figure 4).
9. Inspect battery for proper or damaged hold down ledge.
10. Install battery in vehicle making sure that the battery is properly positioned on the battery tray.
11. Install battery hold-down clamp, making sure that it is properly positioned on battery and tighten bolt to 12 N-m (100 inch pounds).
12. Connect cable clamps to battery post making sure top of clamp is flush with top of post.
13. Tighten clamp nut securely.
14. Coat all connections with light mineral grease after tightening.
CHARGING PROCEDURES
WARNING: WHEN BATTERIES ARE BEING CHARGED AN EXPLOSIVE GAS MIXTURE FORMS BENEATH THE COVER OF EACH CELL. DO NOT SMOKE NEAR BATTERIES ON CHARGE OR WHICH HAVE RECENTLY BEEN CHARGED. DO NOT BREAK LIVE CIRCUITS AT THE TERMINALS OF THE BATTERIES ON CHARGE. A SPARK WILL OCCUR WHERE THE LIVE CIRCUIT IS BROKEN. KEEP ALL OPEN FLAMES AWAY FROM THE BATTERY.
When it is necessary to charge a sealed battery, the following safety precautions must be followed:
1. Do not charge battery if green dot is visible except immediately following prolonged cranking.
2. Do not charge the battery if the hydrometer (test indicator) is clear or light yellow. Replace battery.
3. If the battery feels hot (125~F-52~C), or if violent gassing or spewing of electrolyte through the vent hole occurs, discontinue charging or reduce charging rate.
CAUTION: CHARGE THE BATTERY ONLY UNTIL THE GREEN DOT APPEARS. DO NOT OVERCHARGE.
Slight tipping or shaking of the battery may be necessary to make the green ball appear. Temperature of the battery will affect the charging rate, and most charging equipment will not charge at a constant rate. For example, if the charger starts at 30 amperes and drops off to 10 amperes after 1 hour, the average current for that hour was 20 amperes. The actual boost charge was 20 amperes hours. The sealed battery can be fast charged or slow charged with ordinary chargers in the same manner as conventional batteries. Either method will restore the battery to full charge.
Slow Charging Batteries
If adequate time is available, the slow charging method should be used in recharging a discharged battery.
There are many types of battery charging equipment available. Be sure to follow the instructions of the equipment manufacturer for the necessary preparations and precautions. However, the following items should be observed when slow charging the battery with any type of equipment:
1. If the battery is to remain in the vehicle, disconnect the cables at the battery negative cable first to prevent damage to the electrical system during charging.
2. Thoroughly clean the battery. Refer to "Battery Visual Inspection."
Fast Charging Battery
If adequate time for a slow charge is not available, a high rate fast charge is permissible and will give a sufficient charge in one hour enabling the battery and alternator to continue to carry the electrical load. If the battery is to remain in the vehicle, disconnect the cables at the battery negative cable first to prevent damage to the electrical system during charging. The manufacturers of high rate charging equipment generally outline the necessary precautions and some models have thermostatic temperature limiting and time limiting controls. Make sure their instructions are followed.
Stop charging when green dot appears or when maximum charge shown below is reached:
Battery Slow Charging Fast Charging
335 amp 10 hrs. @ 4 amps 2.0 hrs. @ 20 amps
4.0 hrs. @ 10 amps 1.2 hrs. @ 30 amps
370 amp 10 hrs. @ 5 amps 2.5 hrs. @ 20 amps
5.0 hrs. @ 10 amps 1.5 hrs. @ 30 amps
430 amp 12 hrs. @ 5 amps 2.7 hrs. @ 20 amps
6.0 hrs. @ 10 amps 2.0 hrs. @ 30 amps
500 amp 12 hrs. @ 5 amps 3 hrs. @ 20 amps
6.0 hrs. @ 10 amps 2 hrs. @ 30 amps
CHARGING RECOMMENDATIONS
Do not charge frozen battery (batteries may freeze at temperatures of +20~F or colder if the state of charge is very low). If it is suspected that a battery is frozen, move the battery indoors to a heated area for at least two hours before charging. Do not place battery near open flame.
Battery Fast Charger Recommendations
^ 40-50 amperes minimum charge rate capability for discharged battery.
^ To prevent overcharge, a timer (one or two hour) or voltage regulator (18 volt maximum) to stop or reduce the charge rate as battery is recharged.
^ Ammeter or charge indicator. (Extremely cold and some completely discharged batteries may appear not to accept a charge on this meter. In reality, some small current is being accepted and the meter is not sensitive enough to register it. Continue charging and a charger rate will begin to show in time.)
^ Automatic polarity protection. Some of these devices require some activating voltage to become operational, therefore, a by-pass or override feature is desirable for totally discharged batteries with extremely low terminal voltage.
Charging Time Required
The time required to charge a battery will vary depending upon the following factors:
^ Size of battery - a completely discharged large heavy-duty battery requires more than twice the recharging as a completely discharged small passenger car battery.
^ Battery temperature - a longer time will be needed to charge any battery at 0~F than at 80~F. When a fast charger is connected to a cold battery, the current accepted by the battery will be very low at first, then in time the battery will accept a higher rate as the battery warms.
^ Charger capacity - a charger which can supply only 5 amperes will require a much longer period of charging than a charger that can supply 30 amperes or more. Charge rates as high as 50 amperes are generally satisfactory as long as spewing of electrolyte out of the vents does not occur and the battery does not feel excessively hot (over 52~C, 125~F).
^ State of charge - a completely discharged battery requires more than twice as much charge as a half-charged battery. Because the electrolyte is nearly pure water and a poor conductor in a completely discharged battery, the current accepted by the battery is very low at first. Later, as the charging current causes the electrolyte acid content to increase, the charging current will likewise increase.
Battery chargers vary in the amount of voltage and current they provide. Thus, the time required for the battery to begin to accept measurable charger current will also vary.
REMEMBER, EVEN WITH CHARGER ON HIGHEST SETTING, IT MAY BE SEVERAL MINUTES BEFORE CHARGING CURRENT IS MEASURABLE. HOWEVER, THE CHARGING CURRENT WILL THEN INCREASE RAPIDLY TO NORMAL VALUES IF A GOOD FAST CHARGER IS USED.
TEST PROCEDURES
Load Test
1. Observe indicator for presence of green dot. If not visible, charge battery prior to testing.
2. Observing polarity, connect a voltmeter and a battery load tester across battery terminals.
3. Apply a 15 amp load or turn on headlamps for 15 seconds to remove surface charge from the battery. Remove the load.
4. Wait 15 seconds to let battery recover and apply load. See specifications for proper load.
5. Read voltage after 15 seconds with specified load applied, then disconnect load.
6. If voltage does not drop below the minimum listed in the Load Test Chart, the battery is good and should be returned to service. (The battery temperature must be estimated by feel and by the temperature the battery has been exposed to for the preceding few hours.)
7. If the battery passes the load test, its in good condition. No further tests are necessary. If it fails the load test, check further to see whether it should be charged or replaced.
LOAD TEST CHART
Minimum Voltage Temperature
F~ C~
9.6 70 and above 21 and above
9.5 60 16
9.4 50 10
9.3 40 4
9.1 30 -1
8.9 20 -7
8.7 10 -12
8.5 0 -18
Open Circuit Voltage Test
If the battery fails the load test, then check the charge in it. The open circuit or no-load voltage is a good measure of the charge after the battery has stabilized. This takes a couple of minutes after the load test has been completed. This voltage reading shows the battery charge thus:
BATTERY CHARGE PERCENT CHART
Open Circuit Volts Percent Charge
11.7 volts or less 0%
12.0 25%
12.2 50%
12.4 75%
12.6 or more 100%
Because the change of voltage with charge is small, most battery testers use special voltmeters with scales expanded to better show the percent charge. If the charge is 75% or more, the battery is considered substantially charged. If it failed the load test with this 75% charge or more, it should be replaced. On the other hand, if the charge in the battery is under 75% it should be charged and load tested again. If it fails the load test again it should be replaced.
If it then passes the load test, it should remain in service. Proceed to Possible Causes of Battery Failure in Vehicle.
Possible Causes of Battery Failure in Vehicle
Battery failures are often not the fault of the battery, but caused by certain conditions in the vehicle. Foremost among these are:
1. Corroded battery posts or connectors - when charging a battery (or when replacing one) the battery cables should be removed from the posts. After this is done, always clean the posts and the cable connectors with a brush or suitable tool. The corrosion film that forms on the posts and connectors can prevent good electrical contact with the battery, even when the connections are tight.
2. Electrical leakage - vehicles normally have a small continuous drain on the battery of as much as 15-20 milli-amperes due to digital clocks and solid state devices. In addition, there may be a condition in the car's electrical system that drains the battery even when all accessories are turned off. To check for such leakage, turn off all accessories in the car and shut doors, trunk, and turn off all lights. If there is an underhood lamp, remove its bulb. Now you can check for leaks by one of the following methods:
a. At the battery, disconnect the cable that connects to the vehicle starter (the positive (+) cable). With an ohmmeter measure the resistance between the disconnected cable end and the vehicle's chassis or engine block. A reading of under 100 ohms indicates a leak of .1 amp or more which should be corrected.
b. At the battery, disconnect the cable that connects to the engine block (the negative (-) cable) on modern American vehicles. Connect a low resistance voltmeter (about 100 ohms per volt resistance) between the engine block and the disconnected battery post. An upscale reading of 6 volts or more indicates a leak of .1 amp or more which should be corrected.
The voltmeter test cannot be made with high resistance meters which read battery voltage through accessories such as electric clocks and voltage regulators.
Some vehicles may have an electric clock which turns on momentarily every couple of minutes to wind. When this happens touch the disconnected cable briefly to the disconnected post to wind the clock.