BATTERY STATE OF CHARGE
The battery must have an adequate state of charge before a valid battery
load test can be performed. The state of charge can be measured with
a hydrometer (see Appendix A page 16), or checked by the “state of
charge” scale on the voltmeter for sealed batteries.
Read the 12 volt range (12 Volt Batteries) or the 6 volt range (6 Volt
batteries) on the voltmeter, If the meter reads on the left side, in the red
zone of the “state of charge” scale, the battery must be charged. See
Appendix B page 17 for charging. Charge at a current rate as shown
in Appendix B. This rate is determined by battery category type, which
relates to reserve capacity in minutes.
After charging the battery, the surface charge must be removed before
testing can begin. Surface charge will cause a higher voltage reading,
which is incorrect. To remove the surface charge, turn the load knob to
apply 1/2 the cold crank rating load or 3 times the amp-hour rating to
the battery for 5 seconds. Wait several minutes after removing load and
check “state of charge”. If the meter reads in the charge zone, replace
battery (see example above). If the voltmeter reads in the “test” band
(see example below), the battery is ready for the “battery load test”.
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