Filter
Top Products
• 9 •
CALCULATING CHARGE TIME14.
To determine the time needed to fully charge your battery, you must
rst determine the battery’s charge level with a hydrometer or electronic
Percent-of-Charge Tester. The following table will help you convert hy-
drometer readings to percent of charge values.
Specic Gravity Percent of Charge Percent of Charge
Needed
1.265 100% 0%
1.225 75% 25%
1.155 25% 75%
1.120 0% 100%
When the percent of charge and the Amp Hour (AH) rating of your battery
is known, you can calculate the approximate time needed to bring your
battery to a full charge.
To convert Reserve Capacity to Amp Hours, divide Reserve Capacity by 2,
and add 16:
Example:
Amp Hour Rating = Reserve Capacity + 16
2
NOTE: The Reserve Capacity can be obtained from the battery specica-
tion sheet or the owner’s manual.
To calculate the time needed for a charge:
Find the percent of charge needed (a battery at 50 percent charge that 1.
will be charged to 100 percent needs another 50 percent (.5)).
Multiply the Amp Hour Rating by the charge needed (.5) and divide by 2.
the charger setting (5 amps).
Multiply the results by 1.25 and you will have the total time needed, in 3.
hours, to bring the battery to a full charge.
Add an additional hour for a deep-cycle battery.4.
Example:
Amp Hour Rating x % of charge needed x 1.25 = hours of charge
Charger Setting
100 (AH Rating) x .50 (charge needed) x 1.25 = 12.5 hours
5 (Charger Setting)
100 x .50 x 1.25 = 12.5
5
A 100-Ampere Hour Battery must charge for 12 ½ hours when using the
above example.