Sears 200.71201 - Manual (Page 9)

Calculating charge time
The Hydrometer or Electronic Method
To find the time needed to fully charge your battery,
determine the battery's charge level with a hydrometer
or electronic Percent-of-Charge Tester. The following
table will help you convert hydrometer readings to
percent of charge values.
SPECIFIC PERCENT PERCENT OF
GRAVITY OF CHARGE CHARGE NEEDED
1.265 100% 0%
1.225 75% 25%
1.155 25% 75%
1.120 0% 100%
When you know the percent of charge and the Amp
Hour (AH) rating of your battery, 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:
Amp Hours = Reserve Capacity +16
2
To calculate time needed for a charge:
• Find the percent of charge needed. (A battery at
50 percent charge that will be charged to 100
percent needs another 50 percent (.50),
• Multiply the Amp Hour rating by the charge
needed (.50) and divide by the charger rate
(1,5 amps),
• Multiply the result by 1,25 and you’ll have the
approximate time needed, in hours, to bring the
battery to full charge.
• Add one additional hour for a deep-cycle battery.
Example:
Amp Hour Rating x charge needed x 1.25 = hours
Charger Setting of
charge
20 fAH Ratingf x .50 (charge needed! x 1,25 = 8.33
1.5 (Charger Setting) hours
20 X .5 = 6.66 x 1.25 = 8.33
1.5
You would need to charge your 20-Ampere Hour Bat­
tery for approximately 8 hours at the 1.5-Amp charge
rate using the above example.