Schumacher Electric SE-4022 Owner's Manual page 17

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 = 3.125 hours
20 (Charger Setting)
100 x .50 x 1.25 = 3.125
20
You would need to charge your 100-Ampere Hour Battery for a little more than
3 hours at the 20-Amp charge rate using the above example.
The Chart Method
Use the following table to more accurately determine the time it will take to
bring a battery to full charge. First, identify where your battery fits into the
chart.
NR means that the charger setting is NOT RECOMMENDED.
Find your battery's rating on the chart below, and note the charge time given
for each charger setting. The times given are for batteries with a 50% charge
prior to recharging. Add more time for severely discharged batteries.
13
• •