Charging Time Instructions
Manual battery chargers need to be disconnected from a battery when the battery has reached 100% of charge or
sooner. If this is not done, the battery will overcharge, resulting in possible battery damage.
The following instructions or the associated Length of Charge Time Charts (60 amps down to 2 amps, one for each
charging range) will allow you to determine how long it will take to bring a specific battery to full charge.
CAUTION: Batteries that have 25% charge or less can easily freeze and should be charged at once, but do not
charge a battery that is already frozen.
1. Determine the present level of charge in the battery with a hydrometer or electronic percent-of-charge
tester.
2. Determine the size of the battery in Amp-Hours or Reserve Capacity. If these ratings are not printed on the
battery, contact your local battery dealer for this information. These are the only ratings that can be used
to determine length of charging time. Then either use the formula in step 3 or use Table 2 plus Table 3
through Table 9 for the charging rate capabilities of this charger.
3. Use the battery rating, the charge level of the battery, and the amp setting to be used on the charger (see
Table 2) in the formula provided below.
Amp Hour
X
Rating of
Battery
Amp Setting Selected
On Charger
Example:
Battery's Present State of Charge: 25%
Percent of Charge Needed: 100% - 25% = 75% Decimal = .75
Amp Setting on Charger: 10
Amp-Hour Rating of Battery: 60
60 X .75
X 1.25 = Hours to Reach Full Charge
10
45
X 1.25 = Hours to Reach Full Charge
10
4.5
X 1.25 = Hours to Reach Full Charge
Note: If the battery is rated in Reserve Capacity, use the following formula to convert reserve capacity to amp-hours.
Reserve Capacity
2
Percent
of Charge
=
X
1.25
NEEDED
+
=
15.5
Amp-Hour Rating
Hours
to
Charge
17