On the 6 volt setting, this is a manual
battery charger, and needs to be
disconnected from a battery when the
battery is fully charged. If this is not
done, the battery will overcharge,
resulting in possible battery damage.
A large automotive battery (65 amp
hours or 100 minutes of reserve
capacity) that is completely
discharged (lights will not come on at
all) should never take longer than 8
hours to charge on the 12 volt, 15
amp setting. Batteries with a partial
charge will take even less time to
charge. If the meter shows that the
battery is drawing amperage (from 7
to 15 amps) and after charging for up
to eight hours, the battery still isn’t
fully charged, have the battery
professionally tested or replaced. If
the meter shows zero amps and the
battery is still discharged, then
preactivation of the battery may be
required (see the paragraph entitled
"Preactivation of a Discharged
Battery" in the OPERATING
INSTRUCTIONS section).
The following instructions will allow
you to determine how long it will take
to bring a specific battery to full
charge. If the charger is so equipped,
a green light on the charger will
indicate the battery has become
fully charged.
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 use the formula in step 3 for
the charging rate capabilities of
your charger.
3. Use the battery rating, the charge
level of the battery, and the amp
setting to be used on the charger, in
the formula provided below.
Note: If the battery is rated in
RESERVE CAPACITY, use the
following formula to convert
reserve capacity to amp-hours.
8
Amp Hour
Rating of
Battery
Percent
of Charge
NEEDED
X
Amp Setting Selected
On Charger
X
1.25
=
Hours
to
Charge
EXAMPLE:
Battery's Present State of Charge: 25%
Percent of Charge NEEDED: 100% – 25% = 75%
Expressed as a Decimal: = .75
Amp setting on Charger: 10
Amp-Hour Rating of Battery: 60
60 X .75
10
X 1.25 = Hours to Reach Full Charge
45
10
X 1.25 = Hours to Reach Full Charge
X 1.25 = 5.625 Hours to Reach Full Charge
(5 Hours, 38 Min.)
4.5
Reserve Capacity
2
+
15.5
=
Amp-Hour Rating
TIME TO CHARGE
