Schumacher SC-12000A - Manual (Page 13)

12
BATTERY PERCENT AND CHARGE TIME
This charger adjusts the charging time in
order to charge the battery completely,
efficiently and safely. The microproces-
sor automatically makes the necessary
decisions. However, this section includes
guidelines that can be used to estimate
charging times.
The duration of the charging process de-
pends on three factors:
1. Battery State – If a battery has only
been slightly discharged, it can be
charged in less than a few hours.
The same battery could take up to 10
hours if very weak. The battery state
can be estimated by using the built-in
tester (see page 12). The lower the
reading the longer charging will take.
2. Battery rating – A higher rated
battery will take longer to charge
than a lower rated battery under the
same conditions. A battery is rated in
ampere-hours (AH), reserve capacity
(RC) and cold cranking amps (CCA).
The lower the rating the quicker the
battery will be charged.
3. Charge rate – The charge rate is
measured in amps. This charger pro-
vides charge rates of 2A, 15A40A.
The 120A rate is for engine start only.
The 2A rate is for charging smaller
batteries such as those used for mo-
torcycles and garden tractors. Such
batteries should not be charged using
the REGULAR BATTERY setting.
The 15A40A rates are for charg-
ing larger batteries. In the REGULAR
BATTERY mode, the charger begins
at the 15A rate and increases the
charge rate if it is determined that
the battery can accept the 40A rate.
All charging modes will decrease the
charge rate as the battery approaches
maximum charge.
After the charging process has started, the
digital display can be used to determine
charging progress by selecting the BAT-
TERY % mode.
There are some important facts to keep in
mind when charging a battery.
• When the display indicates 77%
charged, the battery has been charged
enough to start most vehicles and has
already been charged as much as by
many other battery chargers.
• When the display indicates 85%
charged, the battery has already been
charged at least as much as by most
other battery chargers.
• The battery % shown in tester mode
is an estimate based on the bat-
tery voltage and the Battery Council
International scale. The battery %
shown in charger mode is an estimate
of the relative charge in the battery
compared to the charge it should have
if the charging process is allowed to
complete.
• The battery % shown in tester mode
can be used to estimate the relative
charge time. The lower the % shown,
the longer the charge time for a given
battery.
• The battery % shown in charger mode
is an indication of the relative progress
of the charging process. The higher
the battery % displayed, the less
charge time remains.
• The more a battery is discharged,
the faster it absorbs charge from a
charger. That means that the battery
% increases faster at the beginning
of the charging process than at the
end. In other words, it takes longer
for the battery to absorb the last few
percent of charge than the first several
percent.