Schumacher 7000A Battery Charger User Manual


 
14
BATTERY PERCENT AND CHARGE TIME
This charger adjusts the charging time
in order to charge the battery com-
pletely, efficiently and safely. The
microprocessor automatically makes
the necessary decisions. However, this
section includes guidelines that can be
used to estimate charging times.
The duration of the charging process
depends 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 10). 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
provides charge rates of 2A and 20A.
The 70A rate is for engine start only.
The 2A rate is for charging smaller
batteries such as those used for
motorcycles and garden tractors.
Such batteries should not be charged
using the 20A rate. The 20A rate is
for charging larger batteries. The
7000A charges at the selected
charge rate and eventually reduces
the charge rate in a controlled man-
ner. After the charging process has
started, the digital display can be
used to determine charging progress
by selecting the BATTERY % 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 battery
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.