Yale MPB040E Manual page 59

2200 YRM 1007
If the charger begins the charge cycle, but stops be-
fore it is complete and an error light comes on, this
usually indicates a problem with the batteries.
NOTE: The charger has an electronic safety timer
that will detect if the batteries are not responding to
the charge within the prescribed time period. The
charger will shut itself down if it determines there is a
problem with the batteries.
1. If the charger is unable to raise the battery volt-
age above 1.7 volts/cell (20.4 volts total) within
one minute after start up, it will stop charging and
a constant red LED will light up.
2. If the charger is unable to raise the battery volt-
age above 2.05 volts/cell (24.6 volts total) within
one hour after start up, it will stop charging and a
constant red LED will light up.
3. If the charger is unable to raise the battery volt-
age above 2.42 volts/cell (29.0 volts total) within
10 hours after start up, it will stop charging and a
constant red LED will light up.
4. If at any time during the charge cycle the trans-
former overheats, the charger will stop, the yellow
LED will stay on, and the red LED will flash. This
may appear to be a charger issues, but it is
caused by the batteries. If the battery voltage
does not rise as it should, the charger output cur-
rent will increase, which raises the transformer
temperature. Eventually, it will become too hot,
causing the charger to shut down to protect itself.
The charger will restart itself and begin charging
again after the transformer has cooled down, but
the same situation may occur again. If this hap-
pens within one hour after start up, the one hour
timer will expire and shut the charger down as de-
scribed in item 2 above.
All of the cases above are indicative of a set of batter-
ies that are not responding properly to the charger
due to one or more weak or failing cells.
When any one of these situations occur, it is best to
unplug the charger and inspect the batteries for one
or more bad cells. This can be done with a load tester
or a specific gravity test. If the variation between the
highest and lowest specific gravity reading between
the three cells in any one battery is 0.050 (50 gravity
points) or more, there is a reason to suspect a weak
or failing cell.
If a battery has a bad cell, it must be replaced. To im-
prove battery life, and to get the maximum amount of
run time out of each charge cycle, it is best to replace
all four batteries at the same time.
If all the above steps have been taken and the
charger still does not function properly, the charger
should be replaced.
Battery Charger (Moran
®
)
35