Charger Reference
| Type: |
Switch Mode Power Supply (SMPS) |
| Input Voltage: |
100-240VAC |
| Output Current: |
max. 650mA |
| Charging Time: |
4hrs for BAJ1/BAJ2 battery pack |
| Indicator Lights: |
Green: ON - charger is connected to mains power |
| |
Yellow: ON - battery is charging |
| |
OFF - battery is fully charged |
Charge Profile
| The following figure illustrates the charge for a very empty
battery, showing the three distinct stages of a typical charge.
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- Constant Current at 650mA: If a battery is empty it will
accept current at a rate far higher than the charger can
safely supply. To prevent damage the charger will limit its
output to 650mA (approximately C/4). The battery is charged
at this rate until it reaches a voltage of 29.4V.
- Constant Voltage at 29.4V: If it were to continue charging
at 650mA the battery voltage would rise very quickly and damage
from overcharging would result. To avoid this the charger
continually reduces its current to maintain a constant voltage
of 29.4V for the remainder of the charge.
- Trickle Charge at 27.6V: Once the current drops below 50mA the
charge is essentially complete. The yellow light goes out to
indicate this, and the battery can be removed from the charger
and put into use. If the battery is left on the charger a very
small trickle current of around 20mA maintains the battery
voltage at a constant 27.6V. This keeps the battery ready for use
over an indefinite period, and improves the battery’s long term
cycle life by counteracting self-discharge.
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Testing the Charger
If you suspect that the charger is not functioning correctly
perform the following tests:
- Measure the voltage across the charger terminals with no
battery present. It should be 27.6V±1.4V.
- Short circuit the charger terminals with a 100ohm resistor
(this gives a charger current of roughly 300mA). The voltage
across the terminals should read as 29.4V±1.5V.
If the charger fails either of these tests it is faulty and should
be replaced.
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Testing the Battery
Unfortunately the capacity of any battery does diminish with use.
The following tests can help determine whether a battery has
reached the end of its useful life.
- Measure the voltage across the battery terminals. A full
battery will read above 24V, an empty one less than 20V.
Anything below 18V should be considered very empty and it
is very bad practice to allow batteries to drain so low.
A reading of 0V across the terminals indicates that the
battery has been shorted circuited and its internal safety
fuse has blown.
- Place the battery on the charger and wait for the yellow
light to go out. The voltage across the terminals should
measure around 26V immediately after being removed from
the charger. A voltage of less than 24V indicates that
the battery should be replaced.
- Connect the freshly charged battery to a lifter and lift a
load up and down once. The voltage should be above 25V,
anything else and the battery should be replaced.
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