section, etc.), in order to avoid overloading of the electric
cables and contacts, unacceptable gassing and the escape of
electrolyte from the cells. In the gassing stage, the current
limits given in EN 62485-3 must not be exceeded.
If the charger was not purchased together with the battery
it is best to have the charger’s, cables and plugs suitability
checked by the manufacturer’s service department. When
charging, proper provision must be made for venting of the
charging gases.
Truck doors, battery container lids and covers of battery com-
partments must be opened or removed.
During the charge in the truck, those from the manufacturers’
specified vents have to be opened.
In all cases, the ventilation must comply with EN 62485-3
standard. The vent plugs should remain on the cells and
be kept closed. With the charger switched off, connect the
battery, ensuring that the polarity is correct (positive to
positive, negative to negative).
Then switch on the charger. During the charging process,
the temperature of the electrolyte rises by about 10°C, so
charging should only begin if the electrolyte temperature is
below 45°C.
The electrolyte temperature of batteries should be at least
+10°C before charging otherwise a full charge would not be
achieved. A charge is finished when the specific gravity of the
electrolyte and the battery voltage have remained constant
for two hours. EnerSys chargers automatically indicate end
of charge.
Batteries fitted with electrolyte circulation system (optional):
in case a pump fault is indicated, check that the piping system
is connected and examine the piping circuit for leaks or
defects (see point 3.4).
The air pipe should never be removed during charge.
2.3 Equalizing charge
Equalizing charges are used to safeguard the life of the
battery and to maintain its capacity. They are necessary after
deep discharges, repeated incomplete recharges and charges
to an IU characteristic curve. Equalizing charges are carried
out following normal charging. The charging current must
not exceed 5 A/100 Ah of rated capacity (end of charge - see
point 2.2). Watch the temperature!
2.4 Temperature
An electrolyte temperature of 30°C is specified as the rated
temperature. Higher temperatures shorten the life of the
battery; lower temperatures reduce the capacity available.
55°C is the upper temperature limit and is not acceptable as
an operating temperature.
2.5 Electrolyte
The rated specific gravity (S. G.) of the electrolyte is related to
a temperature of 30°C and the nominal electrolyte level in the
cell in fully charged condition.
Higher temperatures reduce the specified gravity of the
electrolyte, lower temperatures increase it. The temperature
correction factor is -0.0007 kg/l per °C, e.g. an electrolyte
specific gravity of 1.31 kg/l at 45°C corresponds to an S.G. of
1.32 kg/l at 30°C. The electrolyte must conform to the purity
regulations in IEC 62877-2: 2016.
3. Maintenance
3.1 Daily
Charge the battery after every discharge.
The electrolyte level must not fall below the top of the
separator or the electrolyte ”min” level mark.
NO WATERING IN THE FIRST 10 CYCLES.
3.1.1 Filling level sensors
In the case of batteries with filling level sensors, the LED
should be observed daily.
LED green
level OK
LED red blinking
level too low
Do not top up the cells even when electrolyte level sensor
shows a red blinking LED during first 10 cycles.
Check the electrolyte level by the position of the float
indi
cator of the water filling plug and top-up with
demineralized water at the end of the charge. Since the
display always refers to a selected reference cell, please
also pay attention to the additional instructions under
point 3.3.
3.2 Weekly
Visual inspection after recharging for signs of dirt and
mechanical damage to all component parts of the battery, pay
particular attention to the battery charging plugs and cables.
By special applications with charge with a IU characteristic
curve an equalizing charge must be carried out (see point 2.3).
3.3 Monthly
At the end of the charge, the voltages of all cells should
be measured with the charger switched on, and recorded.
After charging has been completed, the electrolyte density,
electrolyte temperature as well as the filling level (when
filling level sensors are used) of all cells are to be measured
and recorded. If significant changes from earlier measu-
rements or differences between the cells are found further
testing and maintenance by the service department should be
requested. This should be done following a complete charge
and minimum of 2 hours rest time.
Measure and record:
• Total voltage
• Voltage per cell
• If the voltage readings are irregular, also check the S.G. of
each cell
3.4 Annually
In accordance with EN 1175-1 at least once per year, an
electrical specialist must check the insulation resistance of the
truck and the battery. The tests on the insulation resistance of
the battery must be conducted in accordance with EN 1987-1.
The insulation resistance of the battery thus determined
must not be below a value of 50 Ohm per Volt of nominal
voltage, in compliance with EN 62485-3. For batteries up to
20 V nominal voltage, the minimum value is 1,000 Ohm.
Batteries fitted with electrolyte circulation system: the
filter of the air pump has to be checked at least during the
annual maintenance and eventually to be cleaned or
replaced. Depending on the environment, a higher frequency
for filter check than once per year may be necessary. Earlier
replacement of the filter is necessary if for undefined reasons
(no leaks in the air pipes) the defect signal of the air mixing
system on the charger or on the battery (on DC air pump or
remote signal) is illuminated. During the annual maintenance,
check the correct operation of the air pump.
4. Care of the battery
The battery should always be kept clean and dry to prevent
tracking currents. Cleaning must be done in accordance with
the ZVEI code of practice “The Cleaning of Vehicle Traction
batteries”. Any liquid in the battery tray must be extracted
and disposed of in the prescribed manner. Damage to
the insulation of the tray should be repaired after
cleaning, to ensure that the insulation value complies
with EN 62485-3 and to prevent tray corrosion. If it is
necessary to remove cells, it is best to call in EnerSys service
department for this.
Never use (apply) mineral grease on the battery, the sealing
material of the terminal is incompatible and it can be per-
manently damaged. If it‘s necessary, use (apply) the silicone
grease with TPFE.
5. Storage
If batteries are taken out of service for a lengthy period,
they should be stored in the fully charged condition in a dry,
frost-free room. To ensure the battery is always ready for use
a choice of charging methods can be made:
1. a monthly equalizing charge as in point 2.3, or
2. float charging at a charging voltage of 2.29 V x the number
of cells.
The storage time should be taken into account when conside-
ring the life of the battery.
6. Malfunctions
If malfunctions are found on the battery or the charger,
EnerSys service should be called in immediately. The
measurements taken in point 3.3 will facilitate fault finding
and their elimination.
A service contract with us will make it easier to detect and
correct faults in good time.
