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Lead Acid Batteries Installation Operating Maintenance Instructions

Before starting the batteries installation begins, inspect for signs of damage or missing components. Store the battery in a dry, clean and preferably cool and frost-free location. Do not expose the cells to direct sunlight as damage to the container and cover may occur. As the batteries are supplied charged, storage time is limited. In order to easily charge the batteries after prolonged storage, it is advised not to store it more than:

  • 3 months at 20°C
  • 2 months at 30°C
  • 1 month at 40°C

A refreshing charge shall be performed after this time. Failure to observe these conditions may result in greatly reduced
capacity and service life. The refreshing charge shall be carried out according to the Commissioning Charge instructions


Alternatively, cells can be float charged at the recommended float voltage during storage. If the batteries are supplied moist charged, the storage time shall not exceed 2 years. For filling follow special instructions on filling and commissioning of moist charged batteries.

The electrical protective measures, the accommodation and ventilation of the battery installation must be in accordance with the applicable rules and regulations (Specifically EN 50272-2 and IEC 62485-2 apply).

Lead Acid Batteries Installation Method

The battery should be installed in a clean, dry area. Avoid placing the battery in a warm place or in direct sunlight. The layout of the charging room must allow easy access to the batteries. Approved battery racks are recommended for proper installation. Place the cells on the rack and arrange the positive and the negative terminals for connection according to the wiring diagram. Battery cells are usually installed in series.

Cells in parallel strings Vented cells may be connected in parallel to give higher current capability. In the case of parallel connected strings use batteries of the same capacity, design and age only with a maximum of 4 parallel strings. The resistance of the cables in each string must be the same, e.g. same cross-section, same length. Connect the battery strings in parallel at the end terminals.

Check that all contact surfaces are clean. If required, clean with a brass brush. Tighten the terminal screws, taking care to use the correct torque loading. To avoid damage to the plastic materials, do not use grease. Fit the covers supplied for
protection against inadvertent contact. Make sure that all caps are closed.

Torque loading for terminal screws:

Torque loadings for terminal screws
Carefully follow the polarity sequence to avoid short circuiting cell groups. A loose connector can make adjusting the charger difficult, create erratic performance and possible damage to the battery and/or even personal injury. Finally, with the charger switched off, the battery fuses removed and the load disconnected, connect the battery to the D.C. power supply.

Ensure that the polarity is correct – positive terminal of the battery to the positive terminal of the charger. Switch on the charger and charge according to the commissioning charge paragraph below. The first charge must be monitored to ensure that the limits are not exceeded and that no unacceptable temperatures occur. The electrolyte level on delivery can vary.
The final electrolyte level will be achieved after the commissioning charge. Small quantities (up to 3 mm) can be topped up with distilled water.

Commissioning Charge

When commissioning a new battery supplied filled and charged (first charge), follow procedure a, b, or c. Procedures a or b are recommended.

a) IU method (boost charge):

At a raised voltage of 2.33 – 2.40V/cell. The charging time will be 12 to 36 hours depending on the initial charge
conditions. The current must be limited to 4 x I10.

b) I method (boost charge):

With a constant current of 2.5-5 A/100 Ah with a final charging voltage of 2.50-2.75 V/cell. The charging must be monitored.
The charging time can be 6 to 24 hours. If the maximum temperature of +45°C is exceeded, charging must be terminated, continued at a reduced current, or temporarily switched to float charging. Boost charging must be immediately switched off or switched to float charging when the fully charged state is reached.

c) Float charge:

With the recommended float voltage according to table 5. Full capacity will be obtained after a longer period of 4 to 6 weeks depending on the state of charge. The fully charged condition has been achieved when, for a period of 2 hours, the cell voltages do not continue to increase and the charging current does not continue to decrease. The nominal specific gravity shall be achieved at the end of charge (tolerance: ± 0.01). For minimum end of charge voltages using the constant current characteristic
see below end of charge voltages table:

end of charge voltages

For the commissioning charge of moist charged cells, please refer to the specific moist charged instructions.

Capacity Testing of Batteries

Capacity tests are to be carried out in accordance with EN 60896-11. Check that the battery is fully charged. Before testing new batteries it must be ensured that a sufficient commissioning charge has been applied, the S.G. is relating to the nominal value (± 0.01 kg/l) and the battery is fully charged. Lower S.G. results in lower capacity.


After a discharge the battery can be recharged at the operating voltage (float charge voltage). To reduce the charging time the recharging can be carried out with the boost charge voltage of 2.33 to 2.40 V/c. The recharging times depend on the charging procedure and on the charging current available.

Generally 10 to 20 hours duration can be expected at charging currents between 5 A and 40 A per 100 Ah nominal capacity.
Recharge 1.2 times the discharged capacity. During recharging up to 2.40 V/cell the effective value of the A.C. ripple current can reach a temporary maximum 10 A per 100 Ah nominal capacity.

Equalizing Charge

After a deep discharge or after inadequate recharging, an equalizing charge is necessary. This can be carried out as follows:
a) at constant boost charge voltage of 2.33 – 2.40 V/cell for a maximum of 72 hours.
b) with I charge method according to the commissioning charge paragraph above, clause b).

If the maximum temperature of 45°C is exceeded, charging must be terminated or continued at a reduced current or temporarily switched to float charging. The end of equalizing charge is reached when the S.G. of the electrolyte and the cell voltages have not risen for a period of 2 hours. Because the permissible system voltage level may be exceeded when charging at increased voltages, suitable measures should be taken to protect the load circuits, e.g. charging «off line».

Maintenance Checks for Batteries

Water topping: Top up the electrolyte level to the nominal level, but without exceeding the « Max » mark. Only demineralised or distilled water (purity grade: max. conductivity 10 μS/cm) shall be used. After topping-up an equalizing charge can be applied to reduce the time for homogenization of the electrolyte density.

Cleaning: Keep containers and lids dry and free from dust. Cleaning must be undertaken with a damp cotton cloth without man-made fibers.

WARNING – Do NOT use any type of oil, solvent, detergent, petroleum-based solvent or ammonia solution to clean the battery containers or lids. These materials will cause permanent damage to the battery container and lid and will invalidate the warranty. If the battery, cell, lid or container is damp with or shows signs of spilled electrolyte, wipe with a cloth dampened with a solution of sodium bicarbonate and cold water, mixed in the proportions of 1.0 lb/1.0 gal (0.5 kg/5.0 liter) of water. Follow this by wiping with a cloth dampened in clear water. Avoid static discharges generated during cleaning.

Plugs: Leak-resistant plugs with a frit or flame arrestor plugs with a ceramic funnel must not be cleaned with water or positioned up side down. Should the frit be moistened with electrolyte, the plug must be replaced during regular maintenance. Standard plugs without frit can be cleaned with purified water if necessary. Dry them thoroughly before fitting them back onto the battery.

Readings – Log book

Every 6 months, check the total voltage at the battery terminals. Also check the voltage, S.G., and the temperature of pilot cells and record the room temperature. Once a year, in addition to the above, take readings of individual voltages and S.G. of the electrolyte. Measure the S.G. either before topping up water or after boost charge.

Keep a logbook in which the measured values can be noted as well as power cuts, discharge tests, equalizing charges, topping up dates, storage times and conditions, etc.

Discharging the Batteries

End of Discharge Voltage:

The battery must not be discharged more than the capacity specified in the performance tables. Deeper discharges may damage the battery and shorten its operational life. As a general rule the end of discharge voltage shall be limited to the values listed below:

end voltages

Individual cell voltages may fall below UE by not more than 0.2 V/c. A low voltage disconnect is recommended to prevent deep discharge. Special attention should be given to small loads that are not automatically disconnected at the end of discharge

Discharged Cells:

Batteries must not be left in a discharged condition after supplying the load, but must be immediately returned to recharge mode. Failure to observe these conditions may result in greatly reduced service life and unreliability.

Safety precautions

Batteries give off explosive gasses. They are filled with dilute sulphuric acid which is very corrosive. When working with sulphuric acid, always wear protective clothing and glasses. Exposed metal parts of the battery always carry a voltage and are electrically live (risk of short circuits). Avoid electrostatic charge. The protective measures according to EN 50272-2 and IEC 62485-2 must be observed.


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