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MAXIMIZING THE CYCLE LIFE OF NICKEL CADMIUM BATTERIES

Maximizing the Cycle Life of Nickel Cadmium Batteries: Effective Maintenance Tips

Maximizing the Cycle Life of Nickel Cadmium Batteries: Effective Maintenance Tips

Introduction

Nickel Cadmium (Ni-Cd) batteries have long been used in various applications due to their durability and reliable ability to deliver consistent reliable power. However, like all batteries, they require preventive maintenance to ensure designed life. In this blog post, we will explore effective strategies to keep your Ni-Cd batteries healthy and optimise their lifespan.

Use the Correct Charger

The charging process plays a vital role in maintaining the health of Ni-Cd batteries. Invest in a quality charger specifically designed for Ni-Cd batteries. Such chargers provide a controlled charging voltages (Boost & Float) and current and terminate the charging process automatically when the battery bank is fully charged.

Charging

Battery can be charged by constant current and constant voltage methods. In normal operation, constant voltage method is applied.

 

While during the commissioning stage, constant current charging method is applied.

 

Special attention needs to provided for batteries connected as parallel strings . As current carried by each string would depend on the resistance of each string.

 

During regular usage, the charging method and parameters are to be determined by system requirements. A lower charging current can be applied for a proportionally longer time. Normally lower charging currents demonstrate better charge acceptability for batteries, but on the other hand, charging would need longer time.

 

Consistent Discharge and Usage

Ni-Cd batteries perform best when they are regularly discharged and used. Follow these practices to maintain a healthy battery:

a. Cyclic Operation: Ni-Cd batteries benefit from regular full discharges followed by full recharges. This process ensures the battery operates at its full capacity. However, we need to consider the Depth of Discharge (DOD) and the number of cycles to determine the life cycle of the batteries. Typical such application is Solar application where batteries are charged during say time and discharged during night.

b Float application: This is a typical battery back up application, where load is supplied by charger and batteries are used only when power / charger fails.

Regularly discharge your Ni-Cd battery to prevent it from sitting idle for extended periods. It is observed that during such float applications, the batteries may demonstrate reduced capacity.

Temperature Considerations

Operating Temperature has a impact on the cycle life of Ni-Cd batteries. Follow these temperature-related guidelines to ensure the health of your batteries.

 

Optimal Storage Temperature

filled and charged battery can be stored for a maximum period of six months, from the date of last charge. Filled and discharged batteries can be stored for one year. Do not store other material on top of the battery. Store the batteries in an enclosed room (1030˚C) and having sufficient ventilation. Cover the battery with a sheet of plastic or similar protective cover to keep out water and shield against direct sunlight.

After removing from storage, the battery should be deep discharged to an average cell voltage of 1.0 V by discharging at 0.2 C5 Amps, followed by deep discharge at 0.1 C5 Amps until all cell voltages fall below 0.6 Volts. Minimum 12 hours of time gap shall be given before starting to charge the cells.

However, a dry and discharged battery can be stored for prolonged periods.

Operating Temperature:

The battery will give the best performance and maximum service life when working at a

temperature between 10 and 30˚C. Freezing will not cause damage to the battery. With

adequate electrolyte specific gravity adjusted; the battery will perform properly up to – 40˚C.

 

Performance of nickel cadmium battery would be much better at elevated temperatures as compared to lead acid type batteries. All internal cell parts are nickel plated and can sustain the high temperatures up to 50˚C. The result of sustained high temperature would be quicker electrochemical reaction (high float current, poor internal gas recombination), leading to more water loss, necessitating water topping up, to maintain electrolyte level. If timely topping up of water is carried out, battery will continue to meet the requirements. However, if battery is operated continuously at higher temperatures, the overall life of battery would get reduced, when compared to it’s operation between recommended 10 to 30˚C.

 

Regular Maintenance Checks

Performing routine maintenance checks can help identify potential issues before they escalate. Consider the following steps:

a. Inspect for Corrosion: Check the battery terminals regularly for any signs of corrosion. If you notice corrosion, gently clean the terminals using a soft cloth and a mild cleaning agent.

b. Tighten Connections: Ensure that all connections between the battery and the device or charger are secure. Loose connections can lead to poor performance or damage to the battery.

c. Monitor Capacity: Periodically test the capacity of your Ni-Cd batteries using a battery analyser or suitable testing equipment. This can help you identify any decrease in capacity and take appropriate action.

d. Charger Discharge Test: The Charge/ discharge test of the Batteries using a load bank once in an year will help support to keep the batteries in good health and long life. Ensure to get the service from an experienced firm using high quality test equipment to obtain better service and maintenance.

Electrolyte Replacement

In most stationery battery applications, the electrolyte will retain its effectiveness for the life of the battery. However, under special battery service conditions, such, as high temperature and / or frequent cycling, potassium carbonate build up in the electrolyte may reach a level that will influence the battery performance. If the potassium carbonate reaches a level of 75 grams/ litre, is said to be carbonized, and the battery performance can be restored to a great extent by replacing the electrolyte.

The type of electrolyte to be used for replacement is given below.

CELL TYPE

ELECTROLYTE TYPE

FOR FIRST FILLING

ELECTROLYTE TYPE

FOR

REPLACEMENT

ELECTROLYTE TYPE FOR

COMMISSIONING

IF SUPPLIED DRY

Standard

B22, Density 1.20

B5, Density 1.19

B22, Density 1.20

Special Application

(Solar)

B30, Density 1.28

B12, Density 1.25

B30, Density 1.28

 

a.     Preparation of Electrolyte

1000 cc Type B electrolyte contains the following quantities of potassium hydroxide, lithium hydroxide and DM/DI water.

 

ELECTROLYTE TYPE FOR

REPLACEMENT

POTASSIUM

HYDROXIDE

(8889%)

LITHIUM

HYDROXIDE

(55%)

DM/DI WATER

B5, Density 1.19

276 gms

9 gms

910 cc

B12, Density 1.25

363 gms

22 gms

870 cc

 

Use this data as proportions for preparing the electrolyte for the battery in suitable batch

quantities depending on the size of the vessels available for electrolyte preparation.

 

b.    Discharge

Before emptying the electrolyte, discharge the battery to a voltage corresponding to about 0.6 volt/cell with current not higher than of 0.2C5 rate. The plates shall never be exposed to open atmosphere in charged condition.

 

c.    Emptying

Open the vents and place the battery inverted to drain the cells. Let the cells drain for about 5 minutes. Do not shake the cells. Beware of electrolyte splashes. Do not rinse with water, as this may cause trouble in obtaining correct electrolyte density after filling. Never let cells remain empty if they are not entirely discharged as this can cause permanent damage. It is not advisable to pour the used electrolyte into the sink. Follow norms for chemical waste disposal, which are valid in your area.

 

d.    Filling

Immediately after emptying, fill the cells according to the instructions for the electrolyte filling.

e.    Charge

Charge the battery according to the instructions for first charging. A generous charge is important for the restoration of the battery performance.

 

f.      Disposal of Used Batteries

Nickel cadmium batteries must not be discarded as harmless waste and should be treated carefully in accordance with local and national regulations. Contact HBL for disposal and recycling assistance. More than 99% of battery metals can be recycled.

 

g.    Spillage / Leakage of Electrolyte

Please refer our MSDS which gives necessary spillage management instructions.

Here are some additional maintenance tips for NiCd Batteries

  • Inspect the battery regularly for signs of damage. If the battery is leaking, cracked, or swollen, it should be replaced immediately.
  • Clean the battery terminals with a wire brush and a mild solution of baking soda and water. This will help to prevent corrosion and improve the battery’s performance.
  • Keep the battery terminals free of dirt and debris. This will help to prevent arcing and sparking, which can damage the battery.

By following these maintenance tips, you can help to extend the lifespan of your NiCd batteries and keep them in good working condition.

Conclusion

By following these maintenance tips one can optimise the cycle life of your Nickel Cadmium batteries and ensure their optimal performance. Remember to charge them properly, consistently discharge and use them, consider temperature conditions, and perform regular maintenance checks. By taking these simple steps, you can enjoy the full potential and longevity of your Ni-Cd batteries in various applications.

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