Due to improvements in manufacturing, Ni-Cd batteries are now used in most portable electronic devices. Reasonable cost and high performance have made the presented type of batteries popular. Such devices are now widely used in tools, cameras, players, etc. In order for the battery to last a long time, you need to know how to charge Ni-Cd batteries. By adhering to the rules for operating such devices, you can significantly extend their service life.
Key Features
To understand how to charge Ni-Cd batteries, you need to familiarize yourself with the features of such devices. They were invented by W. Jungner back in 1899. However, their production was then too costly. Technology has improved. Today, easy-to-use and relatively inexpensive nickel-cadmium batteries are on sale.
The presented devices require fast charging and slow discharging. Moreover, the emptying of the battery capacity must be performed completely. Recharging is done by pulsed currents. These parameters should be adhered to throughout the life of the device. Knowing what current to charge the Ni-Cd battery, you can extend its service life by several years. At the same time, such batteries are operated even in the most difficult conditions. A feature of the presented batteries is the "memory effect". If you do not periodically discharge the battery completely, large crystals will form on the plates of its cells. They reduce battery capacity.
Benefits
To understand how to properly charge the Ni-Cd batteries of a screwdriver, camera, camera and other portable devices, you need to familiarize yourself with the technology of this process. It is simple and does not require special knowledge and skills from the user. Even after the battery has been stored for a long time, it can be quickly charged again. This is one of the advantages of the presented devices, which make them in demand.
Nickel-cadmium batteries have a high number of charge and discharge cycles. Depending on the manufacturer and operating conditions, this figure can reach more than 1 thousand cycles. The advantage of the Ni-Cd battery is its endurance and the ability to work under stressed conditions. Even when operating it in the cold, the equipment will work properly. Its capacity in such conditions does not change. At any state of charge, the battery can be stored for a long time. An important advantage of itsis low cost.
Flaws
One of the disadvantages of the presented devices is the fact that the user must definitely learn how to properly charge Ni-Cd batteries. The presented batteries, as mentioned above, have a “memory effect”. Therefore, the user should periodically take preventive measures to eliminate it.
The energy density of the presented batteries will be slightly lower than that of other types of autonomous power sources. In addition, in the manufacture of these devices, toxic materials that are unsafe for the environment and human he alth are used. Disposal of such substances requires additional costs. Therefore, the use of such batteries is restricted in some countries.
After a long period of storage, Ni-Cd batteries require a charge cycle. This is due to the high rate of self-discharge. This is also a design flaw. However, knowing how to properly charge Ni-Cd batteries and operate them correctly, you can provide your equipment with an autonomous power source for many years.
Varieties of chargers
In order to properly charge a nickel-cadmium type battery, you need to use special equipment. Most often it comes with a battery. If for some reason there is no charger, you can purchase it separately. On sale today are automatic and reverse impulse varieties. Using the first type of devices,the user does not need to know what voltage to charge Ni-Cd batteries. The process is carried out automatically. Up to 4 batteries can be charged or discharged at the same time.
Using a special switch, the device is set to discharge mode. In this case, the color indicator will glow yellow. When this procedure is completed, the device automatically switches to charging mode. The red indicator will light up. When the battery reaches the required capacity, the device will stop supplying current to the battery. In this case, the indicator will turn green. Reversible chargers belong to the group of professional equipment. They are capable of multiple charge and discharge cycles with varying duration.
Special and universal chargers
Many users are interested in the question of how to charge the battery of a Ni-Cd type screwdriver. In this case, a conventional device designed for finger batteries will not work. A special charger is most often supplied with a screwdriver. It should be used when servicing the battery. If there is no charger, you should purchase equipment for batteries of the type presented. In this case, it will be possible to charge only the battery of the screwdriver. If there are different types of batteries in operation, it is worth purchasing universal equipment. It will allow servicing autonomous energy sources for almost all devices (cameras, screwdrivers and even batteries). For example, it can charge iMAX B6 Ni-Cd batteries. This is a simple and useful household appliance.
Discharging a pressed battery
Extruded Ni-Cd batteries are characterized by a special design. How to charge and discharge the presented devices depends on their internal resistance. This indicator is influenced by some design features. For long-term operation of the equipment, disk-type batteries are used. They have flat electrodes of sufficient thickness. During discharging, their voltage slowly drops to 1.1 V. This can be verified by plotting the curve.
If the battery continues to discharge to 1 V, its discharge capacity will be 5-10% of the original value. If the current is increased to 0.2 C, the voltage is significantly reduced. This also applies to battery capacity. This is due to the impossibility of discharging the mass uniformly over the entire surface of the electrode. Therefore, today their thickness is reduced. At the same time, there are 4 electrodes in the design of the disk battery. In this case, they can be discharged with a current of 0.6 C.
Cylindrical batteries
Today, batteries with ceramic-metal electrodes are widely used. They have low resistance and provide high energy performance of the device. The voltage of a charged Ni-Cd battery of this type is held at 1.2 V until 90% of the specified capacity is lost. About 3% of it is lost during the subsequent discharge from 1.1 to 1 V. The presented type of batteries can be discharged with a current of 3-5 C.
Roll-type electrodes are installed in cylindrical batteries. They can be discharged with a current with higher rates, which is at the level of 7-10 C. The capacitance indicator will be maximum at a temperature of +20 ºС. As it increases, this value changes insignificantly. If the temperature drops to 0 ºС and below, the discharge capacity decreases in direct proportion to the increase in the discharge current. How to charge Ni-Cd batteries, the varieties of which are commercially available, must be considered in detail.
General charging rules
When charging a nickel-cadmium battery, it is extremely important to limit the excess current flowing to the electrodes. This is necessary due to the buildup inside the device during this process of pressure. When charging, oxygen will be released. This affects the current utilization factor, which will decrease. There are certain requirements that explain how to charge Ni-Cd batteries. Process parameters are taken into account by manufacturers of special equipment. Chargers in the course of their work report to the battery 160% of the nominal capacity value. The temperature interval throughout the entire process must remain within the range from 0 to +40 ºС.
Standard charge mode
Manufacturers must indicate in the instructions how much to charge a Ni-Cd battery and what current it should be done. Most often, the execution mode of this process is standard for most types of batteries. If the battery has a voltage of 1 V, it should be charged within 14-16 hours. In this case, the current shouldbe 0, 1 S.
In some cases, the characteristics of the process may differ slightly. This is influenced by the design features of the device, as well as the increased laying of the active mass. This is necessary to increase the capacity of the battery.
The user may also be interested in what current to charge the Ni-Cd battery. In this case, there are two options. In the first case, the current will be constant throughout the entire process. The second option allows you to charge the battery for a long time without the risk of damaging it. The scheme involves the use of a stepwise or smooth decrease in current. At the first stage, it will significantly exceed 0.1 C.
Fast charging
There are other ways that Ni-Cd batteries are accepted. How to charge a battery of this type in accelerated mode? There is a whole system here. Manufacturers increase the speed of this process through the release of special devices. They can be charged at high current rates. In this case, the device has a special control system. It prevents a strong overcharging of the battery. Either the battery itself or its charger can have such a system.
Cylindrical varieties of devices are charged with a constant type current, the value of which is 0.2 C. The process will last only 6-7 hours. In some cases, it is allowed to charge the battery with a current of 0.3 C for 3-4 hours. In this case, process control is essential. With accelerated execution of the procedure, the recharge indicator should beno more than 120-140% capacity. There are even batteries that can be fully charged in just 1 hour.
Stop charging
When learning how to charge Ni-Cd batteries, you need to consider completing the process. After the current stops flowing to the electrodes, the pressure inside the battery still continues to rise. This process is due to the oxidation of hydroxide ions on the electrodes.
For some time there is a gradual equation of the rate of oxygen evolution and absorption on both electrodes. This leads to a gradual decrease in pressure inside the accumulator. If the recharge was significant, this process will be slower.
Mode setting
To properly charge a Ni-Cd battery, you need to know the equipment setup rules (if provided by the manufacturer). The nominal capacity of the battery must have a charge current of up to 2 C. It is necessary to select the type of pulse. It can be Normal, Re-Flex or Flex. The sensitivity threshold (pressure drop) should be 7-10 mV. It is also called Delta Peak. It is better to set it at the minimum level. The pump current must be set in the range of 50-100 mAh. To be able to fully utilize the power of the battery, you need to charge with a large current. If its maximum power is required, the battery is charged with a small current in normal mode. By looking at how to charge Ni-Cd batteries, each user will be able to complete this process correctly.
