The charging problem of the rechargeable battery has always been the focus of attention, and the correct charging method ensures the battery life. Rechargeable batteries recommend a variety of charging methods, different charging methods on the charger line has different requirements, naturally affect the cost.
Memory effect is a natural enemy of rechargeable batteries, is generally considered to be caused by long-term incorrect charging, it can make the battery prematurely. Memory effect can make the battery can not be effective charging, there is a full charge, one with the end of the phenomenon. The way to prevent the memory effect of the battery is to ensure that the battery "fully light" principle, that is, the best charge before the battery charge the amount of light, charge to a sufficient time. Nickel-cadmium batteries are prone to memory effects, so the charge to pay special attention to nickel-metal hydride batteries in theory there is no memory effect, but it is best to follow the "full light" principle, which is a lot of charger to provide additional features of the discharge The For the memory capacity due to memory capacity decline in the battery, we can once again by a one-time re-release method of repeated several times, most of the batteries can be repaired. For some shelved for a long time, the loss of the battery can try to hit with a large current shock method.
Battery charge time and charge current relationship for the battery capacity divided by the charge current to get the charging time, taking into account the loss of the charging process, so the calculated charging time multiplied by 1.2 constant.
For nickel-cadmium and nickel-metal hydride batteries the most commonly used simple charging method is the use of 10% C constant current charge, also known as "slow charge", that is, according to the current capacity of 10% of the value of the charge current, such as a nominal capacity of 500mAH Of the battery, it is recommended that the charging current of 50MA; another example of a nominal capacity of 1300mAH battery, it is recommended to charge current of 130MA. In this current continuous charging 12-15 hours can be seen as full. Although the proposed use of constant current charging but the requirements are not strict, the current allows a greater fluctuation, so in accordance with this method of making the charger structure is very simple, generally only need a 220V mains into a suitable low-voltage transformer for rectification Diodes, resistors for current limiting, and some light-emitting devices such as light-emitting devices, the cost is very low, the market most of the conventional conventional charger are used in this way, but the shape of different Bale. "Slow charge" Although relatively simple, but charge a power to wait more than ten hours, it is some impatient. Battery manufacturers also allow users to use 30% C current when the battery charge 4-5 hours, called "fast charge", but not recommended, theoretically the battery has a slight damage. So most of the conventional charger has "fast charge" and "slow charge" two files, and recommends that users use the "slow charge."
In many cases the user needs to charge the battery quickly, efficiently, and safely, and fast charging requires a larger current. The battery in the high current charging process will be polarized effect, so that the battery heat, and when the high current rechargeable battery is full, if not stopped in time, the battery will quickly heat, serious can lead to battery burn and explosion. So the requirements of fast charger with full self-stop function, but also to solve the polarization effect, so efficient and safe charging. Early fast charger with a simple timing charge, but such a charger targeted, charging effect is not satisfactory. Modern charger with a dedicated charge control IC to the high-frequency pulsating current to the battery charge to solve the polarization effect, through the detection of battery-ΔV accurately determine whether the battery is full, and provide protection measures such as temperature protection and discharge and other additional features. However, this charger structure is more complex, the cost is relatively high, generally used for mobile phones, walkie-talkie and other high-end communications equipment and electrical appliances.
Now on the market a lot of rechargeable battery models, only 5 batteries, for example, the capacity of 500MAH, 600MAH, 700MAH, 850MHA, 1200MAH, 1300MAH and so on. From the above 10% C "slow charge" principle we can understand that different capacity batteries need different charging current, the market some general-purpose charger for the early 500MAH and 600MAH battery design, charging current between 60-70mA, If you want to charge a larger capacity battery takes longer. The specific time can first use a multimeter to measure the actual charge current, and then divided by the battery capacity by the charge current multiplied by the coefficient of 1.2 to get charging time. For more than 1000mAH rechargeable nickel-metal hydride batteries can try to use ordinary charger fast charge, because this file current is large, with a multimeter to measure the actual charging current, if the value close to the charge of nickel-metal hydride batteries require 10% C charging current is just Crooked upright.