I have found that a friend made a lot of battery and charger, so that this feature article to share with you. Whether digital camera, or radio, Walkman, MP3 and so on, the battery power of all devices, battery performance is good or bad decision to use the equipment performance. The battery structure is different, different size, capacity, vary considerably, that is the same size battery, due to the different models, different manufacturers, capacity not the same.

Take our most popular AA size batteries (5 batteries), the early nickel-cadmium Dell vostro 1500 battery capacity is 500mAh, modern nickel-cadmium battery capacity is 850mAh, while the same size nickel-metal hydride batteries have greater capacity, at 1100mAh ~ 2100mAh between. MAh battery capacity is calculated, you can be understood as in how many mA (mA) current, discharge 1 hour. For example, 1000mAh means the battery can 1000mA discharge current of 1 hour and such a large capacity. Thus, if the load (with electrical) power consumption is 100mA, the battery can discharge 10 hours, if the load current is 200mA, the battery can be used 5 hours, and so on. Battery principle is a chemical reaction produces electricity, two kinds of metal materials under the influence of the electrolyte produce current, which we in secondary schools have learned in physics class too.

Different types of battery terminal voltage is not the same as dry-cell batteries 1.5V, silver oxide battery 1.55V, silver mercury battery 1.3V, nickel-cadmium batteries and nickel-metal hydride battery 1.2V, lead-acid battery 2V, disposable lithium batteries 3V, rechargeable lithium battery 3.6V. With the electrical supply voltage is different from the use of battery types and sessions are also different. For example, the early use of chewing gum Eva Walkman-type lead-acid batteries, the working voltage design 2V, new Sony Walkman gum use nickel-cadmium batteries, terminal voltage of 1.2V, a modern multi-use digital camera lithium battery, the working voltage of up to 7.6V, needed two series of secondary lithium battery-powered (though monomer, but inside the shell encapsulates the two rechargeable lithium batteries), and most modern radios were designed to be able to use dry batteries or Ni-Cd, Ni-MH batteries, from 2 ~ 4 cells in series power supply, power supply voltage can be changed within a certain range. The battery can no longer be a one-time charge, such as batteries, alkaline batteries, silver oxide batteries, silver and mercury battery, a lithium battery. After the exhaustion of their power can only be scrapped. Many people tried to charge these batteries, design a variety of chargers, writing a large number of articles,

I too, have made great efforts to this end, has done hundreds of times for various battery tests, the results of little effect, charging after the battery capacity of even half of the new can not be achieved, and then discharge again soon dried up! But today there are still many articles, make such a deceptive theory and charging products. With the development of technology, battery technology advances, although this progress compared to other electrical appliances to become too slow. Nickel-cadmium rechargeable batteries have a long history, and its relatively complete variety of specifications, but most of the cylinder-shaped, sizes, capacity different. This battery discharge performance than the dry well, resistance is relatively low, allowing large current discharge, but the memory strong, normal life at between 400 to 1,000 times. In recent years a large number of developing nickel-metal hydride batteries have greater capacity, lower resistance, more suitable for large current discharge, the memory feature much smaller than the nickel-cadmium life 1000 times more in charge and discharge, the price is not much expensive.

Therefore, to replace the nickel-cadmium nickel-metal hydride is an inevitable trend, is now rarely seen on sale of the nickel-cadmium batteries. Rechargeable lithium battery is the latest generation of advanced batteries, it has a terminal voltage, high-capacity maximum, ultra-low resistance, stable performance, long life characteristics (charge and discharge 1000 and above). But its price is relatively high, mainly used in advanced electrical appliances, such as laptop computers, mobile phones, handheld computers, digital cameras and so on. Memory characteristics of the battery is that, if you often let the battery discharge into the left half of the capacity to call it charge, then the course of time of its actual capacity would be reduced. There is no memory characteristic of the battery can be added at any time for its electricity, its capacity would not be any changes. At present, only lithium battery claimed there is no memory characteristic of the battery, but in fact any chemical batteries have a certain memory characteristics, if you often it is not fully discharged its case for additional power, then its capacity will be more to smaller, life will be shortened.

After several tests, I found that lithium batteries have memories of the same characteristics, but lighter than nickel-cadmium batteries a little. We are using the battery, the only correct way is to completely depleted battery to give it after charging, and using a reasonable charging method for its charge, see below. Secondary battery is fully charged terminal voltage difference, nickel cadmium and nickel-metal hydride nominal voltage is 1.2V, full of power between 1.3 ~ 1.5V in future, with the discharge quickly dropped to 1.2V, shorting electricity after the terminal voltage in the 1V! This is important, absolutely can not put a single cell voltage below 1V, or detrimental to battery life. Over the depth of discharge is often a one-time damage the Dell vostro 1700 battery completely, so that the internal short-circuit the battery! Therefore, the most senior electrical appliances are equipped automatic shutdown control circuit, the battery voltage down to 1V automatically turn off the power, and will not let you re-boot to protect the battery from being damaged.

Similarly, secondary lithium battery terminal voltage of 3.6V, full of electricity in the 4V or so, put End CLP 3V, should not let the battery into the 3V below. Dry batteries, nickel-metal hydride batteries and lithium battery discharge characteristics of different batteries of resistance greater, if the load is heavy, the battery terminal voltage will drop more, but the internal resistance of nickel-metal hydride and lithium on the little more, in the high- current discharge status, but also able to maintain closer to the nominal voltage. Early flash dry battery in accordance with this feature are designed, but replaced by a nickel-metal hydride battery, operating current will be too large, the circuit to burn, so we should pay attention to read the manual to see whether some kind of electrical appliances allows the use of rechargeable batteries. In addition, the discharge characteristics of batteries are relatively poor, its terminal voltage will gradually drop as the discharge process, for example, the new battery voltage of 1.6V, put 1 / 10 life becomes 1.49V, put 3 / 10, life expectancy dropped to 1.4 V, into the 5 / 10, life expectancy is declining for the 1.3V, into the 9 / 10 life of the terminal voltage becomes 1.15V.

The whole process of the voltage changed greatly. The characteristics of Ni-MH and Li-on is much better, and the discharge terminal voltage is always a smooth process, until a life is about to discharge to the end of the voltage, it has rapidly declined, and soon dropped to 1V, the end of cycle. There are a lot of friends ask about the battery charge, I would like to try to help you answer. Secondary battery charging direct current to the battery is used, "poured into" power, its principle is the so-called reverse chemical reaction. However, the discharge energy and the energy charge is not one to say, charging energy should be less than 1.4 times as large discharge of energy! ! ! For example, said, 1000mAh battery 1400mAh of electricity should be used as it can be filled with one-hour charge, it does not violate conservation of energy theorem, because the charging about 40% of energy into heat distributed. The standard charging method is to use 0.1 times the capacity of a number of current to the battery charging for 14 hours.

For example, or 1000mAh battery, I use the 100mA charge current to give it 14 hours. This charging method can guarantee that the battery is full, and the battery temperature is not too large (they do not feel them), charge a good enough battery capacity, battery life has reached the maximum. However, this charge too long, and in the use of inconvenient, so new chargers are designed to fast charge circuit, using a larger current to the battery charging, for example with 700mA current to the rechargeable battery 1000mAh 2 hours, so quick and easy to use, but the rechargeable battery will be hot when you not only the charge full enough, but battery life will also be a greater influence! (For example, had 1000 life has become 400 or even less). Are now more 1 hour, dozens of minutes of quick charger for the battery life of greater harm. So many of my friends think that quick charger is a good thing, a big mistake and the special wrong! 0.2 ~ 0.3 times the capacity with the number of current to the battery charging, the effect is still better, and closer to the standard charge time is shortened by half or more.

Battery charging current have more stress, if we adopt a stable DC current to the battery charging, electrode polarization very strong, and soon the electrode covered with a layer of chemical substances, isolated from its contact with the electrolyte, so that charging efficiency dropped After several charge after the increased electrode failure, finally dead battery is charging. The technical staff in this respect had several tests, using half-wave rectifier of the DC to recharge the battery, the battery's internal friction relatively large, resulting in greater heat will also affect the quality of charge to shorten the battery life. Charging waveform is definitely better frequency square wave, this wave can inhibit polarization and maintain the vitality of the battery is full nominal capacity, to achieve nominal life expectancy. However, the duty cycle square wave to have a design to stop charging time as short as possible to avoid the decline in the efficiency of charging too much longer.

The best way is to charge about 10 years ago by the United States, a company has developed, which uses 9 / 10 cycle, constant current charging, 1 / 10 cycle, stop charging, and, in the end during the insertion of a current major (2.5 times the capacity of a few), very short time (3ms) barbed discharge pulse, the pulse to the complete destruction of the polarization, and the electrode to maintain fresh, sufficient charge capacity, and even make the old battery to restore some capacity! The battery charge control a variety of methods. The first is the terminal voltage control method, that is, when the battery terminal voltage when the charge to a certain value is automatically cut off power supply, or converted to trickle charge (typically with a larger fast-charge current, close to capacity when the switch slow for small current charge, to improve the charging effect, known as trickle). This method is not scientific, because the specifications of each battery is fully charged after the voltage is different, we may cause overcharge or less filling. The second is the timing method, which is automatically converted to regular status after the value.

If you use the battery each time to give it 100% of capacity charge, this approach can be filled very full, and will not overcharge, in the circuit is relatively easy to implement. The third is the heat detection method, if the charging current is greater than the design, then the battery will start charging the end of fever, especially after a standard charge cycle, increase dramatically after the fever, when the battery is installed in the edge temperature components, we will send out the signal, the control circuit converted state. The disadvantage is that the law must be used to generate a larger charging current significant fever, or control are not sensitive enough, but also by environmental temperature. In particular, the charge is too high fever, very hurt battery life. Fever, when the battery is actually already in a state of overcharge! There is also a more advanced approach, the negative incremental method. When the battery reaches full capacity, its terminal voltage will be increased gradually turned into a sudden decline in a small value, which is the characteristics of secondary batteries, in the high current charging, this all becomes more obvious negative increment.

Using specially designed circuit to capture the negative increment, in turn control the charger is a very high-level design. The advantage of not causing the battery overcharging or less charge, do not have to pay attention to in order to charge the battery to be exhausted, but ready to add power. But, first, the negative increment only in the high current charging more obvious when, as we know, not ideal for high current charging method. Second, the negative increment of each battery is different from its detection is not very stable, if not detected, the battery will be too filling, so that damage or explosion, so the charger is also supplemented by a general Thermal detection of dual control. Third, the detection of a negative increment must address a single cell, if the battery for the series, due to the negative increment at different times, positive / negative increment will cancel each other out, so that detection fails. Therefore, the battery must be removed from a used appliances, respectively, into a specially designed in order to recharge the battery clip to give the use of inconvenienced. Fourth, the negative incremental detection circuit complex, specialized chips are relatively rare and expensive, so that the charger costs. At present, only a very small number of high-level charger using this structure.

Finally talk about the current charger products. Very much regret that the product is now more than 50% of chargers are unqualified (my view)! ! ! Many very senior electrical appliances, such as music players, cell phones, they wear no charger automatically stops charging control, let alone a waveform conversion circuit! I have studied a large number of such charger, internal mostly a transformer, a resistor, plus a diode, which is what I have said, half-wave rectifier charging, charging how much time your master (By the way, I forgot to explain, and for the small current charge, overcharge far greater than the damage caused by high current charging overcharge damage to light), but who can accurately remember the charging time? This overcharge is a common practice due to charge, normal charge effect is not good. Many mobile phone charger circuit appears complicated, in fact it is switching power conversion circuit, there is no automatic stop charge control, the effect is the same. Design ideal charger are often sold separately Shangyuan price of more expensive products, all with some sort of control circuit.

To this end, I have gone through many years of design and testing, final success of the works published in the "e-production" magazine, I think it merits is far from redundant in most other products. Many friends have asked about charging issues, read my article you will clear the charging time of the calculation is very simple, using a multimeter measuring DC current file click charge current, and then multiplied by 1.4 times the capacity of the Dell xps m1210 battery, then apart from this current is the charging time.

But the half-wave rectifier current value of the measure is too much trouble can not be directly measured electric table, need to use trial-wave devices, must also calculated that because as the charger but if you are half-wave, and do not stop charge control, I advise you to bar or throwing it away and buy a superior product, Do not expensive batteries (lithium batteries) to charge bad.