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    zyy2010
    zyy2010 is offline
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    1. The cradle charger of good quality (phone accessories wholesale) can tell the lithium batteries and nickel-metal hydride batteries and then decides the charge mode. There is an integrated circuit having the characteristic information of a lithium battery in the protection circuit board of Li-ion battery. The characteristic information can make the cradle charger tell the lithium batteries then determines the charging mode of "constant current" and "constant voltage". It also can make the cell phone tell the lithium batteries then determines the discharge mode and the call state.
    2. The charging mode of Ni-MH battery is “constant current”. Ni-MH battery itself is not afraid to overcharge. When it is overcharged it will have the reverse reaction which will heat the battery slightly to prevent excessive voltage rise. Ni-MH batteries usually add a thermistor to prevent the battery from overcharging. At present, the most cell phone’s operating voltage is 3.6V, so it needs three nickel-hydrogen battery cells. While the general Ni-MH battery stops charging after overcharging from 1.4V to 1.5V. The maximum voltage of three batteries is 4.4V.
    3. As the overcharging of lithium battery is dangerous, so the setting conditions on the charge and discharge is harsher than nickel-cadmium batteries and nickel metal hydride batteries. The internal lithium battery usually adds an extra control circuit board to prevent overcharge. According to the characteristic design of lithium battery, the charging mode at the first period is "constant current". It will change to the mode of “constant voltage" (between about 4.1-4.2V) to rechargeable battery when it will fully charged and then achieves its best. Some cradle chargers in the corner market think all the cell phone batteries as the Ni-MH battery and are charged in the mode of "constant current”, which is often easy to overcharge. The protection circuit board of good quality will protect the lithium batteries from the continue charging. If they are the poorly designed circuit boards, they not only fail to protect the battery, cause the battery from overcharging, but also may cause battery overcharging core deformation, leakage, explosion, etc.
    4. Commercial cradle charger often uses the fast charge. Usually it finished charging after three or four hours. When finished charging, there are only very weak electricity into the battery even if not to remove the battery from the cradle.
    5. It is not necessary to discharge often because Ni-MH battery’s memory is not good. While lithium batteries are basically without discharge. There are different discharge device of charger sold in the corner market. Poor quality device has the discharged phenomenon, which is easy to lead to the corrosion of negative plates inside the battery (Ni-MH battery inside the electrolyte is alkaline potassium hydroxide solution) and then reduces battery life and the normal use of capacity. In this case the battery would become bad faster if first discharge, and then recharge it every time. It is the best way to protect the battery that you don’t charge the battery until the cell phone is shutdown automatically.
    6. Domestically cradle charger mostly has the shortage of overcharge or charge. So you should be carefully when buying. For example, when recharging the battery after it runs out, it shows fully charged only a half hour. But its voltage is still low. Remove the battery from the cradle charger and then it continues charging.


    See More: The buying guide for cell phone battery charger
    Last edited by zyy2010; 05-19-2010 at 03:57 AM.
    http://www.goodscool.com




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