Battery Discharge methods
The purpose of the battery storage and release of energy in a controlled manner at the appropriate time. In this section, we examine the different C-discharge rate and evaluation of the depth of which the battery can be safely discharged from hospital. We also observe how deep discharges affect battery life.
What is C - rate?
Charging and discharging of the battery current measurements in C - the rate. Most portable batteries rated voltage of integrated circuits. This means that, 1000 mAh battery will provide a one-hour 1000 milliamperes if the 1C-rate discharge. The same batteries -0.5 ℃ discharge will provide 500mA for two hours. In 2C, the 1000mAh batterytoshiba PA3285U-1BRS battery， toshiba PA3285U-2BRS battery， toshiba PA3285U-3BRS battery can only provide 30 minutes of 2000 milliamperes. 1C is usually referred to as one-hour discharge; 1 -0.5 ℃ will be a two-hour, and 0.1 ℃ 10 Xiaoshi discharge.
The battery capacity is usually the battery meter. If the tester the ability to read out the name displayed in the percentage of score, 100%, indicating that if a 1000mAh battery can provide such a current of 1 hour. If the battery is only 30 minutes before cutting off a sustained, 50% of that. Sometimes a new battery offers more than 100% capacity.
When the discharge of the battery analyzer, which allows setting of different discharge dirty rate, higher-capacity battery is reading an observation, if the battery discharge to a lower C-rate, and vice versa. 2C, through fulfilling the 1000mAh battery, or 2 thousand milliamperes, resulting in size analyzer within 30 minutes of full capacity. In theory, reading ability, should be the same discharge slowly, because the same amount of energy dispensed only in a relatively short time. Due to internal energy loss and voltage drop, causing the battery to achieve low-voltage cut off faster reading skills may be reduced to 95%. -0.5 ℃ in the discharge in the same cell, or 500mA over two hours to improve the reading skills of approximately 105%. With different reading ability differences in rates of C is the battery internal resistance.
A battery, does not perform to 1C discharge rate is the portable sealed lead-acid. To get a fairly good reading skills, the manufacturer is usually the rate of 0.05C or 20 hours, the battery discharge. Even in this slow discharge rate of 100% of the capacity is very difficult to achieve. In order to compensate for the different readings of different discharge currents, manufacturers offer the ability to offset. Use the correct offset reading ability improve battery performance, it is only the calculation of adjustment ability, if higher emissions, lower C, or below the stipulated ratio.
Lithium-ion battery of electronic protection against high load currents. According to battery type, discharge limited to between 1C and 2C,. This protection makes the lithium-ion bio-medical equipment and power tools, require a high surge current inappropriate.
Depth of discharge
In the end of discharge voltage of typical nickel-based batteries 1V/cell. In the voltage level, approximately 99% is used for energy and voltage began to decline rapidly, if it continues to perform. Beyond the cut off voltage of discharge must be avoided, especially at high load.
As the battery cells can not completely match, a negative voltage potential, also known as cell reversal, the country will appear weak cells, if allowed to continue unchecked emissions. The more batteries in series, the greater the likelihood of cell reversal.
Nickel-cadmium battery can tolerate a reversal, which is typically about 0.2V to. During this period, the positive electrode polarity reversal. This situation can only be maintained for a short period of time, because the positive evolution of hydrogen and possibly lead to pressures to build up cells exhaust. If the battery voltage is reversed into the further, the two electrode polarity is reversed, the cells generated by short circuit. Such failures can not be corrected.
Some battery analyzers apply secondary discharge (renovation) of the battery voltage discharge to a very low voltage cut-off point. These instruments control the discharge current in order to ensure the maximum allowable current, while in the sub-discharge range, does not exceed safe limits. If the cell reversal of development, will be low enough not to cause harm. Cells through the refurbishment of the figures may be a weak or aged pack.
If the battery discharge rate higher than 1C, the final discharge point of the nickel-based batteries are usually reduced to 0.9V/cell. The compensation from the induced cell internal resistance voltage drop, wiring, protection devices and contacts. The lower cut-off point of the ability to produce good readings when the battery discharge at low temperatures.
In the chemical batteries, nickel-cadmium is least affected by repeated full discharge cycles. Thousands of charge / discharge cycle is possible. This is why nickel-cadmium done well, for power tools and two-way radio, the regular use. Nickel-metal hydride less durable in repeated deep-cycle.
Lithium-ion batteries are usually discharged into the 3.0V/cell. Version of spinel and coke can be discharged into the 2.5V/cell to get a few percentage points. As equipment manufacturers do not specify the battery type, most equipment is designed to cut off 3 volts.
2.5V/cell emissions may fall below the battery protection circuit to sleep, to prevent ordinary charger. These batteries can be recovered with the step-up program cadex c7000 chassis toshiba PA3383U-1BRS battery， toshiba PA3395U-1BRS battery， toshiba PA3399U-1BAS batterySeries battery analyzer available.
Some lithium-ion battery has an ultra-low voltage cut off, permanently disconnect package, if a cell dips below 1.5V. A very deep discharge may lead to the segregation of copper to form a short circuit may lead to partial or total. Similarly, if there is battery-powered to the cathode, and in the state to maintain for some time.
Manufacturers rate of 80% of the lithium-ion batteries depth of discharge. Repeat All (100%) of waste emissions, reduce the specified cycle count. It is therefore recommended rechargeable lithium-ion more often rather than letting them take the fall too low. On a regular basis without a comprehensive disarmament, because the lithium-ion battery is not affected by the memory.
The proposal, eventually leading to the discharge voltage acid 1.75V/cell. Dismissal of nickel and lithium that do not follow the preferred flat curve-based chemicals. On the contrary, lead-acid with a rapid decline in the discharge end of the voltage is gradually decreased.
In the life of sealed lead-acid is directly related to depth of discharge. A typical number of discharge / charge at 25 ° C (77 ° f With regard to the depth of discharge) cycle is:
150 - 200 100 Discharge (fully discharge% depth of cycle)
400 - 500 50 discharge (partial discharge% deep cycle)
1000 and more than 30 discharges (% shallow depth of discharge cycle)
Must not emit more than lead-acid batteries per unit 1.75V, and should not be in the discharge state. A discharge lead to cell acid sulfate, a condition so that the battery is useless, if left a few days in the state. Always maintained at 2.10V and higher open terminal voltage.
Discharge current and the load signature
Rechargeable battery is tolerant wide range of load signatures. In the cycle of life, constant current discharge conditions, is superior to digital loads. Figure 1 reveals a cycle of nickel-metal battery for laptop hydride battery provides a number of different load conditions. Can be seen that the greatest loss of capacity in the digital load, such as mobile phones. Increase the resistance of the main reasons for premature failure.
What constitutes a discharge cycle?
Does not constitute a discharge cycle of standard definition. Smart battery discharge cycle commonly used to keep track of the 70% discharge depth of the definition of discharge cycles. Any less than 70%, does not count. The reason is that the cycle count is estimated at the end of battery life.
A battery often receives many short-term emission of charge. With the smart battery, these cycles does not count, because they stress the battery very small. In the satellite, the depth of discharge, only about 10%. This micro-discharge cycle the batteries in the smallest space, the stress. Light emission, however, nickel-based batteries require regular deep discharge to eliminate memory.
Lithium batteries and lead batteries do not need to fully implement a regular basis. In fact, it is best not to carry out their deep, but they charge more often. Use a larger battery is one way to reduce the pressure on the battery.