1.1 Load floating down

There are many base stations, maintenance personnel were not according to specifications, according to the manufacturer requested that the float voltage set to 52.7V, an average of 2.20V / month. In this charging voltage, due to valve battery back-EMF above 2.19V / a, once the landfill, although there “was sufficient” link, but with a float voltage of 0.01V efficient pricing, loss of capacity is not possible to load circuit was added. Many people believe that float voltage difference of less than 1V there are no major effect on the capacity, should distinguish between the table of voltage command displays the name of the closet Um charging voltage, the actual output of the IBM ThinkPad R51 battery voltage Us, and effective charge difference of tension between the three Uy a basic concept. EMF-based batteries Uf is the relationship between these parameters are:

Uy = Us-UF

For example, the voltage meter shows 54V Um, the whole battery of practices we are 53V, the battery back-EMF is Uf is 51.6V, the charging voltage of the battery Uy effective 53-51.6 = 1.4V.

Only a review of this concept, it means May float voltage below 1V small fluctuations, it will keep the battery capacity of the underlying causes of the considerable influence.

From Figure 1 we can see the curve of charging batteries, 500Ah battery discharge after the float voltage of 2.23V, the capacity can be quickly restored to 66%. Under the conditions of the float in the 2.29V, the corresponding value is 75%. This means that the discharge of the battery capacity fully restored need many days to complete.

Having a base station, the battery installed in the exchange, after a power failure after the time power is independent of 8 hours, 2nd time was 6 hours, 3rd is 4 o’clock. The share of users is the result of poor quality batteries. Instead, this example illustrates the lack thereof will result in a Dell Inspiron 1525 battery to retain the capacity reduction in the structural capacity of the battery can not charge and discharge cycles three times, but fell by 50%.

The base station is valid for the charging voltage is 1.4V. The voltage drop of 0.4V, the charging effects will be reduced by 30%.

Table 1.2 shows the high voltage.

Control cabinet table shows the high voltage is often the case, defenders under the control panel of this table shows the value of the adjustable float voltage, if the spectacle of high K, the battery must be the real float charging voltage on low K Check the ark of the digital voltmeter belonging to measuring devices, measurement tools, management must be calibrated on a regular basis. Talking about here is the tension “and the actual display calibration voltage,” not now remotely operate a float level adjustment of tension. “This work is now maintenance procedures did not apply. Many technical staff do not even know these two are totally different concepts of technical content. Ark of the control voltage show that is to pass the total hp 346970-001 battery voltage analog circuit is converted to 5V below the weakening of the signal to be the computer to recognize. The process of converting analog circuit produce attenuation bias, this part of the detour is necessary calibration and eliminated. Therefore, we use a multimeter require regular calibration and maintenance of technical standards is now no maintenance requirements in this regard is the need to introduce additional criteria for the content. 240 base stations in the survey itself, a control panel of display bias voltage to 0.9V.

1.3 to adapt to low voltage.

Some manufacturers of batteries, the battery is stated on the box, the battery charge voltage of 2.20V to work, “which is to deceive the user. Some staff management in accordance with the “factory requirements, the base station float voltage regulated to this value, resulting in a wide range of batteries are ensuring that there is state capacity. Manufacturers of batteries such a provision is to protect the interests of the factory battery in the float low voltage conditions, water loss from the battery to the less positive grid corrosion is small, the battery will be prolonged. Manufacturers Battery can not bear to maintain capacity due to low, resulting in “off station” ’s liability, but does not engage in the state of the VGP-BPS13 battery is charging less than the liability for damage caused by polymerization.

1.4 behind the battery backup for high EMF

The batteries in series, if one behind the battery, battery back-EMF is increased, the average voltage of 2.23V battery pack, can sometimes be detected by a single voltage of 2.60V. In this state, the control panel in the computer detects the charging voltage was increased, yet there is no battery to a predetermined capacity, they have been wrongly identified as “a been filled to a predetermined value, put the load current, leading to charge less than the actual state of operation of the battery, it happens often. A number of base stations, the two batteries in parallel. In parallel, under conditions of use, the cost of current distribution imbalance occurs, such harm is a way of accelerating development.

1.5 After dehydration against electrolyte, the electric potential and the increased density of condensed

The toshiba PA3421U-1BRS battery is losing the use of water, but do not reduce sulfate density of the electrolyte to increase the battery back-EMF Uf upward, battery back-EMF and density dependence of the relationship between the value of d is:

Uf = 0.85 + d

EMF is a direct consequence of the increase in real decline charging voltage. The end result is charging enough. In the float conditions, the battery must be a true no-load back-EMF voltage and current-voltage and polarization. Bias voltage and intensity are directly related.

Battery water loss is inevitable, the higher the temperature, the rapid loss of water. Commonly called “temperature of 10 ℃, the life expectancy reduced by half,” the law, the actual increase was mainly due to the temperature of the water caused by acceleration lost; temperature increase caused by the Corrosion is secondary. In Luoyang recharge the battery of 30 base stations, the statistical average for each refill 500Ah batteries 800mL, reaching the level of the plant. The calculation shows that compensation of overtime before the electrolyte density, condensed from 1.30 to 1.37g / cm 3, and anti-electric potential to rise to 2.22V. In fact, do not measure such a high electromotive force is due to some of sulfuric acid has been converted into lead sulfate consumed. In the charging voltage of 2.20V, so that apple MacBook Pro 15 inch battery power can be added. Pay on time, not only to protect the battery to run quality, but the real life of the battery in the south of the original 2-year to five years or more, if not rapidly lost battery of additional water, will result in damage to many non-use.

Lead-acid batteries discharge, the positive and negative electrodes on the active substances are converted into lead sulfate PbSO 4, but delays of sulfuric acid micro structure is loose, was cavernous. Then the plates are still in the high energy potential, if the residence time is longer, most would approach the board of crystals of lead sulfate of high potential energy state to a state of low potential energy. At the microeconomic level, is to head PbSO4 Re sulfate crystallization of the initial loose on the left into the right shape to phase plate when the batteries are vulcanized on the state, and indicate the process illustrated in Figure 2. This damage has occurred in the negative, the burden of positive plates produced when the oxygen atom has the ability to PbSO4 in PbO2 lead sulfate, it will not heal the injuries of the positive plate.

Not difficult to understand, the batteries have a longer time on the minimum requirements of state capacity of lead sulfate on the substrate are more cellular damage occurs sulphide. Float electrician normal conditions, batteries will not sulfide.

Every single lithium-ion batteries in parallel on both a shunt resistor. As seen from the circuit, the shunt resistor current must exceed the battery discharge current to reach a balanced load effect. General lithium-ion battery discharge current C/20000 as such, it flows through the shunt resistor on the current use C/200 is more appropriate.

In addition, each effects bias shunt resistance are also important factors affecting the balance. After a number of load cycles of discharge, the difference of a single cell can be determined using the following formula:

V battery voltage shunt type = R × I self-discharge 2 × V × single cell polarization resistance K

If the shunt resistance to 20Ω ± 0.05%, while the gap voltage Laptop battery can be controlled to within 50mV range. The average power of each resistor 0.72W, but whatever the process of loading the battery or the process of discharging the battery, shunt resistor still consume energy.

2. Removed balance shunt resistor

Equilibrium Charge-off shunt resistor shunt with the difference in resistance between the equalizing charge is adding an on-off switch, this button switch can be achieved by the SCM system software can also be done by a simple logic circuit to achieve. Circuits using this control method only charge balanced type a constant voltage phase of work, other times on-off switch is always off, so the discharge of the battery needed, the shunt resistor does not consume valuable energy. In the period lighting, solar energy production, there is a surplus, when a balanced circuit consumes a certain energy to the system power supply to a certain degree of rationality. In the orbit of satellites in low orbit, such a balanced circuit only 10% of working time in order to obtain a balanced effect discussed above, the resistance value is necessary to reduce by 10 times, showing that the peak Thermal power is very large, it is such a circuit the main drawback. In addition, the effectiveness of on-off switch is a fatal failure, it is necessary that the redundancy of resources.

3 Switched-capacitor charge balances 

one can see from the table, sequence switching circuit driver mainly by the clock circuits, which drive multi-channel change the order of closure, the The order of lithium-ion VGP-BPS10 battery access monomer transmission capacitor, by transmitting the imbalance between the energy of a single cell to achieve a balanced application of load. At the same time, by measuring the voltage on the capacitor sent to monitor every single cell voltages. If one cell short circuit fault occurs at low output voltage comparator to switch ban signals, prohibit access to short-circuit the battery to send a single capacitor, to avoid affecting the activities normal cell only alternative to both the constant current constant voltage converter in the battery low voltage alarm, so that constant current constant voltage converter in a single cell to short-circuit conditions to determine the constant voltage correct. The biggest advantage of this circuit is a balanced energy waste is very low, the drawback is that the circuit complex, multi-way switch on resistance state, the upper limit of common mode will affect the achievement a balanced load. On the other hand, the selection of parameters is difficult, a different configuration of power system, the circuit parameters required for detailed design and verification, which is detrimental to the development cycle.

4. step-down converter load equalization

Buck Converter is also a balance of low power charging solution for the rest of the program. It is very good idea, the main circuit is a standard male-type regulator in the inductor energy to add multiple sets of the same sub-windings, for single auxiliary VGP-BPS13 battery charge. Clearly, the low voltage single cell sub-windings more energy, a high voltage to be less energy, so that the aim of achieving a balanced load. To achieve a good balance of effects, sub-windings of the coherence of the need for strict control. However, the consistency of the inductor winding is very difficult to master, so it’s such a control method of a greater disadvantage. This study has just started to load, efficiency, balance of performance, reliability analysis, the need to continue in the study.

5. The average balance of tension load cells

The average balance of cell voltage charging principles as shown, 1 shows only a single cell balance circuit, the only other cell is also equipped with an identical balanced circuit, from which a single battery-powered amplifier.

Such a balanced load control circuit of thought is: single-cell voltage and medium voltage single cell compared to the control power switch to the battery voltage is above the average voltage of segregation unicellular. Therefore, all tension of the single cell balancing under the effect of the circuit tends to power the cell average.

At first glance, this circuit is the open loop control, in fact because of the role of the VGP-BPS11 battery internal resistance, a balanced circuit with negative feedback characteristics in the state closed loop. To prevent discharge circuit of the battery in a time of balanced work, you can reduce the power regulator switching diodes in series, so that the discharge of the battery, the battery voltage is low and the loss of shunt circuit.

The average balance of cell charging voltage circuit model has in-depth study is considered the result of a very good program. This circuit has been included in the LEO orbit lithium-ion battery applications, the preferred program, filed a patent application in France and Europe.