At present, electronics manufacturers for power supply more often use batteries based on lithium technologies: lithium polymer ( LiPo), lithium-ion ( Li-ion). The advantage of such batteries is that they have a large specific capacity, low self-discharge, the ability to give high currents during discharge, and such batteries are manufactured in all shapes and sizes. To charge these batteries, special chargers are needed.
Standard Batteries
Consumers often purchase devices that run on standard AA or AAA batteries. They can be replaced with conventional batteries and no special charger is required. Less and less often appear, previously used NiMH batteries. They have a capacity of 40% more than NiCD batteries. NiMH batteries are getting better every day. For example, if earlier their self-discharge was high, now some batteries have a minimum self-discharge.
Battery Charging Methods
When a battery is charged, chemical transformations take place in it. The energy that comes during charging, part of it is spent on these transformations, and part is converted into heat. NiMH batteries heat up more when charging than Nicd because the chemical reactions that occur when it is charged are exothermic.
The charge rate of the battery depends on the amount of charging current. The charging current is measured in units of C - the numerical value of the battery capacity. There are several types of charging:
drip charging (trickle charge) - current 0.1 C
fast charging (quick charge) - current 0.3 C
fast charging(fast charge) - current 0.5-1.0 С
Drip charging
With drip charging, a small current is chosen, because charging continues even if the battery is charged. With such a low current, the battery does not heat up so much. It is impossible to accurately determine the end of the charging process here.
Fast battery charging
Such charging with a current of 1C is not recommended for all batteries, because the battery vent may open at high temperatures environment(up to +40). When fast charging, you need to stop the charging process in time.
The fast charger operation algorithm consists of several phases:
1. Determining the presence of a battery
2. Battery qualification (Qualification)
3. Pre-charge (Pre-charge)
4. Transition to fast charging (Ramp)
5. Fast charging (Fast charge)
6. Top-of-Tcharge
7. Maintenance charge
Battery detection phase. Here, the voltage at the battery terminals is checked with the charging current generator turned on, approximately 0.1C. If the voltage is 1.8 V, the battery is missing or damaged. At high voltage charging should not start as soon as it is detected low voltage, charging will start. In the remaining phases, a battery presence test must be carried out, because in any phase the battery can be removed and the charger must return to the first phase.
Battery qualification phase. This phase starts charging the battery. This phase is needed to estimate the initial charge of the battery. Judging by the voltage on the battery, you need to determine whether pre-charging is needed or not.
Pre-charge phase. This phase should not last more than 30 minutes. The pre-charge phase is required for deeply discharged batteries. For all long phases, temperature control is required, it should not exceed 60 degrees during charging.
Phase transition to fast charging. It is not advisable to immediately turn on the fast current, it is better to gradually exceed it within 2 minutes. Fast charging can be started if the battery voltage is above 0.8 V.
fast charging phase. The most important thing in this phase is to stop the charge in time, otherwise the battery will collapse. To stop charging in time, you can use several methods to determine the charge.
For NiCd batteries the dV method is used - this is the fastest method for determining the charge; by the end of charging, the voltage on the battery decreases.
For NiMH batteries The dV method doesn't work so well. And use the dV=0 method. Here, the constancy of the battery voltage is detected. If within 10 minutes the voltage is the same, then it's time to turn off the charging.
Also, the end of charging can be determined by temperature, since by the end of charging, the pressure inside the battery rises and the temperature rises. Some chargers use pulse instead of DC. Current pulses last 1 sec. The advantage of this method is that it better equalizes the concentration of active substances throughout the volume, reduces the likelihood of the formation of large crystalline formations on the electrodes and their passivation.
Charging phase. In this phase, the charging current should be 0.1-0.3 C. The duration of recharging is 30 minutes, then there will be a recharge. After quick charge it is better to cool the battery and then start the process of recharging.
Maintenance charge phase. D.C harmful to the battery, as the battery will constantly have high temperature. After the end of charging, NiCd batteries go into drip mode to maintain the charge. And NiMH batteries do not tolerate overcharging and therefore maintaining a charge will do them little good. In principle, you can do without this phase.
Super fast charge
You can use current up to 3C. When the battery is 70% charged, reduce the charge and continue as normal. If this is not done, the ultra-high heating of the battery will destroy it or even explode.
"Smart" charger
Batteries of the same form factor. For example, AA size NiMH batteries have a capacity of 1900-2850 mAh, and AAA size batteries have a capacity of 750-1100 mAh. The charging current should be proportional to the capacity of the battery. When charging with a large current of a battery with a small capacity, there will be heating. When charging with a small current, the charging time will be long. In general, the charger must control the current, that is, use high current for batteries with a large capacity and small current for a smaller capacity. This is the meaning of a "smart" charger.
Charger power off problem
If the charger is powered off during the charging process, a transition to the battery presence detection phase should occur when the power is turned on. In this case, the charging starts again and the recharging will be carried out completely. The disadvantage of frequent recharging is that it can turn into overcharging. A "smart" Li + battery contains a controller that measures the amount of charge.
Primary current sources
Primary current sources are batteries (alkaline and manganese-zinc). The difference between primary sources and batteries is the internal resistance, which is higher for primary sources. If the internal resistance is greater than normal, the charging process will be interrupted.
Memory effect and battery recovery
The memory effect appears in NiCd batteries. The meaning of the effect is that large crystalline formations are formed on the electrodes, as a result, part of the volume of the active substance of the battery is no longer used. A full discharge is recommended to eliminate the memory effect. This complete discharge is recommended for NiMH batteries before they are charged. It will be better if you have a charger with a discharge function.
Interaction of batteries in an assembly
Separate accumulators in batteries can have different characteristics . Batteries that have a lower capacity will be destroyed during the discharging of the assembly. And each battery in the battery must be charged separately, but in the finished assemblies there are only two outputs and only a joint charge is possible. In this case, alignment is required.
To ensure that the car pleases you efficiently and uptime he needs to be taken care of. This is known to most motorists. However, many people forget this important element, like a battery, and they literally forget it. Indeed, during trips, the battery is recharged from the generator, which allows you not to think about it for a long time. But with regular downtime in traffic jams, the battery does not receive the necessary charge, while providing power to the on-board electronics. This leads to a gradual discharge. Can have a very negative effect on the battery long parking car. Unfortunately, this attitude sooner or later leads to the fact that car enthusiast is faced with the problem of a discharged battery.
Battery modern car needs to be serviced, while it is quite demanding on the quality of service. Using traditional transformer-type chargers, it is impossible to provide proper and perfect care for the battery. Moreover, a connection error or the selection of an incorrect charging current can damage the on-board electronics and lead to backfire. A separate problem is deep discharge, after which not all chargers can restore the battery to its previous level.
The BERKUT brand offers a range of SMART POWER smart chargers that will effectively solve many battery problems and ensure maximum battery life.
The family includes chargers different levels functionality that are designed to work with all types of 12 and 24 volt batteries. These are compact, convenient and easy-to-use devices with which you can easily provide not only recharging, but also efficient battery maintenance. Connecting the device to the battery is possible using crocodile clips or ring terminals. In addition, the SMART POWER charger can be connected to onboard network and through the cigarette lighter socket.
The key feature is that the device provides a phased charge. The operating cycle of most SMART POWER models consists of nine stages, during which diagnostics, restoration of battery properties, smooth charging with a gradual increase in operating current and its decrease after reaching a 70% charge level are provided. After reaching the 95% charge level, the charger monitors the battery's ability to hold a charge and switches to a saving mode. In this mode, additional charging is performed with small pulsating currents up to a level of 100%, after which the device turns off automatically. This mode of operation allows not only to carefully charge the battery, but also eliminates the possibility of overcharging and the problems associated with it. The car owner does not need to personally control the charging process, which takes place automatically. You can simply turn on, connect the charger to the battery and 220 volt network, and then go about your business, while the informative LED indication will allow you to fully control the work cycle.
SMART POWER is not just a car charger, but also an effective device for battery maintenance. In particular, the presence of a saving mode allows you to use the device for seasonal storage technology. The device can remain connected indefinitely. At the same time, it automatically controls the level of charge and, if necessary, provides additional charging of the battery up to 100%. This feature is simply indispensable for long periods of downtime. vehicle. For example, if you leave your car or ATV in the garage for the winter, then in the spring you will not have to deal with the problem of deep battery discharge and buy a new battery.
SMART POWER chargers can also operate in desulfation mode. After deep discharge or long-term storage in a semi-discharged state, lead sulfate from the electrolyte is deposited on the battery plates, which clogs the pores and significantly reduces its capacity. In this situation, the battery refuses to accept charging current. IN similar cases charging for car SMART POWER automatically turns on the battery recovery mode - Desulfation. The work program increases the voltage to a level of 17 volts and provides a charge alternating current. This makes it possible to restore the battery, which otherwise would simply have to be replaced.
Thus, the functional devices of the SMART POWER series allow not only charging the battery, but also significantly extending its service life. The use of these devices does not require any special skills from the driver and is not associated with the risk of damage and failure of the vehicle's on-board electronics and electrical equipment. In addition, a number of models can be used in the "Power Source" mode to connect devices with an operating voltage of 12 volts.
Pay attention to the whole range SMART devices POWER and do right choice for your favorite car!
one of the real significant benefits Android smartphones is to support fast charging technology. The iPhone, although it holds a charge well, but charging the “seven plus” to 100% is not a fast process. Flagships with a green robot are much better at this: modern fast charging technologies allow you to get several hours of work in just a few minutes of charging. But despite the fact that the technology is far from new, it is not yet present everywhere, and many people have questions about the principles of operation. What is fast charging for a phone, how it works, how to use it, let's try to explain in more detail.
Modern smartphones use lithium-based batteries. There are lithium-ion (Li-Ion) and lithium-polymer (Li-Pol) batteries, the difference between them is physical properties electrolyte filling the cell ("jar"). However general principle one: inside are available thin electrodes, and the space between them is filled with electrolyte.
When current is applied to the electrodes (which are positive and negative, + and -), physico-chemical reactions occur inside the battery, leading to the accumulation of an electric charge. When a consumer device is connected to the battery, reverse chemical processes occur, and the accumulated charge is given to the consumer. The flow rate of these processors is limited: the battery cannot be charged infinitely fast (there is a current limit, after which the speed no longer increases, and the cell begins to degrade), and cannot be discharged very quickly (the output current is limited by the reaction rate).
How does the battery charge
Physics lithium batteries is such that the speed of their charge in a smartphone is limited more features charging equipment than the cells themselves. Theoretically, the maximum charge current (not harmful to the battery) can be a current equal to the battery capacity (expressed mathematically as 1C, where C is “Capacity”, “density” in English). That is, if the capacity of the "can" is 4000 mAh, then it can be charged with a maximum current of 4 amperes (4000 mA). It sounds good: with such a power, it would take only 1 hour to charge up to 100% of some Meizu M5 Note.
But in practice, there are several restrictions that slow down the process of replenishing the smartphone with electricity.
- Need in soft start charging process. You can’t just take it (there should be a picture with Sean Bean in the role of Boromir) and immediately apply the maximum current to the battery: more, what good, it will swell or bang. Therefore, for a short time at the beginning of charging, it is required to smoothly increase the current to the maximum allowable.
- . As the charge is replenished and its density increases, the chemical processes inside the battery begin to proceed faster. Many will remember from a school chemistry course that the higher the rate of a reaction that occurs under conditions of excess energy, the more energy goes into heat. If thermal energy is released very quickly, overheating, electrolyte boiling and cell explosion will occur (hello Galaxy Note 7). Even if the battery does not explode, overheating harms it: the battery inflates, and its capacity decreases. To prevent the battery from overheating, as the capacity is replenished, the charge controller gradually reduces the current strength, thereby limiting the energy supply.
- Cable resistance. As is known from the same school course (only now not chemistry, but physics), an increase in current strength leads to an increase in the resistance of conductors. With an increase in resistance, they lose conductivity, and as a result, the lion's share of the energy will be spent on heating the contact circuits before reaching the battery. An ordinary cable that connects a computer or TV contains two or three thick cores (more than 1 mm in diameter), and therefore can withstand currents up to several amperes without overheating. When such currents are applied, the thin strands of the charger cable will simply overheat and burn out in the weakest area (for example, in the place of frequent bends). Therefore, the cable also interferes with high-speed charging.
- . Like the cores of the charging cable, the tracks on the smartphone's motherboard are very thin, and therefore, when currents are applied great strength they will overheat and burn out. As a result, manufacturers have traditionally limited the charging current to 500-1000 mA (0.5-1 amperes), and in this situation it takes at least 4-8 hours to charge a 4000 mAh battery in Xiaomi Redmi Note 3 Pro.
Fast charging - what it is and how it works
Fast charging is a conventional name for a set of technologies and techniques designed to increase the speed of battery charging by eliminating or bypassing the above restrictions: charging start and end currents, the resistance of the charger conductors and the smartphone itself. In order to make the charging process faster, manufacturers use several tricks.
- The need for a smooth start of the charging process virtually eliminated: modern chemical compounds, used in batteries, "swing" very quickly, and as a result, the battery can be charged with full current (1C) in about a minute after power is applied to it.
- The need for a smooth decrease in the charging current For lithium cells basically irremovable. It is impossible to make sure that the battery is constantly charged with a current of 1C up to 100%. Here the task is reduced to finding methods to minimize the time required for charging in the reduced current mode. Intelligent charge controllers analyze the state of the battery to determine when to charge it powerful currents is no longer possible, and they begin to limit the supply of energy.
- Cable resistance overcome by using high-quality conductors from an oxygen-free core. Connectors are also being improved: their downforce increases by creating tighter contacts, and resistance losses are reduced by gold-plating contacts. Due to this, the resistance of the wires is reduced, allowing more amperes to be supplied.
- Board track resistance It is “treated” in a similar way: wide and thick tracks are used in power lines, and charge control chips are made resistant to high currents and voltages.
But it will not work to increase the current indefinitely, since even an ideal cord, due to its small thickness, will get very hot at high currents. Since the power is equal to the current multiplied by the voltage, along with the amperes, the voltage also increases. That is, charging with a voltage of 5 volts (V) and a current of 2 amperes (A) has the same power as charging with a voltage of 10 V and a current of 1 A, namely 10 watts.
The task of a charger with fast charging support is to supply high power, choosing the optimal ratio of volts and amperes. The task of the charge controller is to monitor the battery and tell the power supply what voltages and currents can be applied to the smartphone.
Based on the foregoing, several components are important for organizing fast charging in a smartphone:
- High-quality battery, created according to the most modern technologies, and does not require a long "buildup".
- A special controller that will analyze the state of the battery, determining what voltage and current can be applied to it at the moment.
- A well-implemented charging circuit inside the smartphone: a good connector, thick tracks, a hardy controller.
- Power supply with support for fast charging, capable of supplying large currents and voltages.
- High-quality cable with durable oxygen-free copper conductors and reliable connectors.
The combination of these elements allows you to quickly charge your smartphone. If some components are missing, there will be problems with the implementation of an accelerated charge.
Poor quality charging cable prone to overheating If you are going to buy batteries, but you don’t have a charger yet, or you want to buy a charger to replace the old one, then the question inevitably arises - which charger to buy, what to choose from a huge variety?
Why do you need a quality charger?
The service life of quality NiMH batteries at proper care behind them is an average of 3-5 years. Capacity modern batteries comparable to the capacity of expensive alkaline (Alkaline) disposable batteries, but unlike them, batteries can be used from 500 to 3000 times. The benefits of buying batteries are obvious!
In order for the batteries to serve for a long time and work efficiently, it is necessary to choose the right charger. A common mistake many buyers make is to buy expensive high-quality batteries and buy a cheap charger or use an old one bought a long time ago. As a result, even the most expensive batteries will quickly fail.
There are at least 3 reasons why you shouldn't skimp on your charger:
1. Cheap chargers can charge batteries extremely slowly - up to several days;
2. Cheap chargers do not allow you to control the charging process, they may not have automatic shutdown after the battery has finished charging. You have to "by eye" calculate the charge time, it is not convenient and not accurate - batteries can either be undercharged or recharged;
3. Cheap chargers do not have protection against overheating and overcharging of batteries, which shortens their service life.
All these factors negatively affect the quality of the batteries, as well as significantly reduce their service life.
Problems can be prevented or solved with a quality charger. Manufacturers offer a variety of chargers aimed at a wide range of consumers: from advanced users who want to have full control over the process and battery charging parameters, to ordinary buyers who do not want to know anything about the battery charging process.
What should be considered when choosing a charger?
When choosing a charger, pay attention to the following important points:
1. Availability of independent channels for charging each battery separately
Many cheap chargers only charge batteries in pairs. This creates a number of inconveniences in use. First, you need to make sure that the pairs of batteries that are used in devices are not confused. Secondly, many devices use an odd number of batteries that cannot be charged in such a charger. Have to look for some additional battery to complement a pair for charging, which is very inconvenient.
In addition, over time, the batteries in a pair begin to differ in capacity, which affects the duration and quality of the pair. The difference in capacity can reach such an extent that due to one undercharged battery, the steam practically stops working and it becomes impossible to use the batteries.
for АА/ААА+KRONA
for Li-ION+АА/ААА:
For Li-ION :
TrastFire TR-001
4. The presence of the "discharge" function
The "discharge" function is very useful feature, which allows you to extend the life of batteries and maintain high performance their work. The fact is that batteries are considered discharged when the voltage on them is 0.9 volts, while many electronic devices turns off when the battery voltage drops only to 1.1 volts or more. When charging an incompletely discharged battery, over time, a “memory effect” appears, which consists in the loss of battery capacity and a decrease in the duration of its operation.
To prevent the "memory effect", it is recommended to completely discharge the battery before charging it. It is possible to discharge the battery with a flashlight or motorized toy, but there is a risk of over-discharging the battery. If the battery voltage drops below 0.9V, the smart chargers may perceive it as faulty and not charge it.
Therefore, to discharge the batteries, it is recommended to use chargers with the "Discharge" function.
When using batteries in toys or flashlights, do not allow deep discharge batteries. If you see that the battery is already dead (the flashlight shines dimly, the motor in the toy spins weakly or the sound is distorted) - replace the batteries.
5. Availability of additional functions and features
Currently, the most popular are intelligent chargers that allow you to independently set the charging and discharging currents of the batteries, overclock the battery capacity, measure and restore the battery capacity.
Buying such a charger makes sense if you use batteries all the time and need to be sure of the capacity and performance of the batteries, or if you just like to experiment and explore. Also, such a charger is a great gift for anyone who uses batteries.
Intelligent chargers:
Separately, it is worth noting the intelligent chargers of the device, which are equipped with various additional accessories: AA and AAA batteries, travel bags, adapters. The quality of complete batteries and accessories is usually quite high, and the cost of batteries in a set is usually lower than the cost of similar batteries separately. Therefore purchase chargers with accessory kits can be very beneficial.
Intelligent chargers with accessory kits:
Among smart chargers, advanced chargers can be distinguished. These chargers are distinguished by the presence of additional functions and capabilities: screen backlight, measurement of the internal resistance of batteries, a wide range of charge and discharge current settings, manual installation the number of charge / discharge cycles for training / overclocking.
Advanced chargers:
6. Ability to work with batteries of different formats and sizes
If you are using batteries different types(Ni-MH, Li-ion) and different sizes In order not to buy a separate charger for each type of battery, you can purchase a universal charger that is suitable for charging several types of batteries. Universal chargers are no worse than individual chargers for each type of battery. In terms of functionality, they can also be either simple, which simply charge batteries, or advanced, which can charge, discharge, test and train batteries, and measure their capacity. Universal chargers combine the ability to work with Ni-MH batteries in sizes AA, AAA, C and Li-Ion batteries in sizes 18650, 14500, 16340, 26650, etc.
Universal chargers:
7. Ability to work with a large number of batteries
There are situations when it is necessary to charge many batteries at the same time - 6 -12 or more. It is quite obvious that the use of the most common chargers for 4 batteries in this case inconvenient, the charging process takes a long time and requires extra attention. Using multiple chargers can also be an inconvenient solution to the problem. ROBITON VolumeCharger
8. Super-fast chargers.
More and more are on sale Li-ION batteries with high load capacity, for electronic cigarettes, power tools, powerful flashlights. In most cases, these batteries can be charged quickly without affecting their lifespan. For these purposes, special chargers are produced that allow the use of maximum currents charge for Li-ION batteries:
As a summary, it can be said that in order to charge high-quality batteries, it is advisable to purchase a high-quality charger that will provide long term battery life and performance. Choose the optimal charger, which in terms of its functionality will allow you to work with your batteries at the level you need. Before buying, it is also advisable to think about whether you will need additional functions in the future, even if you don't intend to use them now.
Thank you online store
http://batterex.com.ua/ for the materials provided
Intelligent Charger Kweller X-1800
I’ll start the review with the main question “why do you want to buy an intelligent charger (charger) so much?” Why not just buy a cheap charger for 300-400 rubles and charge your batteries with it? I will try to answer this question in my post. So:
Opportunity: Int. memory. Simple memory. A comment
Automatic charge Yes. NO. Overcharging leads to rapid battery failure.
Correct discharge Yes. NO. Full discharge leads to battery failure. You can only discharge up to 0.9-1 V.
Overheating control Yes. NO. Overheating of batteries leads to its destruction.
There is a possibility of recovery. NO. Part of the batteries that we sometimes throw away because. they do not hold a charge, are recoverable
Individual charge Yes. NO. Most chargers charge batteries, in pairs and by charging different batteries together, we unknowingly spoil them
There are many others important features, but by switching to the Kweller-1800 Smart Charger, I was finally able to relax. Previously, I constantly checked the residual voltage on the batteries with a multimeter, so that when charging them in pairs, I would pick up a colleague so as not to overcharge one and undercharge the other. I tried to discharge not completely discharged batteries manually using a trimmer. Due to the fact that there was a case when my battery overheated and the charge leaked solidly, out of habit I periodically approached and felt the batteries. ... But this is all in the past, I have a Kweller-1800 in my hands, which I purchased in an online store. 
The package includes an intelligent charger, power supply, instructions in Russian, and what is not unimportant is a 3-year warranty.
As you can see in the photo, Russian is also included in the number of languages on the package. 
Immediately striking quality assembly and the presence of a large number of side and slots on the bottom for ventilation. 
Here are the specifications of the device:
Adapted network plug for Russia. No additional adapters to buy
Works with all NiCd and NiMH “AA” and “AAA” batteries
LCD screen shows information for each battery separately
Can charge “AA” and “AAA” size batteries at the same time
Detects bad batteries
Ability to select the power of the charging current for each channel
Automatic switching to trickle charge when charging is completed to ensure maximum capacity batteries
Charging automatically starts with a current of 200mA ( optimal mode to prolong battery life)
Ability to set charge currents 200,500,1000,1500,1800
overheat protection
3 buttons providing easy control
Charging Mode
Discharge Mode
Recovery Mode (may take a long time)
Test mode (determining the current capacity)
The characteristics are good, but the most important thing for me was to try it out right away. Just for this case, I typed specifically different batteries, plugged the device into the socket and started the test mode (Test). Let me explain, I didn’t even begin to figure out which ones I had charged, which ones were discharged - a smart device will understand everything by itself. 
The device started charging the batteries. By default, it took a charge current of 200mA and displayed this information on the display. With the “Display” button, you can change the displayed information to: Current voltage, Elapsed time, Accumulated charge mah.
After a couple of hours, the battery "without a name" in the photo, it is light green in color, switched to Discharge mode. I keep a small amount of low-capacity Chinese batteries in order to power devices that have a small current consumption, for example Wall Clock. The cost of such batteries starts from 40 rubles / piece, so they will always find their niche. The only thing left to guess about the real capacity of such batteries is nothing Kweller X-1800 will help us with this. 
The process took a day, during which I took out the batteries and wrote down the data in the table. And so as a result I got the following picture:
Battery. Year of purchase. Case capacity. Tested capacity.
Varta Ultra AA 2005 1700 1312
NoName АА 2012 2300 252
Huanyu AAA 2004 550 344
Camelion AAA 2012 1000 713
The most shock from the "light green" for 40r. - 252 mAh. It's a gesture, as in modern technologies China can produce a product of this level .... The old Huanyu is still quite suitable for the remote control to the TV. Varta - after 5 years it still pulls.
Let's see what this charger can do with these instances in Refresh mode. Let me remind you that this mode performs several charge-discharge cycles (restores the lost capacity as a result of incorrect operation). The process is long but rewarding. And so after 2 days we see that the capacity of most batteries has increased. In some "advanced" cases, recovery can be up to 50%.
Battery.Year of purchase.Capacity on case.Capacity after first test.Capacity after refurbishment.
Varta Ultra AA 2005 1700 1312 1569
NoName АА 2012 2300 252 1920
Huanyu AAA 2004 550 344 395
Camelion AAA 2012 1000 713 804 
Charging has 2 more modes in addition to those described above. These are automatic charging (Charge) and discharge mode (Discharge). The first mode simply correctly charges the inserted battery. But on the second I would like to dwell in more detail. Ni-MH batteries and Ni-CDs have a "memory effect". When you insert a battery that is not fully discharged for charging, it does not charge to its full capacity when charging. This "wasted" capacity is negligible on a single charge, but if you constantly charge a battery that has a residual charge, the effective capacity is reduced. It is recommended that every 5-10 charges do one discharge of the batteries to 0.9-1.0V (not completely, a complete discharge is very harmful, namely up to 0.9-1.0V) and then immediately charge. Just as described important process and implements the Discharge mode. With the Current button, you can set the discharge current to 100,200,350,500. But you need to remember that after discharging, the charging of currents will start twice as large as the discharge current is set. 
It is very useful that when you select any of the modes you have chosen, at the end of the process you will receive a fully charged battery.
The device allows you to select for each of the 4 places for charging / discharging / testing / restoring batteries your own current, but there can be only 2 modes. For example: you restore the first two batteries, and charge the second 2, or you can put 2 compartments for discharge, 2 for charge.
Dismantled the device, I wanted to see what's inside)) 
As you can see in the photo, the soldering is quite neat. After disassembly-assembly, the device worked as if nothing had happened)).
Conclusions:
Minuses:
You can install no more than 2 modes on all batteries.
No display backlight
Not a cheap device (I bought for 1300r). You can probably find cheaper, but I do not like to wait for a long delivery from abroad.
Pros:
Pleasant both to the touch and to use the device. You no longer have to worry about charging, the device does everything by itself, so it’s also correct.
Intelligent system correctly charging AAA / AA batteries of any capacity and workmanship.
High charge current 1800 mA (Useful if you don't have spare batteries and need charged ones within 30 min. useful feature)
The microprocessor filling controls all the parameters necessary for a long battery life in all operating modes.
The ability to operate batteries as efficiently as possible using the entire range of charger modes.
Warranty 3 years.
Conclusions:
A very interesting device. A device that can be trusted with any batteries, even the most expensive and very capacious ones. With a large margin for the future in terms of current (up to 1800mA). In many respects, it is an analogue of La crosse BC-1000, but at a price lower than La crosse BC-700.
