These batteries rightfully deserve such reviews as "the most fastidious, dangerous, unreliable and short-lived", but despite all these shortcomings, the use of these batteries is growing rapidly, as they have an unsurpassed indicator of specific (per mass) energy, and are also capable of delivering large discharge currents. So for power electric motors, there is practically no alternative to these batteries yet.

We briefly list the basic rules for operating LiPo batteries, giving below detailed explanations of the reasons for those interested:

1.When charging LiPos, only charge them with a dedicated LiPo charger and only under supervision. In the event of any internal damage during charging, spontaneous combustion and fire may occur.

2.Never charge the battery without a balancer - a device that controls and equalizes the voltage on each "bank" in a series-connected battery. For devices like iMax B6, G.T.Power A6 and the like that have a built-in balancer and a choice of charge methods, always select Balance Charge mode instead of just LiPo Charge. The latter does not balance or control each of the cans.

3. For charging, use a current of no more than 1C if you are in the field, and about 0.5-0.7C at home. According to some reports, a slower charge will extend the life of the battery. Addendum: Some newer battery types like the Hyperion G3 allow charging currents up to 5C. In this case, such a charge can be recommended in the field, and at home - 2-3C will be enough, although 1C at home will not make it worse.

4.Never allow the battery to be deeply discharged, as She is irreversibly disabled.

5. If possible, do not bring the battery to full discharge - it is better to leave 10-20% of the capacity in it and charge it again than to kill it all at once.

6. If possible, try to use batteries with some margin for rated current. This will extend their service life. As mentioned above, LiPo batteries are very critical to the mode of operation. When charging them, the CC-CV method is used. That is, initially the battery is charged with some fixed current (constant current - CC), while the voltage on the battery banks increases. Upon reaching the voltage of 4.20 volts on each bank, the battery is already charged to about 95%, and the charger proceeds to the second phase of the CV charge algorithm (constant voltage, constant voltage). In this case, the current is gradually reduced so that the voltage on each bank does not exceed 4.20 volts. This value is determined by the chemistry of the LiPo battery. Exceeding it is permissible no more than up to 4.25 volts, and reaching a value of 4.30 and above is fraught with explosive spontaneous combustion.

The CV charge phase in the field is negligible: it adds only the last 5% of the capacity, but takes about a third to a half of the total charge time at a 1C charge. Therefore, you can stop charging when the battery reaches the maximum voltage value, saving time.

When discharging during operation, it is unacceptable to reduce the voltage on each of the cans below 3 volts. It is enough to put a LiPo battery up to 2.5 volts per jar once, and, as a rule, it can be thrown away. After such a discharge, the battery may "swell", it loses more than half of its capacity and ceases to give the rated discharge current. For some time, the battery loses its capacity, almost completely.

Hence the problem of operating LiPo is that during charging it is necessary to control the voltage on each of the cans so as not to disable it, and during the subsequent discharge, all the banks were discharged equally, but not below the permissible minimum. A conventional charger can control the voltage on the battery as a whole, but with a large spread of voltages on the banks, it is quite possible that one of them has another 4.05 volts, and the second has 4.30. Charging sees only a total of 8.35 and continues to charge the battery up to 8.40 (4.20 * 2). In this case, the voltage on the second bank exceeds 4.30, which most likely leads to a fire. When discharging an unbalanced battery, the same problem can overdischarge a single cell, despite the fact that the total voltage is even higher than 3 volts * number of cells.

To solve this problem, a special device called a balancer is used. In the process of charging, it monitors the voltage on each of the cans and aligns them with each other. In this case, the charger will turn off the charge in time, without damaging the battery. When a balanced battery is discharged on a model, all banks are also discharged more or less evenly, and when the total voltage drops to 3 volts per bank, the regulator cut-off should work, which will prevent the battery from failing. Many modern chargers already have a built-in balancer, which you should definitely use by connecting a separate battery balancing connector along with the power one and choosing the appropriate charge mode. For devices that do not have a built-in balancer, you must purchase a separate external device.

The LiPo charge current must not exceed the battery capacity, i.e. the maximum charge current is 1C. For example, to charge a battery with a capacity of 2200 mAh, the charge current should not exceed 2.2 A. At the same time, the charge current should not be set less than 0.5C. Some chargers (Duratrax ICE) have a non-switchable timer to charge LiPo batteries for 3 hours. By setting a small current, the charger may not fully charge the battery, but turn off by a timer. There are chargers that have this timer adjustable, but it doesn't make much sense to use it for LiPo charging.

There is no point in forcibly discharging or cycling a lithium battery, since these batteries have no memory effect and must be stored in a charged state (the most optimal storage mode is 60% charge). The battery discharge current can be any, but not more than its nominal value indicated on the label, also in units of capacity C. For example, 20C on a 1000 mAh battery means that the maximum continuous discharge current is 20 * 1000 = 20000 mA = 20 A. It should be noted that that if you do not use the battery to the limit of its capabilities, then it will live a much larger number of cycles. For example, for one of the branded expensive LiPos with a rated current of 30C, the following typical data are given: when charging and discharging with currents of 1C, the manufacturer guarantees 500 cycles without significant loss of capacity. When charging with a current of 1C, but discharging with a maximum allowable current of 30C, the number of cycles will be only 50 (it will drop 10 times). This gives a good example of why it is desirable to have a battery current headroom.

In the process of charging or discharging, do not allow the battery to heat up more than 60 degrees. The place where the battery is installed on the model must be well ventilated and even ventilated. Do not wrap the battery with heat-insulating materials (foam rubber, polystyrene). If the battery does become warm, allow it to cool before using (charging or discharging).

Example of charging LiPo GE 2200 25C 22V

As an illustration of what has been said below, a typical graph of the charge of a lithium-polymer assembly of two series-connected GE 2200 25C 11.1V batteries after use is shown. The graph was obtained using an Infinity 960SR charger with an external LCB12s balancer connected to a computer.

The red line shows the charge current, the blue line shows the voltage on the battery, the colored lines show 6 voltage graphs on each of the cans of the resulting assembly.

The graph shows the following:

1. Initially, the current is set to 0.5C (1.1A), and this current charges the battery to approximately 95% of its capacity (DC phase, CC). In this case, the voltage on the battery gradually increases from about 19.8 volts to 25.2.

2. The current dip at the 10th minute of charging is caused by the charger measuring the internal resistance of the battery (an important parameter for assessing the condition of the battery).

3. After the battery reached its maximum voltage (4.2 volts per cell or 25.2 for the entire battery), the current began to decrease, and the voltage became constant (constant voltage phase, CV).

4. It is clearly seen that at the first 10% of the capacity, the voltage spread of the cans is maximum. This is one of the reasons why it is not recommended to discharge the battery by 100% - it is in the last 10% that a rapid drop in voltage occurs on banks with a large spread, and it is at this moment that the battery can be damaged.

5. It can be seen that in the first 10 minutes of the charge, the balancer almost completely equalized the voltages on the banks. Current fluctuations at the 50th minute are caused by a small spread in the parameters of the cans - again the work for the balancer, which inevitably affects the charge current supported by the device.

6. The charge is performed until the current drops to a value equal to 1/10 of the initial one. A gentle charge mode was set with a current of 1.1A, and the shutdown occurred when the current dropped below 0.11A. The values ​​of the capacity, current and voltage obtained by the battery at the end of the charge are displayed numerically. From the graph, we can conclude that a particular battery has the declared capacity (in this case, at a nominal value of 2200 mAh, it received 2190 mAh after operation. In addition, the balance of the battery cans is almost perfect, which directly indicates the quality of this brand and a particular battery, in particular.

Any beginner has a question: What is LiPo and what it is eaten with. Let's try to figure it out.

After reading it, beginners began to ask questions about LiPo, which was the reason for creating the article.

1.What is a LiPo battery?
It often happens that a person does not want to look for anything and immediately asks questions. I won't move the text. Read.
http://bit.ly/YgKh2X

Lipo acc. must be carefully chosen for the model.
Any LiPo acc. has a label. For example Turnigy 1600 mah 3S 30C where,
Turnigy - manufacturer
1600 mah - battery capacity
3S - number of cans (1 can 3.7v)
30C - current output

1C - one battery capacity. For our example, 1600 ma (or 1.6A) A is ampere
For the provided battery, we get: 30 x 1.6A = 48A
The RC system of the model that uses this acc. , should have a peak current in the electric circuit of less than 48A, preferably with a margin. (No more than 40-45A)
If this condition is not met, the battery will be killed.
An alarming sign will be its swelling. Such batteries can be returned to their original state by putting them in a refrigerator or basement / cellar; however, the functionality will be reduced. After such procedures, you need to do a couple of discharge-charge cycles.

I want to emphasize that LiPo is a dangerous thing and must be handled with care.

What not to do:

1. damage the outer shell.
2. heat.
3. strongly discharge (below 3v.)
4. charge with high currents.

2.How to charge?
To charge LiPo batteries, special chargers (chargers) are used.
It is highly recommended to use a charger with balancing capability.


Any LiPo acc. (2S and above) has 2 wires: 1) Power (red "+" and black "-")
2) Balancing.
A balancing wire is needed to evenly charge all the cans of the battery.
Modelers attach a tweeter voltmeter to the balancing wire to prevent discharge below the threshold.

LiPo batteries can be charged with 1C current. For a long life of your battery, you need to use a charge current of 0.4-0.6C. When choosing such a current, the battery will live longer (aging will progress less).
But I must indicate that there are batteries with a charge current of 2C or 5C. It will be indicated on the package.
Consider an example: Turnigy 1600 mah 3S 30C
Current 1C is 1.6A, but optimally for a battery, you can take a charge current of 1A.
The battery will be charged longer than with a current of 1.6A, but the service life will be longer.
If the charge current is more than 1C, then the battery may explode and there will be a fire.

Most advanced chargers have different LiPo charge options.
charge charge
discharge discharge
balance
storage
You need to select the number S of your battery, set the current strength - A and wait.

3.How to store?
Batteries must be stored 60% charged (3.8v per cell)
If stored at 100% charged or discharged for a long time, the battery will die/swell.
Proper storage of LiPo requires:

1. Keep away from direct sunlight
2. Temperatures from +18 to +5 are recommended (some modelers keep them in the refrigerator)
3. Store in special bag or fireproof box.
4. Put the battery in storage mode.

With improper care of LiPo, it tends to quickly "die"" (current output drops, capacity decreases)

The article was written for a group in VK RC reviews

Battery technology does not stand still and gradually Ni-Cd (nickel-cadmium) and Ni-MH (nickel-metal hydride) batteries are being replaced on the market by batteries based on lithium technology. Lithium-polymer (Li-Po) and lithium-ion (Li-ion) batteries are increasingly used in various electronic devices as a current source

Lithium- silver-white, soft and ductile metal, harder than sodium, but softer than lead. Lithium is the lightest metal in the world! Its density is 0.543 g/cm 3 . It can be processed by pressing and rolling. There are lithium deposits in Russia, Argentina, Mexico, Afghanistan, Chile, USA, Canada, Brazil, Spain, Sweden, China, Australia, Zimbabwe and Congo

Excursion into history

The first experiments on the creation of lithium batteries began in 1912, but only six decades later, in the early 70s, they were first introduced into household devices. And, I emphasize, it was just the batteries. Subsequent attempts to develop lithium batteries (rechargeable batteries) were unsuccessful due to problems associated with ensuring the safety of their operation. Lithium, the lightest of all metals, has the highest electrochemical potential and provides the highest energy density. Batteries using lithium metal electrodes are characterized by high voltage and excellent capacity. But as a result of numerous studies in the 80s, it was found that the cyclic operation (charge - discharge) of lithium batteries leads to changes in the lithium electrode, as a result of which thermal stability decreases and there is a threat of the thermal state getting out of control. When this happens, the temperature of the cell quickly approaches the melting point of lithium - and a violent reaction begins, igniting the gases released. For example, a large number of lithium batteries for mobile phones shipped to Japan in 1991 were recalled after several explosions.

Due to the inherent instability of lithium, researchers have turned their attention to non-metallic lithium batteries based on lithium ions. Having lost a little with energy density and taking some precautions when charging and discharging, they got safer so-called lithium-ion (Li-ion) batteries.

The energy density of Li-ion batteries is usually several times higher than that of standard NiCd and NiMH batteries. Thanks to the use of new active materials, this superiority is increasing every year. In addition to the large capacity, the Li-ion battery behaves similarly to nickel batteries when discharging (the shape of their discharge characteristics is similar and differs only in voltage).

Today, there are many varieties of Li-ion batteries, and you can talk for a long time about the advantages and disadvantages of one type or another, but it is impossible to distinguish them in appearance. Therefore, we note only those advantages and disadvantages that are characteristic of all types of these devices, and consider the reasons that led to the birth of lithium-polymer (Li-Po) batteries.

Li-ion battery was good for everyone, but problems with ensuring the safety of its operation and the high cost led scientists to create a lithium-polymer battery (Li-pol or Li-po).

Their main difference from Li-ion is reflected in the name and lies in the type of electrolyte used. Initially, in the 70s, a dry solid polymer electrolyte was used, similar to a plastic film and not conducting an electric current, but allowing the exchange of ions (electrically charged atoms or groups of atoms). The polymer electrolyte actually replaces the traditional porous separator impregnated with electrolyte, due to which they have a flexible plastic shell, have less weight, high current output and can be used as power batteries for devices with powerful electric motors.

This design simplifies the manufacturing process, is more secure, and allows the production of thin, free-form batteries. The minimum thickness of the element is about one millimeter, so that equipment designers are free to choose the shape, shape and size, up to incorporating it into clothing fragments.

Main advantages

• Lithium-ion and lithium-polymer batteries with the same weight surpass nickel (NiCd and Ni-MH) batteries in energy intensity
• Low self-discharge
• High voltage of a single cell (3.6-3.7V versus 1.2V-1.4 for NiCd and NiMH), which simplifies the design - often the battery consists of only one cell. Many manufacturers use in various compact electronic devices (cell phones, communicators, navigators, etc.) just such a single-cell battery
• Thickness of elements from 1 mm
• Possibility to obtain very flexible forms

Flaws

• The battery is subject to aging even if it is not used and just sits on a shelf. For obvious reasons, manufacturers are silent about this problem. The clock starts ticking from the moment the batteries are manufactured at the factory, and the decrease in capacity is the result of an increase in internal resistance, which in turn is generated by the oxidation of the electrolyte. As a result, the internal resistance will reach a level where the battery will no longer be able to deliver the stored energy, although there will be enough of it in the battery. After two or three years, it often becomes unusable.
• Higher cost than NiCd and Ni-MH batteries
• When using lithium-polymer batteries, there is always a risk of their ignition, which can happen due to contact closure, improper charging, or mechanical damage to the battery. Since the combustion temperature of lithium is very high (several thousand degrees), it can ignite nearby objects and cause a fire.

Main characteristics of Li-Po batteries

As mentioned above, lithium-polymer batteries with the same weight exceed NiCd and Ni-MH batteries by several times in terms of energy consumption. The service life of modern Li-Po batteries, as a rule, does not exceed 400-500 charge-discharge cycles. For comparison, the life of modern Ni-MH batteries with low self-discharge is 1000-1500 cycles.

Technologies for the production of lithium batteries do not stand still, and the above figures may lose their relevance at any time, because. battery manufacturers are increasing their characteristics every month through the introduction of new technological processes for their production.

Of the variety of commercially available lithium polymer batteries, two main groups can be distinguished - fast-discharge(Hi Discharge) and ordinary. They differ among themselves in the maximum discharge current - it is indicated either in amperes or in units of battery capacity, denoted by the letter "C".

Areas of application for Li-Po batteries

The use of Li-Po batteries allows you to solve two important problems - to increase the operating time of devices and reduce the weight of the battery

Ordinary Li-Po batteries are used as power sources in electronic devices with relatively low current consumption (mobile phones, communicators, laptops, etc.).

Fast Discharge Lithium polymer batteries are often referred to as " power"- such batteries are used to power devices with high current consumption. A striking example of the use of "power" Li-Po batteries are radio-controlled models with electric motors and modern hybrid cars. It is in this market segment that the main competitive struggle between various manufacturers of Li-Po batteries takes place.

The only area where so far lithium-polymer batteries are inferior to nickel ones is the area of ​​\u200b\u200bsuperhigh (40-50C) discharge currents. In terms of price, in terms of capacity, lithium-polymer batteries cost about the same as NiMH. But competitors have already appeared in this market segment - (Li-Fe), the production technology of which is developing every day.

Charging Li-Po batteries

The charge of most Li-Po batteries is carried out according to a fairly simple algorithm - from a constant voltage source of 4.20V / cell with a current limit of 1C (some models of modern power Li-Po batteries allow charging them with a current of 5C). The charge is considered complete when the current drops to 0.1-0.2C. Before switching to voltage stabilization mode at a current of 1C, the battery gains approximately 70-80% of its capacity. It takes about 1-2 hours to fully charge. The charger is subject to rather stringent requirements for the accuracy of maintaining the voltage at the end of the charge - no worse than 0.01 V / bank.
Of the chargers on the market, two main types can be distinguished - simple, non-computer chargers in the $10-40 price range, designed only for lithium batteries, and universal chargers in the $80-400 price range, designed to serve various types of batteries. batteries.

The former, as a rule, have only an LED charge indication, the number of cans and the current in them are set by jumpers or by connecting the battery to various connectors on the charger. The advantage of such chargers is their low price. The main drawback is that some of these devices are not able to correctly determine the end of the charge. They determine only the moment of transition from the current stabilization mode to the voltage stabilization mode, which is approximately 70-80% of the capacity.

The second group of chargers has much wider possibilities, as a rule, they all show the voltage, current, and capacity in mAh that the battery “accepted” during the charge, which allows you to more accurately determine how charged the battery is. When using the charger, the most important thing is to correctly set the required number of cans in the battery and the charge current, which is usually 1C, on the charger.

Li-Po battery handling and precautions

It is safe to say that lithium-polymer batteries are the most “gentle” of the existing ones, i.e. require the observance of a few simple rules. We list them in descending order of danger:

1. Recharge battery - charge up to a voltage exceeding 4.20V per cell
2. Battery short circuit
3. Discharge with currents exceeding the load capacity or leading to heating of the Li-Po battery over 60 ° C
4. Discharge below 3V per cell
5. Battery heating above 60ºС
6. Battery depressurization
7. Storage in a discharged state

Failure to comply with the first three points leads to a fire, all the rest - to a complete or partial loss of capacity

From all that has been said, the following conclusions can be drawn:

• To avoid a fire, you must have a normal charger and correctly set the number of charged cans on it
• It is also necessary to use connectors that exclude the possibility of a short circuit of the battery and control the current consumed by the device in which the Li-Po battery is installed.
• You need to be sure that your electronic device in which the battery is installed does not overheat. At +70ºС, a "chain reaction" begins in the battery, turning the energy stored by it into heat, the battery literally spreads, setting fire to everything that can burn
• If you close an almost discharged battery, then there will be no fire, it will quietly and peacefully “die” due to overdischarge
• Watch the voltage at the end of the battery discharge and be sure to turn it off after work
• Depressurization is also the reason for the failure of lithium batteries. Air must not get inside the element. This can happen when the outer protective bag is damaged (the battery is sealed in a bag like a heat shrink tube) as a result of a blow, or if it is damaged by a sharp object, or if the battery terminal is overheated during soldering. Conclusion - do not drop from a great height and solder carefully
• According to the manufacturers' recommendations, batteries should be stored in a 50-70% charged state, preferably in a cool place, at a temperature not exceeding 30°C. Storage in a discharged state adversely affects the service life. Like all batteries, lithium polymer batteries have a small self-discharge.

Assembling Li-Po batteries

To obtain batteries with high current output or high capacity, batteries are connected in parallel. If you buy a ready-made battery, then by marking you can find out how many cans are in it and how they are connected. The letter P (parallel) after the number indicates the number of cans connected in parallel, and S (serial) - in series. For example, "Kokam 1500 3S2P" refers to a battery connected in series of three pairs of batteries, and each pair is formed by two 1500 mAh batteries connected in parallel, i.e. the battery capacity will be 3000 mAh (when connected in parallel, the capacity increases), and the voltage is 3.7V x 3 = 11.1V.

If you buy batteries separately, then before connecting them to a battery, you need to equalize their potentials, especially for the parallel connection option, since in this case one bank will start charging another and the charging current may exceed 1C. It is advisable to discharge all purchased banks before connecting to 3V with a current of about 0.1-0.2C. The voltage must be controlled with a digital voltmeter with an accuracy of at least 0.5%. This will ensure reliable battery performance in the future.

It is also desirable to carry out potential equalization (balancing) even on already assembled branded batteries before their first charge, since many companies that assemble elements into a battery do not balance them before assembly.

Due to the drop in capacity as a result of operation, in no case should new banks be added sequentially to the old ones - the battery will be unbalanced in this case.

Of course, it is also impossible to combine batteries of different, even similar capacities into a battery - for example, 1800 and 2000 mAh, and also use batteries from different manufacturers in one battery, since different internal resistance will lead to battery imbalance.

When soldering, be careful not to overheat the leads - this can break the seal and permanently "kill" the battery that has not yet worked. Some Li-Po batteries come with pieces of a textolite printed circuit board already soldered to the terminals for easy wiring. At the same time, extra weight is added - about 1 g per element, but it is possible to heat places for soldering wires much longer - fiberglass does not conduct heat well. Wires with connectors should be fixed to the battery case, at least with adhesive tape, so as not to accidentally tear them off when repeatedly connected to the charger

The nuances of using Li-Po batteries

I will give a few more useful examples arising from what was said earlier, but not obvious at first glance ...

During the long operation of the battery, its elements become unbalanced due to the initial small spread of capacities - some banks “age” earlier than others and lose their capacity faster. With more cans in the battery, the process goes faster. This leads to the following rule: it is necessary to control the capacity of each battery cell.

If a battery is found in the assembly, the capacity of which differs from other cells by more than 15-20%, it is recommended to refuse to use the entire assembly, or solder the battery with a smaller number of cells from the remaining batteries.

Modern chargers have built-in balancers (balancer), which allow you to charge all the elements in the battery separately under strict control. If the charger is not equipped with a balancer, then it must be purchased separately and it is advisable to charge the batteries using it.

An external balancer is a small board connected to each bank containing load resistors, a control circuit and an LED indicating that the voltage on this bank has reached 4.17-4.19V. When the voltage on a separate element exceeds the threshold of 4.17V, the balancer closes part of the current “on itself”, preventing the voltage from exceeding the critical threshold.

It should be added that the balancer does not save from overdischarging some cans in an unbalanced battery, it only serves to protect against damage to the cells during charging and a means of identifying "bad" cells in the battery.

The above applies to batteries made up of three cells or more, for two-cell batteries, balancers, as a rule, are not used.

According to numerous reviews, the discharge of lithium batteries to a voltage of 2.7-2.8V has a more detrimental effect on capacity than, for example, overcharging to a voltage of 4.4V. It is especially harmful to store the battery in an over-discharged state.

There is an opinion that lithium-polymer batteries cannot be operated at low temperatures. Indeed, the technical specifications for the batteries indicate an operating range of 0-50 ° C (at 0 ° C, 80% of the battery capacity is preserved). But nevertheless, it is possible to use Li-Po batteries at low temperatures, about -10 ... -15 ° С. The fact is that you do not need to freeze the battery before use - put it in your pocket, where it is warm. And in the process of use, the internal generation of heat in the battery turns out to be a useful property at the moment, preventing the battery from freezing. Of course, the output of the battery will be somewhat lower than at normal temperature.

Conclusion

Given the pace of technological progress in the field of electrochemistry, it can be assumed that the future belongs to lithium energy storage technologies if fuel cells do not catch up with them. Wait and see…

The article uses materials from articles by Sergei Potupchik and Vladimir Vasiliev

Airsoft guns

There have been a lot of questions about LiPo batteries lately. I decided to write an article about charging, using and selecting LiPo batteries.

For example, consider the battery ZIPPY Flightmax 1000mAh 2S1P 20C

Anything up to 1000 is the manufacturer's name or trademark.

1000mAh is the capacity of the battery.

2S1P– 2S is the number of batteries in the assembly. Each battery has a voltage of about 3.7 volts, so the voltage of such a battery is 7.4 volts. 1P is the number of builds. That is, if you take 2 identical batteries, connect them with electrical tape and solder the power wires in parallel (plus with plus, and minus with minus), then we will get a doubling of the capacity, such a battery is designated 1000 2S2P and actually equals 2000 2S1P in operation. Usually only single assemblies are used, so 1P is not spoken or written.

20C- the maximum discharge current, measured in battery capacities.

To calculate how many LiPo can deliver amps when loaded with an engine, you need to multiply the Capacitance by the number of C and divide by 1000 (since the capacitance is indicated in milliamps / hours). The maximum current of this battery will be 20 amps. For 2200 20С - 44 amperes, 1200 30С = 36 amperes and so on.

Charging LiPo batteries

LiPo batteries are charged at 1C (unless otherwise indicated on the battery itself, they have recently appeared with the ability to charge with a current of 2 and 5C). The standard charging current of the battery in question is 1 Amp. For a 2200 battery, it will be 2.2 amps, and so on.

The computerized charger balances the battery (equalizing the voltage on each cell of the battery) during charging. Although it is possible to charge 2S batteries without connecting a balance cable (white connector in the photo), I highly recommend always connect the balancing plug! 3S and large assemblies only charge with the balance wire connected! If you don't connect and one of the cans draws more than 4.4 volts, then an unforgettable fireworks display awaits you!

You can protect yourself and charge in special packages - they are non-combustible and are specifically designed to reduce harm in the event of a LiPo battery fire.

We continue the story about charging LiPo batteries.

Usually, about 90% of the capacity is quickly poured into the battery, and then recharging begins with balancing the cans. More charged and approached the limit are shunted and the charge goes to the remaining banks. That is why it can charge a pair of 3S batteries as one 6S.

The battery charges to 4.2 volts per cell (usually a few millivolts less).

Storage mode

On a “smart” charger, you can put LiPo into storage mode, while the battery will recharge / recharge up to 3.85V per cell. Fully charged batteries will die if stored for more than 2 months (maybe less). Verified by personal experience. They say that they are completely discharged too, but for a longer period.

I store batteries in a plastic case. It's comfortable. A friend keeps and wears in the field in the aforementioned packages. LiPo is an ordinary battery and if you do not close the contacts and do not break through it, then it will not bring any trouble during storage and transportation.

Operation LiPo

Discharging a LiPo battery below 3 volts per cell is not recommended - it can die. You can use sound indicators, but there is a chance that it will squeak at the most inopportune moment and you will be bombarded with balls from head to toe, like the last losharu! The sound buzzer is connected to the balancing connector and when it squeaks, it's time to change or take out the secondary.

When the motor draws more current than the battery can supply, LiPo tends to swell and die. So this must be strictly monitored! Use wattmeters for control.

During operation, there is one more nuance - our battery is 1000mAh 20C. The idea is to give 20A. Motors usually allow you to exceed the recommended currents by 20%, however, I exceeded by 80% 🙂

In reality, the batteries do not hold the maximum current output very well. For example, my 2200 20C gives a current of 44A in just 2-3 minutes, then there is a voltage drop, although according to calculations it is obliged to give at least 5 minutes.

So when choosing a LiPo battery, we look at the maximum current declared for the selected engine and add a reserve. So for a motor that eats 8-12A, our 1000mAh 20C is quite suitable, but for 16-18A I would choose either with a higher current output, for example 25-30C, or take a larger capacity, for example 1600 20C.

Lithium polymer (LiPo) batteries
Instructions for use and safety

Read and follow these instructions carefully before using the elements. Incorrect use of cells may result in significant heat generation, fire, explosion, damage or loss of cell capacity.

General instructions

Lithium polymer batteries (LiPo batteries for short) require special care. This is true for charging and discharging as well as storage and other operations. The following special instructions must be observed:

Improper handling can result in explosions, fire, smoke emission and danger of poisoning. In addition, failure to follow instructions and cautions may result in loss of performance and other disadvantages.

The battery capacity decreases with each charge/discharge. Storage at too high or too low temperatures can also lead to a gradual decrease in their capacity. In the design of the model, batteries after 50 cycles, subject to charging and discharging instructions, still provide 50-80% of the capacity of a new battery, which is achieved due to high discharge currents and motor induction currents. Battery packs must not be connected in series or in parallel, as the capacities of the battery cells may be too different. Therefore, the battery packs supplied by us have been specially selected.

Special Instructions for Charging LiPo Batteries

To charge LiPo batteries, use only approved chargers with their associated charging cables. Any operation on the charger or charging cable can have serious consequences. When using a charging cable with a protection circuit, a mandatory and complete control over each individual element of the battery pack is carried out. The maximum charging capacity should be limited to 1.05 times the battery capacity.

P Example: For a 1800 mAh battery: The charging capacity is 1890 mAh.

Number of elements in the assembly	1S	2S	3S
Rated voltage, Volt			11,1
Rated capacity C, mAh	1800	1800	1800
Max. Charging voltage, Volt			12,6
Min. Discharge voltage, Volt
Permissible charging current 1C, mAh	1800	1800	1800
Balancing current, mAh	1800	1800	1800

To charge and discharge a LiPo battery, use only chargers and dischargers that are specifically designed to work with this type of battery. Make sure the correct number of cells is set, as well as the correct charge end voltage and discharge end voltage. When doing this, follow the instruction manual for your charger/discharger.

Additional Handling Instructions

The battery to be charged must be placed on a non-breakable, heat-resistant, non-conductive support during the charging process! Flammable and flammable items should also be kept away from the charging area.

LiPo batteries connected in series can only be charged together in a block if the voltage of the individual cells deviates by no more than 0.05 V. If the voltage deviation is more than 0.05 V, then the voltage should be equalized as accurately as possible by charging or discharging each battery cell.

Under these conditions, a LiPo battery can be charged with a maximum of 1C (the value of 1C corresponds to the capacity of one cell) of the charging current. Starting from max. voltage of 4.2 V per cell, you should continue charging at a constant voltage of 4.2 V until the charging current is less than 0.1-0.2 A.

Voltages above 4.25 V per cell should be avoided as otherwise it may be permanently damaged. To prevent overcharging, you should set the charge off value to 4.1-4.5V per cell, which will increase battery life.

After each charging process, it should be checked whether the permissible voltage of 4.2 V of individual cells is exceeded. Should be the same voltage. If the voltage of individual battery cells deviates by more than 0.05 V, then the voltage should be equalized by charging or discharging each cell individually. To prevent overcharging, after using the unit for a long time, they should be charged individually on a regular basis.

Always observe the correct polarity when charging the battery. If the polarity is reversed during charging, abnormal chemical reactions occur and the battery becomes unusable. This may result in cracking, smoke or fire. The allowable temperature range for charging and storing LiPo batteries is 0-50°C.

Storage: LiPo batteries should be stored charged at 20% of their nominal capacity. If the voltage of the battery cells drops below 3 V, then they must be recharged. Deep discharge and storage in a discharged state (cell voltage less than 3 V) make the battery unusable.

Special instructions for discharging a LiPo battery:

Discharging below 3 volts per cell causes permanent damage to them, so this situation must be avoided. If the individual cells differ in charge level, then the regulator shutdown due to low voltage will occur too late, as a result of which the individual cells may be too discharged.

The battery temperature during discharging should not rise above 70°C. Otherwise, you should take care of better cooling or reduce the discharge current.

battery shell

Film-laminated aluminum foil can be easily damaged by sharp objects such as needles, knives, nails, motor contacts, etc. Due to damage to the film, the battery becomes unusable. Therefore, the battery should be inserted into the model in such a way that the battery cannot be deformed even if the model falls or collides with other objects. If the battery is shorted, it may catch fire.

Temperatures above 70°C can also damage the case, making it leaky. This leads to the loss of electrolyte, the battery becomes unusable and must be disposed of.

mechanical shock

LiPo batteries do not have the same mechanical stability as batteries in metal cases. Therefore, avoid mechanical shocks that may be caused by falling, bumping, bending, etc. Never cut, tear, deform, or drill into the laminated aluminum foil, or bend or bend the LiPo battery. Do not put pressure on the battery or contacts.

Contact handling:

Contacts are not as strong as in other batteries. This applies especially to the aluminum positive contact. Contacts break off easily. Due to heat transfer, the outer terminals of the contacts must not be soldered directly.

Cell connection

Direct soldering of battery cells to each other is not allowed.

When soldering directly, high temperatures can damage battery components such as the separator or insulator. Connections to the battery may only be made industrially by means of spot welding. If the cable is missing or broken, professional repair is required by the manufacturer or distributor.

General Precautions When Using Batteries

Do not expose batteries to fire or incinerate them.

Keep water and other liquids away from the elements.

Do not overheat the elements. With strong heating (over 90 ° C), the insulator may melt, the structure of the element. This may result in significant heat generation, fire or explosion.

Batteries must not be exposed to microwaves or pressure. This can cause smoke, fire and more serious consequences.

Batteries should be stored and charged on a stand made of non-flammable, heat-resistant and non-conductive materials.

Observe the polarity when connecting the elements to the charger or consumer. Reverse polarity charging may cause fire or explosion.

Do not short-circuit cell or battery leads. Large short circuit currents inevitably lead to the release of a significant amount of heat, loss of electrolyte, gas formation, fire or explosion.

Protect the elements from shock and damage, do not drop them. Strong mechanical influences can disrupt the internal structure. Deformations can cause a short circuit, which can lead to significant heat generation, fire or explosion.

Be careful when soldering elements. Overheating of the terminals may cause the battery jacket to melt, which may result in significant heat generation, fire, or explosion.

Do not disassemble or modify the elements. Disassembling the battery can cause internal short circuits. This can result in gas, fire, explosions or other problems.

After use, disconnect the battery from the consumer to avoid deep discharge.

Keep away from children. If the battery is swallowed, contact a doctor or an ambulance immediately. Incorrect use is dangerous.

When charging batteries

Do not use chargers not approved by the manufacturer. Follow the charging modes recommended by the cell manufacturer. Failure to comply with the specified modes (temperature, voltage or current, incorrect functioning of the shutdown devices) can lead to the release of a significant amount of heat, fire or explosion.

Carry out charging under constant supervision. Never leave rechargeable batteries unattended.

Do not connect the battery directly to a power source (accumulator, power supply, etc.). High voltage causes excessive charging current, which can lead to significant heat generation, fire or explosion.

After the charging time specified by the manufacturer, stop the charging process, even if it is not completed.

The batteries built into the device must be removed from the device if they are not currently in use, unused devices must be turned off in a timely manner to prevent deep discharges. Keep the batteries charged in a timely manner. Deeply discharged LiPo batteries are defective and should not be used again.

Do not charge the battery near heat sources or in a car. Overheating may cause electrolyte leakage, excessive heat generation, fire or explosion.

Do not use or charge Lithium Polymer cells with dry cells or batteries of any other type or capacity. In such cases, a deep discharge or an overcharge of the cells is likely. These factors cause undesirable chemical reactions in the elements, which can lead to the release of a significant amount of heat, fire or explosion.

If you notice a change in the shape, color of the element, an unfamiliar smell, or if you find the element heating, immediately disconnect it from the consumer or charger and avoid using this element in the future.

If the cell seal is compromised (case integrity damage, electrolyte leakage, or odor found), immediately remove the cell from any source of open flame. The electrolyte is flammable.

The electrolytes contained in LiPo batteries or electrolyte vapors are harmful to health. Never allow direct contact with electrolytes.

If electrolyte comes into contact with the skin, eyes, or other parts of the body, wash immediately with plenty of clean water, then seek medical attention. If help is not provided in a timely manner, prolonged exposure to the electrolyte can cause serious harm.

Batteries that are damaged or worn out are classified as special waste and must be disposed of properly.