Learn how to convert your electric screwdriver to lithium ion batteries with your own hands
The electric screwdriver is so closely embedded in the life of modern man that no repair or construction work at home and at work can do without it. The main convenience of the tool is its mobility, which is ensured by a removable self-contained battery. That’s why the device in question and got the name “cordless electric screwdriver”. Often in operation there is a question of how to remake the battery of an electric screwdriver, as nickel-cadmium batteries have a big disadvantage compared to lithium batteries. it is a low service life. To avoid buying a new power tool with a lithium battery, you can upgrade your old battery by replacing the nickel-cadmium banks in it.
The portability of the electric screwdriver is provided by using an independent power source. A rechargeable battery acts as such source, whose operating principle is similar to that of an ordinary watch or remote control battery. Only the battery for power tools has a voltage ten times greater than that of an ordinary button cell battery.
The battery powers the electric screwdriver motor. As the electric motor armature rotates, torque is transmitted to the gearbox. Reducer reduces or increases the rotation speed (depending on the set mode) of the working organ. the chuck in which attachments are fixed. The independent power source as a battery in an electric screwdriver is a key element, without which the operation of the device would simply not be possible.
Owners of inexpensive screwdrivers are often faced with the situation of a rapidly discharging battery. The reason for this is the material used to manufacture the independent power source. There are three main types of batteries for electric screwdrivers:
- Nickel-cadmium ones are the most basic, inexpensive and short-lived. Another disadvantage of this material is a small charge reserve
- Nickel-metal hydride. an improved modification of cadmium batteries, which have increased resistance to frequent charges and discharges (but they also discharge quickly). Exposure to low temperatures negatively affects the duration of operation of the source
- Lithium-ion batteries. this is a new era of batteries, which not only hold a long charge (slow consumption due to high capacity), but can also serve for at least 10 years
Often owners only realize after buying an electric screwdriver that comes with a nickel-cadmium battery that they “should have chosen a power tool with a lithium battery”. The reason for buying a power tool with a nickel-cadmium source is also easy to explain, because with such a battery the device costs several times cheaper. If you don’t believe me, you can compare on screwdrivers at Cylinder online store.
Nickel cadmium and metal hydride. why you need to replace them
One of the very first batteries to be used in power tools were nickel-hydride sources. The merits of these devices include optimal capacity reserves and low tank heating rates when compared to hydride devices. In addition, such sources are inexpensive, yet effectively cope with their main task when properly applied.
The advantages of nickel cadmium devices include:
- Lower risk of overheating than hydride batteries
- Nickel-cadmium sources are contained inside a metal housing that provides a high degree of stability and tightness
- If properly operated, the nickel hydride will last at least 3-5 years, but precisely because the device often has to be used in extreme conditions, the life of the battery decreases sharply from the first day of purchase
- Low cost, which makes such devices in demand
- Not afraid of deep discharge
To extend the service life of the battery, so as not to ask yourself how to convert the battery of an electric screwdriver to lithium, it is necessary to follow the simple instructions for the use of Ni-Cd batteries:
- It is possible and necessary to work with the tool until the battery is completely discharged
- It is necessary to charge the source until its capacity is completely replenished
- Unlike lithium batteries, it is better to store cadmium batteries in a discharged state
- The “memory effect” is a disadvantage, but it can easily be eliminated by repeating three “charge-discharge” cycles
Hydride appeared after the cadmium ones, but they have not gained much popularity, as they discharge quickly, and are not suitable for powerful models of screwdrivers. Hydride batteries have no “memory effect” and are less harmful to the environment than cadmium batteries. If your battery, which consists of cadmium or hydride sources, sooner or later it will be necessary to replace it. Buying a new battery for an electric screwdriver of a little-known brand or an outdated model is almost impossible, so it becomes necessary to upgrade the old one. From an old cadmium battery can be made even better, but this requires understanding how to remake the battery electric screwdriver.
Battery varieties for an electric screwdriver
Almost all modern models of electric screwdriver have the same device of the battery unit. the elements in series connected in a single chain. Their shape, dimensions and rating are always the same. Together, they create the final voltage of the appliance. The difference between them is observed only in the capacity. This circumstance makes it easy to pick up and replace such batteries.
As a rule, there are 3 main varieties of batteries:
Each unit is rated at 1.2 volts. Their main advantages are expressed in the following:
- Availability due to prevalence and low price.
- Resistant to negative ambient temperatures.
- Retains performance when stored in a discharged state.
Disadvantages manifest themselves in low capacity, as well as a number of factors such as:
In addition, due to the toxicity of the production cycle, this type of battery is produced by manufacturers in third-world countries, which itself can manifest itself in a factory defect and low quality.
Batteries of this modification deliver a voltage of 1.2 volt. Many people prefer them as an alternative to failed units when you need to repair the battery for an electric screwdriver. This is primarily due to the high quality, as the production line for the trimmer does not pollute the environment, and therefore the technology is widely used in developed countries by well-known manufacturers.
In addition, they have the following advantages
- Minimal memory effect.
- Low self-discharge coefficient.
- Higher capacity compared to the above variety.
- Maximum operating range of “charge-discharge” cycles.
The disadvantages are the high cost, the impossibility of use at low temperatures and the reduced performance in the case of prolonged storage in a discharged state.
Batteries of this variety are rated at 3.6V. The main advantages are
- High capacity.
- Several times the range of operating cycles compared to other modifications.
- No memory effect.
- Low self-discharge.
- Possibility of reducing the weight of the battery pack. due to the need for fewer cells in the circuit due to their greater potential and capacity.
The disadvantages are expressed by the maximum price and limited shelf life. Batteries lose most of their capacity after just three years because of the chemical degradation of the filler.
Please note! The main cause of screwdriver failure is precisely the failure of the battery, and more precisely. the loss of rating or capacity of its individual elements. Thermistor failure, contact interruption or other causes are extremely rare.
Since a power supply is a chain of elements connected in series, it is necessary to determine which particular member has failed in order to replace it in order to restore the battery performance of an electric screwdriver. As one faulty link de-energizes the whole chain.
For this purpose, the following algorithm of actions is applied:
- The battery is placed in the charger until it receives a charging signal.
- Dismantle the battery pack.
- Voltmeter is used to measure voltage of each battery.
- Marks are put on all cells, which nominal value is lower than the normally working ones. For example, the nickel-cadmium ones give out 1.1 or 1.0 volt instead of the 1.2 volt that they should.
- The unit is then reassembled and turned on until the motor power is noticeably reduced.
- After that, disassembly is repeated and the voltage of all cells is measured.
Banks that have a nominal loss of 0.4 volts or more compared to normal cells are not suitable for further use and must be replaced.
The battery for an electric screwdriver consists of a chain of cells connected in series Source acums.ru
Tip:! An alternative way to create a load before testing the battery is to connect a light bulb of the appropriate rating. When the bulb begins to fade, the battery cells can be checked for differences in rating.
Replacing the old Ni-Mh battery of an electric screwdriver with Li-Ion cells
Detailed description of the procedure for replacing the Ni-Mh cells in an old electric screwdriver battery with Li-Ion cells. Particular attention is paid to the process of selecting components.
“How much will it cost to replace the old nickel batteries with lithium-ion ones in my electric screwdriver?”.is probably one of the most popular questions we get from our customers. And indeed, the problem is quite common. Many people have an old cordless electric screwdriver (wrench, peorator, jigsaw, grass trimmer, etc.д.The first and the foremost one is the problem which is quite widespread: the old batteries are out of order and there is no possibility to buy new ones as they may be taken off sale or you just do not want to spend money on a known outdated technology, but you want to immediately replace the Ni-Mh batteries with Li-Ion and give the often expensive and high-quality power tool a second life.
There are indeed many reasons for this desire:. The first, and the main one, is that Li-Ion batteries have a much higher electrical density than Ni-Mh batteries. Simply put, for the same weight, a Li-Ion battery will have a higher electrical capacity than a Ni-Mh. Accordingly, by installing the Li-Ion batteries into the old case, we get a much longer working time of the tool.
But there are enough stopping factors to accomplish such an undertaking:. Because of technological restrictions Li-Ion batteries cannot be charged over 4.25-4.35V and discharged below 2.5-2.7V (it is specified in the technical specification for each particular battery). If these values are exceeded, you can damage the battery and put it out of service. To protect the Li-Ion battery, special charge-discharge controllers are used, which keep the voltage on the Li-Ion cell within the permitted limits. Т.The voltage of Li-Ion batteries is always a multiple of 3.7V (3.6V), while Ni-Mh batteries are a multiple of 1.2V. This is due to the nominal voltage (the amount of voltage that holds on the Li-Ion battery long enough in the middle of the volt-ampere characteristic of the discharge curve) on a single cell. For Li-Ion batteries this voltage is 3.7V, for Ni-Mh. 1,2В. So you will never be able to assemble a 12v battery from Li-Ion batteries. In nominal, it can be 11.1V (3 in series) or 14.8V (4 in series). over, the voltage of the Li-Ion cell changes during operation from fully charged, 4.25V to fully discharged.2,5В. Thus the voltage of 3S (3.5V). 3 connections in series) of the battery pack will change during operation from 12.6V (4.2×3) to 7.5В (2.5х3). For a 4S battery, from 16.8V to 10V, the Li-Ion battery 18650, and 99 percent of all Li-Ion batteries consist of 18650 cells, has a different size than the Ni-Mh cell. The 18650 cell size is 18 mm in diameter and 65 mm high. It is important to “estimate” how many Li-Ion cells will fit into your case. For a 11.1V battery you need a multiple of 3 Li-ion cells. For a 14.8V battery. four. This should leave room for the charge-discharge controller and patch leads The charger for Li-Ion batteries is different from the charger for Ni-Mh batteries. For the sake of fairness, it should be noted that chargers supplied with many screwdrivers are universal chargers and can charge both NI-Cd, Ni-Mh and Li-ion batteries. Make sure your charger has this capability Cost of Li-ion batteries. which, compared to Ni-Mh batteries, can vary by several times.
If all of the above does not scare you, then consider an example of the manufacturing process of the Li-Ion battery to replace our existing Ni-Mh battery from the wrench DeWALT DC840.
This impact wrench comes with two 12V Ni-Mh batteries with a capacity of 2.6Ah.
To begin, we will determine the nominal voltage for our Li-Ion battery pack.
The choice is between a 3S Li-ion battery with a voltage range of 12.6V. 7.5V and 4S Li-Ion battery with a voltage range of 16.8V. 10В. We choose the second option because: a) the voltage of the battery drops fairly quickly from maximum to nominal, ie.е. from 16.8V to 14.8V and for the electric motor, which in fact is the nutrunner, exceeding 2.8V is not critical. b) the minimum voltage of 3S Li-Ion battery will be 7.5V, which is extremely low for normal operation of power tools. And the efficiency of 4S battery in this case will be higher than the efficiency of 3S Li-Ion battery. c) By installing 4 Li-ion cells we increase the electrical capacity of our battery.
So, we have understood the first point: we make a 4S (14,8V) Li-Ion battery.
Second. Deciding on the choice of Li-ion cells.
For this we have to determine the limiting factors. In the case of making a Li-Ion battery for power tools, the main limitation is the maximum load current. Now there are Li-Ion batteries with allowable nominal (continuous) load current of 20-25A. Impulse (short-term, up to 1-2 seconds) load current values can reach 30-35A. At the same time you will not break the structure of the battery.
Our old Ni-Mh battery case can comfortably hold up to 6 Li-Ion 18650 cells. Accordingly, we can not assemble 4S2P (4 cells in series and 2 in parallel) Li-Ion battery, which will need 8 cells and should fall within 4 cells. Naturally, in this case, each of the cells must “hold” a single value of maximum load current over the whole range of the power tool’s operating modes.
If you have no desire to solder or make your own spot-welding machine from microwave guts, then you can be helped by this tool. Despite its extremely compact size, it works perfectly and can be a great help. Especially in a situation where you need to cook somewhere where it’s not convenient to drag a full unit.
If you are not interested in buying ready made battery packs, then you will definitely need a strip to connect the batteries. Of course you can buy it locally as well. But if you are still waiting for the same BMS board from aliexpress, it makes sense to order there everything else and save time on shopping.
CC/CV charging module
And this CC\CV module is for those who want to convert their electric screwdriver to lithium. The old charger won’t recharge and you need a small unit. If you have a multimeter, you can configure it. If it’s not a problem to spend a couple of bucks then you can get the best possible display of everything from voltage to current and buy a version with a display.
Battery protection and redesign of the battery controller.
With the batteries disassembled, we continue our conversion of the battery of an electric screwdriver for Li-ion.
Lithium needs a protection controller. Which will protect the battery banks from overcurrent, overdischarge, overcharging, as well as balance the banks when charging.
From those that I tried on the price-quality ratio, I liked the following controller.
Works great. Can handle the load. But there are some disadvantages. Protection is not removed automatically. To remove it you need to apply voltage to the battery or just put it on charge for a couple of seconds.
The second flaw in some screwdrivers can trigger protection when the trigger of an electric screwdriver is pulled sharply, and in general it is not set up for our banks (which can easily handle currents and larger), but based on the datasheet on the key transistors (which are also designed for a larger current) of the battery protection controller it can be loaded.
Both deficiencies I corrected as follows.
Revision of the controller of lithium batteries. On the picture of the board we see two smd resistors labeled R010. They’re rated at 0.01 ohm each. They set the current of the load that will trigger the protection.
I added the same type of resistor 0.01 Ohm resistor on my battery controller. the circuit. You can also add a film capacitor to it, just useful so that when you pull the trigger suddenly, the protection will not work.
The upper part of the circuit is responsible for the “Power” mode. When the position is turned on the transistor switches do not work at all and there is no load on them. But so are the protections. Therefore, it is better not to use this mode.
A 15 amp fuse in this mode provides current protection. I put them to my liking. A bigger diode. I have two 6A pulse diodes in parallel (12A together).
You can connect a small digital voltmeter like this to keep track of the discharge control.
I replaced the voltmeter with a home-built discharge indicator tuned to 12 volts. Its triggering coincides with triggering of the protection board during normal operation.
Also for clarity, in parallel to the discharge indicator (on the diagram it is a voltmeter) connected a LED through a 2Kohm resistor to immediately see when the “Power” mode is on.
To work with an electric screwdriver, I practically do not use the “Power” mode, but it is necessary to remove the triggered protection. Just switch back and forth and you can go on spinning.
This is how I got the switch to the “Power” mode. It is also used to reset the protection.
At the back of the circuit are two indicators. A red LED indicates that the mode “Power” is on. The yellow light comes on when the power mode is turned on and the battery is down to 12 volts.
Also added a socket. USB with battery voltage. The main thing that no one by mistake did not put the phone to recharge:) I use it at the construction site to listen to the adapted receiver and LED lamp.
Been testing the new lithium battery conversion for a month now, now I like it. The battery will not run down for a long time. The screwdriver can easily handle heavy loads.
There’s one more thing left to do. Fast charging, like the top models:)
How to Rebuild and Assemble?
Often the craftsman already has an old cordless electric screwdriver that suits him completely. But the device is equipped with outdated nickel-cadmium batteries. Since the battery pack has to be replaced anyway, you want to replace the old battery with something newer. Not only will it provide more comfortable operation, but it also eliminates the need to search the market for batteries of an outdated model.
The easiest thing that comes to mind is to assemble in the housing of the old battery power unit from an electronic transformer. Now it will be possible to use an electric screwdriver, connecting it to a household power grid.
14-volt models.4 volt can be connected to car batteries. If you assemble the adapter-extender from the casing of the old battery with terminals or the cigarette lighter plug, you get an indispensable device for the garage or work “in the field”.
If we are converting an old battery into lithium, we can take into account the fact that lithium cells of the 18650 standard are extremely widespread on the market. So we can make electric screwdriver batteries from readily available parts
over, the prevalence of the 18650 standard allows you to choose batteries from any manufacturer.
It is not difficult to open the case of the old battery pack and remove the old stuffing from it
It is important not to forget to mark on the housing contact to which previously was connected “plus” the old battery assembly
Depending on the voltage for which the old battery was designed, you need to select the number of lithium cells connected in series. The standard voltage of a lithium cell is exactly three times that of a nickel cell (3.6V instead of 1.2 В). Thus, each “lithium” replaces three “nickels” connected in series.
Envisioning a battery design in which three lithium cells are strung together one after the other, you can get a battery with a voltage of 10 volts.8 volts. You can find such batteries among nickel batteries, but not very often. If you connect four lithium cells in a daisy chain, you get 14.4 volt. This allows you to replace the nickel battery with both a 12 volt and a 14.4 volt is a very common standard for nickel-cadmium and nickel-metal hydride batteries. It all depends on the specific model of electric screwdriver.
Once you have determined the number of stages in series you will probably find that there is still room in the old case. This will allow two cells to be connected in parallel in each stage, doubling the capacity of the battery. To connect lithium batteries to each other, nickel tape is used in production. Tape strips are connected to each other and to the lithium cells by contact welding. But soldering is okay in the home.
Be very careful when soldering lithium parts. Clean the joint thoroughly beforehand and apply good flux. Soldering is very quick, with a well heated soldering iron of sufficiently high power.
Soldering itself is done by quickly and surely heating the connection point between the lead and the lithium element. To avoid dangerous overheating of the element, the duration of soldering must not exceed three to five seconds.
The good thing is that electronic control and balancing modules are now available at fairly low prices. Choose the right solution for your application. Basically such controllers differ from each other by the number of “steps” connected in series, the voltage between which is to be equalized (balanced). In addition, they differ in the allowable load current and the way the temperature is controlled.
In any case, you can’t charge the homemade lithium battery with the old nickel battery charger now. They have fundamentally different charging algorithms and reference voltages. A specialized charger is needed.
Choose a battery assembly diagram by capacity, voltage and available space
Depending on the voltage required for power, determine how many 18650 batteries for an electric screwdriver must be connected in series. Dependence of the number of batteries on the voltage:
If space allows, you can connect an equal number of batteries in parallel to the existing batteries to increase the capacity by half.
Which BMS board is needed and how to connect it
Lithium 18650 batteries are afraid of overcharging and deep discharging. No synchronized cell operation can be guaranteed when cells are connected in series. If one bank will have a lower capacity, then when charging it will replenish the energy faster than the others, and further charging will overcharge. A smaller capacity battery will discharge faster than the others in operation, which can lead to a deep discharge.
All these problems can be solved by a protection board with balancing. BMS boards:
- Protect against short circuits;
- are recovered after the protection is triggered;
- monitor the voltage of each bank and disconnect the load when at least one of the cells is completely discharged (deep discharge protection);
- Perform balancing (overcharge protection).
BMS boards for electric screwdriver must withstand a maximum peak current of at least 30A. In addition, the choice should be guided by the number of banks connected in series. For an electric screwdriver for 12 V requires 3 batteries, choose a board 3S. If you need 14v power supply, buy 4S, and for 18v buy 5S.
How to connect 2, 3 or 4 banks in series with a BMS board is shown in the picture.
You can also use a mixed, series-parallel connection. In this case connect the same number of batteries in parallel to the series connected banks.
The advantages of the second option
The second option is more suitable, because the voltage in the battery drops quite quickly from the maximum to the minimum (from 16.8 to 14.8 V). For an electric motor, which, in fact, an electric screwdriver is not, an excess of 3.5.8 V is not critical.
The 3S-Li-Ion modification has the lowest voltage. It is equal to 7.5 V, which is insufficient for the production activity of an electric device. By assembling four configurations, we increase the electrical capacity of the battery.
The technology of replacing Ni-Cd with Li-ion in an electric screwdriver
Lithium cells are notable for their durability, so many screwdriver owners think about replacing nickel-cadmium products with them.
The replacement technology includes several steps that must be followed.
Determining the number of Li-ion batteries
In general, the parameters of the battery are marked on the battery itself or on the electric screwdriver. To determine the number of cells you need to divide the voltage indicated on the tool by 1.2V (this is the nominal voltage of one nickel bank).
To figure out how many lithium parts you need to replace, divide by 3.7V. this is the normal value for this type of battery.
It is recommended to round up the result, it will not negatively affect the tool, but just increase its power a little.
It is necessary to correctly select all the necessary elements for replacement
Choosing a Li-ion battery
Lithium-ion and lithium-polymer cells are available from manufacturers. The latter are smaller and safer, but also cost more. At the same time, they are not capable of delivering high currents. That’s why experts recommend taking regular lithium-ion cans.
It is better if the cell has welded flexible taps, because such parts do not like high temperatures and unnecessary soldering. It is recommended to look at several options in stores to choose the most suitable model.
How the battery voltage affects the life of an electric screwdriver
The question of how the value of the battery voltage affects the duration of operation of the product is of interest to many people. To understand how much power a product has, you must multiply the voltage by the battery capacity.
For your reference! For example, an electric screwdriver with a 14.4V battery and a 1.5Ah capacity would have a capacity of 21.6W.
Ready to use 18650 battery packs
As a replacement, it is better to buy pre-packaged assemblies of 18650 batteries. You can do this at Chinese online marketplaces or other online stores.
Choosing a BMS protection circuit board
Lithium ion batteries require careful handling and compliance with certain requirements. The role of protection is performed by the BMS board. This is the element that does not allow the voltage over 4.2V and under 2.55V per battery while charging. In addition, the cell controls the maximum allowable current and maintains the necessary balance between the batteries.
The main parameters are the number of cells connected in series. On the Internet you can see a table with all the necessary parameters and use it to choose the right board.
The replacement can be done even at home, the main thing is to follow the sequence
Power supply for charging
For lithium-ion batteries, chargers are chosen based on the number of cells in series in the battery. The more there are, the higher the output voltage must be.
Charging the batteries with standard battery charger of an electric screwdriver
If you want, you can buy a special universal board for the lithium battery. It is installed in the native charger. However, experts recommend to use the right charger for this type of batteries, not refinements.
Lithium battery capacity indicator
Indicators are available in LED and digital. The latter is cheaper, but not convenient to use. It is better to choose LED versions, based on the number of batteries in series.
18650 battery holder
It is also better to buy ready made holders for 18650 batteries. If you want you can find good options at affordable in online stores.
Metabo BS 12 NiCd electric screwdriver. Replacement of the batteries with Li-ion
Hello all.After four and a half years of use, the NiCd batteries in the cordless screwdriver were dead. Since it is used occasionally and is still in good condition, it was decided to restore.
The first variant. Buy new batteries. Was rejected for financial reasons (one battery 2250r).
I’ve been surfing the internet and decided to convert to Li-ion. Ordered these batteries (as an electric screwdriver 12 V, need three pieces per battery):
And these are the control boards, one piece. on the battery:
The money all together came out about 1500r. The replacement process will not describe, it’s simple: disassembled, tore off the old-soldered a new. Power wires 1.My battery has 5mm2 cross section and the control wire is kinda thin. left the line for the thermistor trimmer. I also left one of the old jars propping up the current collector connector. Solder the wire pots should be acid, I had not, according to the old school memory tinkled aspirin tablet. The good thing was to fix everything in the case with thermal adhesive, but I don’t have a gun, so I stuffed dishwashing sponge:
Pros: reduced weight. Previously one can assembly weighed 450g, but now the battery assembly weighs 345g. Current from 1.7A increased to 2.5А. I use regular charger with the function of controlling the charge, overheating and the condition of the battery:
Actually, I have a question for people knowledgeable in radio engineering. After a while the charger starts to blink red, allegedly a faulty battery. The way I figure it, BMS (charge control board) detected that the banks are charged, and shut off the current supply. The charger also registered this moment, “thought” that if the battery doesn’t take the current, it means it’s defective and gave a signal. I measured the voltage at the assembly after the fault signal was given, 12.5V, t.е. what’s needed. Turns out, the charger cutoff was implemented through the battery fault cutoff, and everything is great? And the battery is charging and you don’t need to make a charger, but use the regular charger? I would be grateful for any Комментарии и мнения владельцев from the experts. By the way, the screwdriver drives very well with these batteries! Do not stop with your hand. If you have any questions about modifications, I would be glad to help.
Not really. At the last stage of charging, lithium batteries, the controller reduces the charging current to very small values. If a nickel-metal hydride battery was charging at this current, it would mean it was already dying. Check. whether the regular charger turns off when the error is indicated, and you have lithium batteries in the eternal undercharged state.
There’s a more proper topic like this. https://mysku.ru/blog/ebay/17368.htmlAs far as I know, the charging of lithium and nickel-cadmium batteries is very different.
without a board, or improperly connected, or burned out, will be like this
1500 for three cans and a controller. Expensive. I think it costs 500 on ali.I’ve made one myself a few times.
It’s just not clear whether the regular charger charges well. Is the voltage correct?? Is it too much?? Isn’t that a little?
Why wouldn’t it be fine? Voltage and current are quite suitable. Here’s an excerpt from the instructions to the charger:
Expensive?One normal brand 18650 costs 500r a piece.
So instead of farting, it’s better to buy a normal screwdriver
You’ve done it yourself several times, but you don’t know how much it costs? It seems to you that 500 on Ali? So that’s it. You’re a common fuckwit. And try to start with these batteries from ali bring, the customs oh how they do not like.
Module with charge controller is usually put. It is available in our stores, I think it costs 250e, up to 6A. 18650 can be scrounged from notebook assemblies, Sony is better.
By the way, you are right not to remove the thermistor, I when he converted the screwdriver to lithium, first removed it and the whole thing does not want to charge, like a battery does not see.
volk55555The role of “their” charging board is BMS, and the charger simply supplies voltage.
You only need a control board for lithium ion? It’s not like it’s in the nickel caddy. So the control must be in the charge. But I don’t have one. It just signals. So it’s a good thing, too?
The regular charger charges the whole assembly at once, which is not good. One shriveled bank will give the charger the wrong information and stop charging. The control board controls the assembly one at a time. And the regular charger signals the end of the process of charging, and possibly transfer to the mode “drip charge” just to avoid “fucked up” banks. I have not dug that deeply, and regular chargers in different models are very different in terms of functionality.
Here the trick is that the lithium can not withstand overcharging and is very sensitive to deep discharge. T, e.,If it is heavily discharged, it may not be able to recharge. To avoid all these problems and serves as a controller. Someone wrote here that 1500 for everything is expensive.Normal lithium batteries cost from 700 for about one. But they come with a limit on both charging and discharging. The controller is not needed. And the lithium ones have a really special grip, but I’m too lazy to describe it in detail.
not so much. Those accumulators you are writing about are already equipped with exactly the same BMS board, but for one can, round in diameter as the battery. And it is structurally mounted directly on the battery on the minus side. These things https://ru.aliexpress.com/store/product/3-7. 76f4d4bbO1Kuyq