How to repair an electric screwdriver battery and its malfunctions
Cordless electric screwdriver, can always be useful in the economy, but over time, its power source suddenly refuses to work. It is expensive to buy a new electric screwdriver. Its price is about 70% of the cost of the battery. And since models change frequently, it is quite difficult to find a new battery just for this tool. So the question arises. what to do next? Buy an electric screwdriver or look for a similar battery? But this problem can be solved by repairing the battery yourself, prolonging its life for several more years.
It is worth noting that batteries for almost all brands of screwdrivers, regardless of what country they are manufactured, have a similar device. But each type of battery has its own specific characteristics.
If you disassemble the battery, you can see that its device consists of individual cells connected in a common circuit in series. Many should remember from their school years that the charging elements connected in series in one electrical circuit, the total power increases.
Types of batteries
Has a fairly high capacity, so that one full charge may be enough for 1500 cycles. But it needs constant charging. Also this type of battery is not recommended for use in low temperatures.
Practically the cheapest batteries with a rated voltage of 12.5 V. Their capacity is low, so they discharge relatively quickly. But they cannot be recharged. So to extend the life of these batteries, it is recommended that they be fully discharged before being charged. The advantage of nickel-cadmium batteries. quickly charged, with proper care fairly long operation and work well at low temperatures.
They have a large capacity, they charge quickly. Can be freely recharged at any time, but must not be fully discharged. Also not recommended for use at low temperatures. Do not tolerate long storage without periodic discharging and recharging (after a certain period of storage, it is recommended to give the battery a load).
There are two pins on the battery case, marked plus/minus for power to the electric screwdriver and 2 pins for charging. A thermistor is connected to one of the charging contacts, whose duty it is to protect the battery from overheating during charging. The thermistor completely shuts down or reduces the charging current when the batteries are heated to a temperature of 50-60 degrees. Batteries often heat up if they are subjected to intensive, so-called “fast” charging.
Causes of malfunction
Battery failure is possible for a variety of reasons. So before you try to restore it, you should make sure that this action is advisable. It may be that the labor and expense incurred to repair it will cost more than a new purchase.
For example, a frequent source of problems that causes the battery to stop working is its long life. For some types of batteries, after a certain period of time, the capacity of the batteries decreases, and they quickly discharge during operation. Naturally, in this case, most likely, it will not be possible to restore their performance.
There are also some other malfunctions:
Electric screwdriver battery malfunction detection and repair
Before you start to repair the battery, you should determine the fault of the battery, otherwise it will be quite difficult or impossible to repair it at all. It should be noted that the failure of all battery cells at the same time is impossible, except in rare cases where there may have been a prolonged short circuit of the battery output terminals.
To determine the fault, you should:
- Charge the battery and wait until it is fully charged.
- After that, disassemble the case, and measure the voltage of each charging cell. The voltage difference across the banks for nickel-cadmium batteries, can be in the range of 1.2-1.4 V, and the difference for lithium batteries can be about 3.8 V.
- Banks that have less than the rated voltage should be marked. After that, the battery should be reassembled and give it a full load until a noticeable discharge.
- Then disassemble the battery and measure the voltage of each bank again.
- Usually the biggest voltage sag will be in the marked elements, which will need to be “resuscitated” or simply replaced.
If the electric screwdriver requires 12 V voltage to work, you can try to find faulty elements in a simpler way. To do this, you need:
- Perform a full charge of the battery, then disassemble it and measure the voltage of each cell.
- Then use a 12 volt bulb to discharge it completely and measure the voltage of all cells again to determine which ones are faulty.
Instead of a light bulb, you can use a suitable voltage resistor.
Electric Screwdriver Battery Repair and Replacement
The most effective method of how to restore the battery of an electric screwdriver is to simply replace the failed charging elements that were found during their inspection.
To make a repair, you will need a donor, that is, a second battery, which also has failed banks, if there is no such, you can buy new cells through the Internet. Today there are enough online stores that are ready to deliver new batteries directly to your home by courier service.
Important. Acquired cells must match the capacity and dimensions of the cells to be replaced.
You will need to prepare the following items for the repair: soldering iron, tin solder, and alcohol flux (preferably).
The process itself of replacing the charging elements does not provide any complexity, if only there was a skill in soldering.
Electric screwdriver battery recovery
Warning. To avoid damaging the battery when working with a soldering iron, soldering must be done quickly.
For connection of elements it is recommended to use native plates, and if it is impossible to use them, to replace them completely on the same size, but from copper. This is necessary for the correct charging process. If the cross section of the connecting plates is different between the cells, they will be heated and of course to protect the charging batteries will constantly actuate a thermistor.
Care must be taken when assembling the batteries. The connection must be in series. the minus of each battery is connected to the plus of the next cell.
After all the cells have been completely reassembled, equalize their potentials, as they will be different for the time. This requires a certain charging/discharging cycle. The repaired battery will be fully charged and then allowed to stand for approximately 24 hours. After one day the voltages of all the cells should be measured separately, and if the assembly has been correctly done, the voltage of each cell should be equal to 1.2 V.
After that the battery should be fully discharged again. To do this, the assembled battery, with an electric screwdriver, is given a full maximum load until it is completely discharged. The main thing is not to overload the electric screwdriver itself, so it does not have to be repaired in the future. This charging/discharging procedure has to be repeated several times in a row.
In the same way, about every three months, it is recommended to conduct a procedure to erase the “memory effect”, which will prolong the battery and the electric screwdriver itself.
Electric screwdriver battery replacement
Without thinking too much, I bought 18650 lithium-ion batteries. Since my electric screwdriver is 18 volts, and one battery produces 3.7 volts, therefore, I needed 5 pieces. 5×3.7=18.5V is what I needed.I also bought battery compartments, one for two batteries and one for three. Wired everything in series. Took the old batteries out and replaced them with new ones.
Wiring diagram of the charging controller
The batteries are also connected in series, except that for each connection between the batteries to the controller there is a contact. As a result, the controller monitors the status of each battery and prevents it from overcharging in the circuit.I put together a circuit. Everything works fine.
How to repair the battery of an electric screwdriver
I think you all know the problem by now when one day you pick up your electric screwdriver and turn it on and it doesn’t work. Next, the first thing you try to do is put it on charge, assuming the batteries are just dead. But that’s not the case: Charging doesn’t work. This problem is as old as the world. The whole point is that inexpensive screwdrivers use relatively cheap nickel-cadmium (NiCd) batteries. They are quite tricky and if you don’t use them long enough they break down right away.I offer you to recharge your electric screwdriver so it is as good as new. For that we just replace the batteries with the same or better quality.Although on the Internet, most people recommend changing the batteries to lithium-ion (Li-ion), but I’m not in favor of a complete remodeling. After all, you can’t just replace them, because lithium-ion batteries have to be charged differently, put in a charging controller, use a different power source, etc.п. And the body of the battery itself will undergo significant changes. No, I just recommend to replace the batteries with the same ones, it is much cheaper and you don’t have to make up anything.
Restore the electric screwdriver battery pack
Well, now let’s proceed directly to the restoration of an electric screwdriver. Removing the top cover of the battery pack.
In order not to forget how the batteries are placed inside, I made a peculiar map on paper with their positions and poles. Do the same thing so you don’t have to wonder what goes where later.
Now you can disassemble this bundle to release the power terminals, which are just what you’ll need later.
They don’t solder closed batteries. Jumpers should be welded by means of contact welding. But since it is not available, we take a powerful soldering iron and it quickly solder.
Flux the pole, place the jumper, and quickly solder with a red-hot soldering iron, keeping the sting for no more than 1-2 seconds.
Then glue the common insulating sheets back on both sides and assemble the unit in the reverse order. Measure the voltage at the output terminals. It should be around 14.4 В. If so, then the sequence of batteries is correct. Let’s charge it up.
The main thing is that you can easily recharge your electric screwdriver without any manipulation and it will serve you for a very long time if you follow it properly.
The project involves taking the batteries off quickly (so that at the end of the work, you can easily put them on a stationary charger, such as the NITECORE I4 (At https://sdelaysam-svoimirukami.There are also articles on how to build a budget charger for these batteries)), so were used holders 2 x 18650.
To achieve the desired voltage. you need to connect the batteries in series (In this connection, the plus of the battery is connected to the minus of the next). Since I have used 2 holders they need to be connected to each other for current exchange
The original wires of the holders were too thin, so they could have a heat loss, to avoid this they were soldered to a larger diameter wire, taking into account the new location of the batteries.
For a rough indication of the battery charge level a 12 V LED connected in series with a 1 kOhm current limiting resistor was used.
The power supply of the LED should be brought out in parallel with the power supply of the electric screwdriver. For this purpose to the thick wires of the plus and minus of the battery pack soldered wires with a smaller cross section.
Wires with a larger cross section should be soldered to the terminals of the battery pack of an electric screwdriver, in my case they are placed on a separate plate, and then, the plate is returned to its normal position, if desired, fixing the glue.
To observe the LED in the body of the battery compartment must be made a hole (this is good for a heated nail).
Since the LED is an indicator, not a light, you can fix it in the hole, applying thermo glue (this will make the glow softer). Photo of an electric screwdriver after recycling.
Note that for the batteries to work properly in series, they must be “married”, in other words, they must be from the same batch, the same capacity and model. If you follow this rule, they will be discharged at the same time. To check the batteries and prevent them from overdischarging. use a LED (the lower the charge. the dimmer the light it emits. It is not easy to do without proper training, so be sure to check the voltage of the batteries with a voltmeter).
Screwdriver Battery Repair
Repair work includes the restoration of power sources or replacement of the batteries in the battery of an electric screwdriver with their own hands.
Before disassembly and repair, the battery is fully charged with the regular charger. Repair is done in the following sequence:
Disassembling the housing
The battery case consists of two parts. Screw joints are common. in these cases disassembly is easy. If you are gluing, you should thoroughly tap the glued parts with a mallet. As the adhesive layer breaks down, force should be applied to disconnect the parts. A sharp, thin knife inserted into the gap between the parts may help.
defective cells are detected
Order of operations to determine the defective batteries:
- elements are carefully inspected;
- Bloated, with traces of electrolyte leakage on the body, etc., are detected. п., which cannot be repaired, for replacement;
- A tester checks the output voltage on each jar. For nickel cadmium and nickel metal hydride cells 1.2 V and for lithium ion cells 3, 6 to 4 V depending on the model. This will be less if the battery is used for extended periods of time, but should not cause a decrease of more than 10-20%. The purpose of the test is to detect batteries with less than half of their nominal capacity.
Electrical capacity decreases as a result of irregular charging of the cells by regular charging. the instrument switches off when the temperature of the drum, on which the temperature probe is mounted, reaches the value of a full charge. Some of them may be undercharged in this case. This is detrimental for the Ni-Cd batteries, because due to the memory effect their performance deteriorates considerably after several cycles with incomplete charge.
- Connect the discharged cell in the correct polarity to a universal battery charger, such as the Imax B6. The device performs charging-discharging of the main types of accumulators by currents of different strengths in automatic mode with constant control of batteries condition;
- 2 to 3 cycles of full charge / full discharge with the appropriate current. This is usually sufficient to produce a high charge of the battery. This is repeated with other discharged cells. It must be remembered that in order to eliminate the memory effect a Ni-Cd battery needs 5-6 cycles of deep discharge/maximum charge.
There are other ways to make batteries work again
- short term exposure to currents much higher than the charging current. It is claimed that any “dead” battery can be quickly restored in this way. Indeed, when exposed to pulsed current of 10 or more times the charging current Ni-Cd and Ni-MH batteries quickly reach the nominal capacity. However, this effect lasts for 2-3 cycles, then the battery is usually not recoverable.
- adding distilled water inside the cell body: a small hole is drilled in the body and 1 cc is inserted through it. see. distillate, the cell is fully charged. After a few days the charge level is checked: if it is low, another 1 cu. see. of water and the battery is recharged.
When the normal capacity and voltage values are reached, the case is sealed and the battery is ready for use. This method is more efficient than the method of charging with high pulse currents.
Reassembling the Battery
Once the electric screwdriver battery repair is complete, the battery can be reassembled:
- the cells are inserted into the base of the battery case without much effort. soldered connections are not as reliable as welded ones and can be damaged;
- wires to battery terminals are inserted without major kinks. They are not allowed to come into contact with each other or with the poles of the jars;
- When assembling lithium batteries, the controller board is insulated from the cells with a gasket of cardboard, polyethylene, etc. п., to avoid a short circuit in the circuit;
- Parts of the housing are fastened together with screws, if so specified in the design, or by means of glue. We recommend adhesive sealant. the connection is reliable and airtight, and if necessary, quick disconnectable.
Replacement of defective elements
Reduced performance of long lasting power supplies indicates irreversible chemical changes in the components. Methods of restoring the capacity extend the battery life by 10-15 cycles. Then new cans must be installed. The replacement of the batteries in an electric screwdriver is performed in several steps.
- The elements to be replaced are identified. New units must match the dimensions and specifications of the ones being replaced. This is especially important for lithium-ion or lithium-polymer cells, because the controller is programmed to work with batteries with strictly defined specifications. Otherwise the product may not be operated safely.
- If all elements are replaced, the bundle is disassembled. The metal plates connecting the poles of the jars are removed. They are needed for connecting the new elements. If you have a large number of elements, it is better to draw their configuration, indicating polarity, the place of attachment of the temperature sensor, etc. д.
- The sources are connected to each other in series by metal plates. In industrial fabrication, spot welding is used for this. This will not heat up the case or damage the battery.
At home, a soldering method that excludes prolonged heating of the battery is used:
- Metal plates are tinned using active flux F-38H at a soldering iron temperature of 250-300 ºC;
- the junction on the jar is treated with flux;
- molten solder is applied to the contact area of the plate, the soldering iron is held on the plastic;
- the heated plate with solder is pressed to the point of contact on the can, the soldering iron at the moment of contact remains on the plate;
- the soldering iron is quickly cleaned up.
The soldering experience heats the battery for less than a second, which does not harm it. The method is suitable for connecting Ni-Cd and Ni-MH sources that are less sensitive to heat. It is better to use spot welding to connect lithium batteries.
All of these tips will help you repair your electric screwdriver battery in a variety of ways so you don’t have to spend money on a new one. Do not forget about safety precautions, take your time and you are sure to succeed.
Electric screwdriver battery repair with your own hands
Why the battery does not hold a charge well? How to work if the electric screwdriver does not work more than 10 minutes after charging? Such questions arise from users whose cordless tool has been in use for more than a year. There are several solutions to this problem. You can, for example, contact a service center. They will most likely offer you to buy a new battery, because officially specialists do not repair dead cells. But what if such models are no longer produced, and you can not find a suitable analogue?? Is it really so that you have to part with your favorite tool and buy a new one, with a new battery and charger?? With the current not everyone can afford it. That’s why many craftsmen take up the repair of the battery of an electric screwdriver with their own hands. By the way, not all of them are chasing economy. For some, it’s a creative outlet, an opportunity to breathe new life into an old tool. After all, you can not make it worse, but it is worth trying!
In preparing this article, we have studied many examples of electric screwdriver battery repair with our own hands. Some users only restore the cells, others create a completely new battery on the basis of cheap Chinese batteries. However, such approaches are not always good. For example, the cells of lithium-ion batteries can not be restored. When restoring nickel-cadmiums, sometimes you need to flash the cells, and therefore a special device. The universal way is to repair the battery with the replacement of individual cells. This is what our article will tell you about.
What you need
Dismantle the battery case
The case of any battery is collapsible. Consists of two parts that are connected by small screws or glue. In the first case, everything is simple: you just need to unscrew the screws and separate the parts. If the body is glued, you will have to work hard to accurately get to the cells without damaging them. First you need to put the edge of the knife at any point on the joining of the parts and then put something sharp, for example a self-drilling screw, through it. In this way, it is possible to unclip a single section. Then it is necessary to carefully go along the whole perimeter with a blade, separating the glued parts. The case is disassembled. After the repair it will need to be glued again.
Determine the fault
When you get to the battery cells, you will see that they are banks connected in series. So, one defective cell can be the cause of poor operation of an electric screwdriver. An important step in repairing the battery of an electric screwdriver with your own hands is to find this weak link.
The test must be done with a fully charged battery. All the cells should be removed from the enclosure and, for convenience, laid out on a table so that the connecting pins are easily accessible. Use the pins of the multimeter to measure the voltage at each bank, be sure to record the reading. For convenience, you can draw a diagram on a piece of paper and write down the readings there. You can mark them directly on the cells.
Useful information: for nickel-cadmium batteries, the voltage of each cell must be within 1.2 to 1.4 V, and for lithium-ion batteries it must be within 3.6 to 3.8 V.
After measuring the voltage of the battery is assembled and work with an electric screwdriver until the loss of power. Then they disassemble it again and measure it again, and then write it down. On cells that at first measurement had the lowest voltage values, the greatest losses are observed. It is worth noting that a significant difference in the voltage of the banks is considered 0.5. 0.7 V. These are the cells that should be replaced.
As a side note! When repairing an electric screwdriver battery with your own hands, replacing the cells is considered more effective than repairing them. The fact is that the restored banks will not last long, and soon they will have to be replaced anyway. So it’s better not to do double work, but to replace them at once.
Replacing damaged cells
With the upcoming self-repair of the electric screwdriver battery, many users are faced with the question of where to get new batteries. You can find an old battery, for example, from acquaintances or visitors of thematic forums. Use it as a donor and take away from it working cells. You can buy the cells separately. They are sold in radio and electrical stores or on private ads. Some craftsmen order batteries from Chinese sites. Agree that it is not that much money compared to buying a new battery.
Tip: When choosing, pay attention to the fact that the new cells should be similar in size and current values to the cells you are replacing.
The process of replacing damaged cells is quite simple. It will not be difficult for those who have had to deal with soldering. First you should carefully cut the connecting plate and remove the defective can. Try to keep this plate to attach the new cell. Installing the new bank, make sure the plus and minus sides are positioned correctly. When connecting in series, place the cell so that the minus of the previous one goes to the plus of the new one. To keep the jars securely in place, you can fasten them around the perimeter with duct tape.
Warning! Try not to overheat parts and work fast during soldering. This rule is important to observe to avoid overheating the battery. Otherwise there is a risk of damaging it.
Charge and discharge the repaired battery
After repairing the electric screwdriver battery, the potentials on the cells will be different, so they must be equalized. Leave the assembled battery to charge for a long period of time, e.g. overnight. Then leave it to cool down for about 24 hours. After that, check the voltage of all the elements. If all processes are performed correctly, the readings on each bank will be the same, for example 1.2. 1.3 V.
The next step is to completely discharge the battery. Operate the electric screwdriver until the charge is gone. After that, fully charge the cell. Repeat the charge/discharge cycle 2 more times. This will help prolong the life of the battery.
Let’s say that you should not take this article as an exact guide in repairing the battery of an electric screwdriver with your own hands. This is just one way to bring a battery back to life. If the subject interests you, study it on tool forums, talk to craftsmen who share their experience, ask them questions. Try to repeat their experience. for sure you will succeed just as well.
How to replace the battery for an electric screwdriver
Hello dear friends! Cordless electric screwdriver is an indispensable tool in the arsenal of home master. But, sometimes the battery of your favorite electric screwdriver fails and you wonder what to replace it with. The cost of a cordless electric screwdriver is 70% of the cost of the battery. Therefore, a difficult question arises:.What to do? Buy a new battery or a new electric screwdriver, or maybe you can repair the old battery with your own hands, or replace it with a cheaper equivalent. With my favorite electric screwdriver after six months of use had the same problem, the battery was in bad shape and I did not think twice and decided to install a more powerful battery from an old UPS.
Soldered the wires to the inner power strip of the electric screwdriver, the battery is tightly sealed with electrical tape in place of the regular one. It turned out pretty good, if you ignore the power supply voltage mismatch and the significant increase in weight. The supply voltage of the electric screwdriver “Interskol” 14,5 volt, and the battery from the battery-uninterruptible power supply gives out 12 volt. As practice and the tests made by me showed, the mismatch of supply voltage, particularly on the speed of screwing screws does not affect.
The electric screwdriver handles high loads of wood screws up to 100 mm, and thanks to the increased battery capacity of up to 7 Ah the working time is considerably longer. The battery charge at an average load is enough to screw about 300 self-tapping screws in wood with a length of 50 millimeters. The weight of the battery is a little strained and amounts to 2.3 kg.
Weight of an electric screwdriver with a battery of 3.2 kg. After three hours of training my muscles came back to normal, and I stopped paying attention to weight. It’s good for your health and keeps your work moving. Want to lose weight? Then lengthen the wires, put the battery in a small purse and hang it over your shoulder. There is another option is to install a smaller battery at 4.5 amps 12 volts, which can easily be pulled out of a small UPS or buy in a store like “Electrical Supplies”.
To charge the battery, I use a home-built battery charger from a computer power supply unit. Initial charging current is 10% of the battery capacity i.e. 0.7 A, charging time is about three hours.
Metabo BS 12 NiCd electric screwdriver. Replacing batteries with Li-ion
Hello all.After four and a half years of use the NiCd batteries in the electric tool died. 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).
After surfing the Internet I decided to convert to Li-ion. Ordered these batteries (because the electric screwdriver 12V, you need three pieces per battery):
And these are the control boards, one piece at a time. on the battery:
The money total came out about 1500r. I won’t describe the replacement process, it’s simple: disassemble-tear off the old-solder the new. Power wires 1.5 mm2 in cross-section, the controlling ones are thin. left a line for the thermistor trimmer. I also left one of the old cans, it’s propping up the current jack. Solder cans should be acid, I did not have, in the old school memory tinkered with an aspirin tablet. I should have attached everything to the case with hot melt glue, but I don’t have a gun, so I used dishwashing sponge:
Pros: reduced weight. One can assembly used to weigh 450g, but now the battery assembly weighs 345g. Current from 1.7A increased to 2.5А. I charge with the regular charger with the function of monitoring the charge, overheating and battery status:
Actually, there is a question for people who know about radio engineering. After a while of charging process, charger starts blinking red, supposedly faulty battery. The way I figure it: BMS (charge control board) detected that the jars are charged, and shut off the current supply. The charger also detected this moment, “thought” that since the battery was not drawing current, it must be defective, and gave a signal. I measured the voltage on the assembly after the fault signal, 12.5V, t.е. Just what I need. So, the charger cutoff was implemented via a battery fault cutoff, and everything is great? And the battery is charged, and you don’t have to make a charger, and use the regular one? I would be grateful for Комментарии и мнения владельцев from experts. By the way, the screwdriver with these batteries is very cool! You can’t stop it with your hand. If you have any questions about the redesign, I’d be happy to help.
Not quite so. At the last stage of charging, lithium acumens, the controller reduces the charging current to very small values. If you were charging a Ni-MH battery with this current, it would mean it’s already dead. Check. Does the regular charger turns off when it indicates an error, and you get the lithium batteries in the eternal undercharged state.
Here is a more proper similar topic. https://mysku.ru/blog/ebay/17368.htmlAs far as I know, charging lithium and nickel cadmium batteries is very different.
Without the board, or improperly connected, or burned out, it would be like this
1500 for three cans and the controller. expensive. I think that such a thing on ali worth 500.I’ve done this myself a few times.
I just don’t know if the regular charger charges well. Is the voltage appropriate?? Isn’t that much? Isn’t it too low??
Why wouldn’t it be okay? The voltage and current is just right. Here is an excerpt from the manual to the charger:
Expensive?One normal brand 18650 costs 500R each.
So instead of farts, it’s better to buy a normal screwdriver
I myself have done it a few times, but you do not know how much it costs? Seems like you got the 500 from Ali? So, that’s it. You’re a regular fucker. And try to start with these batteries from ali, the customs don’t like them very much.
The module with the charging controller is usually. It is available in our stores, I think it costs 250e, up to 6A. 18650 can be scrounged from laptop assemblies, better from Sony.
By the way, it is correct that you have not removed the thermistor, I when he converted the screwdriver to lithium, first removed it and the whole thing does not want to charge, type does not see the battery.
volk55555The “own” charger is the BMS board, and the charger simply supplies the voltage.
Control board is only needed for lithium ion? It’s not in the nickel caddy. So the control board should be in the charger. But I don’t have it, I just get a signal. So it turns out that the batteries can get fucked up too?
OEM charger charges the entire assembly at once, which is not good. One shriveled bank would give the charger the wrong information and stop charging. Control board controls the assembly step by step. And the regular charger signals the end of the charging process, and probably switches to “drip” charging mode, just to avoid “fucking up” the banks. I did not dig that deep, and regular chargers in different models are very different in terms of functionality.
The thing is, lithium can’t withstand overcharging and they’re very sensitive to deep discharge. Ie.,If it is deeply discharged, it may not be able to recharge. To avoid all these problems and is a controller. There is someone wrote that the 1500 for everything is expensive.Normal lithium batteries cost from about 700 for 1. But they already come with a limit on both charge and discharge. No controller needed. A lithium battery really special, but too lazy to describe.
not so much. Those accumulators you write about are already equipped with the exact same BMS board, but on a single can, round shaped like a battery in diameter. And structurally it is installed directly on the battery from the minus side. Here are these things https://ru.aliexpress.com/store/product/3-7. 76f4d4bbO1Kuyq