How to Disassemble a Makita Electric Screwdriver Battery Intelligently and Quickly

I’d like to share with you two interesting pieces of news that have changed my way of life over the years:

December 16, 2015 I had a son. Yaroslav:))) Now I have a Laddy daughter and two sons. 2. Shortly before the birth of my son the worst thing happened. The battery of my Makita electric screwdriver, which had been working faithfully for almost five years, “died”:(

#Teardown #Inside of #Bosch Go (Gen 2.0) #128736;#128165; #Cordless #Screwdriver

Of course the first event is much more important to me, but I will introduce it to you in the next article of my blog:)

But the news that the battery of an electric screwdriver finished undermined my already shaken health, as the “deceased” was immediately buried and I drank a certain amount of alcohol for the repose of his 14-volt soul Let the Megavolt be with him.

Of course, during all the years of his construction and repair career yours truly “shaken up” a huge number of electric screwdrivers, but the Makita was a real godsend for me. Its ergonomics, its reliability. I was won over at first sight!

In general, I could not accept the loss and decided by all means to repair the battery of an electric screwdriver.

Having read a lot of literature, having graduated with honors from the courses of “Beginning Blacksmith”. The department of applied necromancy, i.E. Reviving the dead. I began to work, but from the first steps I realized that in order to restore the battery of an electric screwdriver it must be disassembled.

How to rebuild a Makita 12 volt electric screwdriver battery by applying high currents

Apply a pulsed current to the problem battery using the popular Imax B6 battery charger, or similar. Before starting the job, it is necessary to:

If the amount of electrolyte remaining in the jars is not great, you cannot begin recovery, because.К. It will ruin the battery. Replace the missing volume of electrolyte with distilled water, and only then begin reconstruction.

To fill the water, a thin drill hole is made on the side of the battery as close to the top edge as possible. Water is poured with the help of a syringe with a needle until it fills one hundred percent of the can. This procedure is repeated for all batteries, leaving the filled batteries to stand for a day.

After that, the battery bundle (“cassette”) is connected to the Imax B6 for charging with the parameters: 12 volt by short pulses, the resistance value is 40 ohms. When the batteries are 100% charged, leave them for another day. Check the voltage of each battery cell with a multimeter to see if the voltage has decreased. If an undercharged battery is found, refill it with water, charge it again and check the voltage again.

When each bank holds a stable charge, the drilled holes are sealed with silicone adhesive.

Detecting a malfunction

With the purpose of the elements of the battery design understood, now let’s consider how to determine the fault, it is h.2 electric screwdriver battery repair. It is necessary to notice at once that all elements cannot fail at once, and as the circuit at us consecutive, at an output of one element. All circuit does not work. So, our task is to determine where in our circuit the weakest link is.

For this we will need a multimeter, and for the second way to find the fault a 12 volt lamp, if your battery on the electric screwdriver is also 12 volts. The procedure is as follows:

Note. The difference between the cells in the battery of 0.5. 0.7V is considered to be significant, this means that the cell is becoming unusable.

Thus, we have found candidates for “resuscitation” or “amputation” and replacement with new elements.

Makita LXPH01 Drill repair of an burned MOSFET

If your electric screwdriver is 12 or 13 volts, you can search with a simpler method. Fully charged battery disassemble and connect the 12 volt lamp to the terminal “” and “-“. The lamp will be a load, and will discharge the battery. Next, we measure on the battery cells, where the greatest voltage drop is, there is the weakest link.

There are other ways, instead of the lamp you can pick up resistance, but for this you need the basics of electrical engineering, and it is doubtful that the resistor with the required resistance would be handy.

Other faults are very rare. For example, the loss of contact in the soldering points of batteries or power contacts of the unit, failure of thermistor. This problem is more inherent in counterfeit. Due to the rarity, we will not focus on the battery elements.

The “problem” elements are dealt with, it is necessary to repair. How to Repair an Electric Screwdriver Battery? In general, 2 ways are available for repair, if I may say so. This is the restoration and replacement of elements that have fallen into disrepair.

How to repair the battery of an electric screwdriver. Build your home

When working with a cordless electric screwdriver sooner or later the battery begins to run down quickly, or it stops charging at all. Work in such conditions is almost impossible, so you have to either buy a new battery, or restore it with your own hands. On how to restore the battery of an electric screwdriver, and we will talk in this article.

The design features of batteries for an electric screwdriver

The structure of batteries of different types of the power tools does not differ much from each other. The battery of an electric screwdriver is a daisy chain, consisting of identical cells. And in most cases these cells have the same size and voltage (V) output. The only difference is the cell capacity, which is expressed in mA/h and is indicated on the housing. When you repair the battery for an electric screwdriver, you must pay attention to the type of cells used (Ni-Cd, Li-Ion, Ni-MH), because the recovery technique for each of them may be different.

To be able to charge the cells and power the power tool in the design of the electric screwdriver battery, there are power contacts (“” and “-“), connected to the pins of the serial circuit. To protect the equipment from overheating during overcharging and to equalize the charge level at all banks of the battery, two more control contacts are used, through which the thermistor and the resistance are connected.

Locating a Battery Defect in an Electric Screwdriver

Since all cells are connected in series, the first thing to do is to find the weakest link, since if at least one cell fails, the battery will operate with significant technical deviations. There are several methods for determining if the battery pack is faulty.

Locating an electric screwdriver battery malfunction with a multimeter

Given that all cells in the circuit have the same voltage level, the faulty cell can be determined using a multimeter, switching it to constant voltage measurement mode. It should be taken into account that the nominal voltages for different types of batteries have different values:

The method of determining the failed battery cell is based on the following algorithm:

• The battery is placed on a full recharge.
• The case of the device is disassembled and the voltage of each bank is measured.
• The elements with a voltage below the established norm are marked. For Ni-Cd and Ni-MH batteries the voltage should range from 1.2 to 1.4 V, for Li-Ion. From 3.6 to 3.8 V.
• The battery is assembled and installed in an electric screwdriver, after which it should be discharged to a noticeable decrease in power, for which a number of power operations can be performed with the power tool.
• After discharging, the battery case is disassembled again, and the voltage in all areas of the circuit is measured. Particular attention should be paid to labeled cells.
• If the cell voltage drops to 0.5. 0.7 V, the battery is considered unsuitable.

Fault detection in the battery of an electric screwdriver by means of a load

The technology of identifying weak batteries with the help of the load is similar to the above described, the only difference is that to discharge the battery here is used a 12-volt bulb, for example, 40 W, which will act as a load. In this case it is not necessary to assemble/disassemble the battery pack several times. After performing all of the above manipulations, all unreliable elements of the battery circuit are determined, and then the decision to replace or restore them is made.

Restoring the battery cells from an electric screwdriver

To restore the battery from an electric screwdriver it is necessary to remember that it is almost impossible to restore the Li-Ion battery, and all that can be done in such a case is to identify the damaged elements and make their replacement. Sometimes the problem can also hide in the charger, which is why you should also pay special attention to the correctness of its operation.

If we talk about the reanimation of blocks, the method of restoration can be applied only to Ni-Cd batteries, which are the most common for screwdrivers.

Among the main techniques to restore Ni-Cd batteries are the following:

How to eliminate the memory effect of the battery

It happens that the battery needs to be restored, which is associated with the erasure of the memory effect. And to recognize such a defect is very simple. Once fully charged, the battery is discharged very quickly, and can function again after a short dwell time. Part of the correct way to remove the memory effect is as follows:

In the beginning the battery is fully charged with a small current and then the battery has to be fully discharged by applying a small load and thus ensuring a slow discharge that will drain not only the outer layer of the battery but also all the plates of the battery as a whole. As the load in this case it is advisable to use an ordinary lamp with a voltage of 220 V and a power of 60 watts. The battery should be discharged to 30% of its nominal capacity (about 5 V).

Before using the battery, the above procedure should be repeated at least 5 times. And although the capacity of the battery of an electric screwdriver will be somewhat lower than a new battery, yet, as a temporary measure, this technique is quite successful and can prolong the work of the battery for at least a year.

Screwdriver Battery Replacement

The easiest way to repair the battery with your own hands is to replace the failed cells with new elements. For which, before repairing the battery of an electric screwdriver, it is necessary to buy new elements, and the new elements should be identical to the others. Replacement of defective elements does not cause much difficulty. You will only need a soldering iron. In order to fully restore the operation of the battery during the work it is advisable to adhere to the following recommendations:

How to eliminate the memory effect

When a battery is very frequently undercharged and then discharged, it develops what is known as a memory effect. That is, the battery gradually as if memorized the minimum limit of charging and discharging, as a result of its capacity is not used fully and gradually decreases even more.

This problem is most common with nickel cadmium batteries and is less prevalent with nickel metal hydride batteries. In any case it is necessary to restore the capacity of the battery. The memory effect does not apply to lithium-ion batteries at all.

In order to solve the problem of whether the cell can be repaired, it is recommended to perform a complete discharge and charging of the battery with a 12 volt light bulb. The plus and minus wires are soldered to it and connected to the battery terminals. This procedure is repeated five times or more.

What you need to know before you start rebuilding a screwdriver battery?

The screwdriver battery repair service is professionally provided by Neovolt (click here for assistance).

Figuring out what’s wrong with your screwdriver battery

It’s best to replace the battery so you have plenty of capacity for the power tool’s long life. In the store you will find complete batteries for models from all kinds of manufacturers.

Fault detection and restoration of the electric screwdriver battery

Before you begin to repair the battery, you must determine the fault of the battery, otherwise the repair will be quite difficult or impossible. It should be noted that the failure of all cells simultaneously battery is not possible, except in rare cases where there may be a long circuit of the output terminals of the battery.

To determine the malfunction should:

• Put the battery on charge and wait until it is fully charged.
• Then take the case apart, 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 of lithium batteries can be about 3.8 V.
• The banks with a voltage less than the nominal should be marked. After that, the battery should be reassembled and given a full load until a noticeable discharge.
• Then disassemble the battery again and measure the voltage of each bank.
• Usually the biggest voltage drop will be in the marked cells that need to be “resuscitated” or just replaced.

If the electric screwdriver requires a voltage of 12 V to work, you can try to find the faulty elements in a simpler way. To do this you need to:

• Make a full charge of the battery, then disassemble it and measure the voltage of each cell.
• Then use a 12 volt light bulb to discharge it completely and measure the voltage of all cells again to determine which ones are defective.

Instead of a light bulb, you can use a suitable voltage resistor.

Repair and replacement of electric screwdriver battery cells

The most effective method of how to restore the battery of an electric screwdriver is a simple replacement of 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 elements through the Internet. Today, there are enough online stores that are ready to deliver new batteries directly to your home by courier service.

Important. The cells you have purchased should be exactly the same in capacity and dimensions as the ones you are replacing.

For the repair you will need to prepare: soldering iron, tin solder and alcohol flux (preferably).

The process of replacing the charging elements does not provide any difficulty, if only there was a skill in soldering.

Restoring the battery of an electric screwdriver

Warning. To avoid damaging the battery when working with the soldering iron, soldering must be done quickly.

To connect the cells it is recommended to use the native plates, and if it is impossible to use them, completely replace them with the same size, but of copper. This is necessary for the correct charging process. With different cross section of the connecting plates between the cells, they will be heated and of course to protect the charging jars 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 are fully assembled, equalize their potentials, as they will be different at this time. For this it is necessary to carry out a certain charge/discharge cycle. The repaired battery is fully charged, after which it should rest for about a day. After one day you should measure the voltage of all the cells separately, and if the assembly has been done correctly, the voltage of each cell should correspond to 1.2 V.

The battery must then be fully discharged again. To do this, the assembled battery, using 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 that it does not have to be repaired in the future. This charging/discharging procedure must be repeated several times in a row.

In the same way, every three months or so, it is advisable to carry out a procedure to erase the “memory effect” which will prolong the operation of the battery and the electric screwdriver itself.

Repairing the battery of an electric screwdriver by purchasing new Ni-Cd cells

In this case it is a question of replacing the battery cells completely and “erasing the memory effect” of the new batteries in order to make them more productive. The memory effect is that the battery “remembers” all the possible cycles of charging, which it can theoretically be subjected to in the workplace before it gets into someone’s hands. The more such cycles in its “memory”, the more likely it becomes that the capacity will start to decrease much earlier than expected. Also nickel cadmium batteries like such “rocking” processes. If they are carried out immediately before use, they work much better.

You can order the right amount of batteries online, for example on Ali-Express. It should be kept in mind that they already have a certain factory charge, which it is advisable to “remove” in order to “save” the strength of the batteries during operation. You can do it using the same battery charger Imax B6, the menu is not difficult to understand.

Let’s assume that the battery of an electric screwdriver should consist of 10 cells with the following indicators: the output voltage of each is 1.2 V and the capacity of 1200 mAh, which in total is 12 V. The advantage of a complete battery replacement followed by “erasing” the factory “memory effect” is that in any online store you can order cells with higher capacity than the old. For example 1800 mAh. And the battery will last much longer. Of course, such batteries will cost more. But the price is always worth it.

First use a multimeter to check the voltage of each “bank”. This will immediately help to determine the quality of new batteries and whether there is no vendor dishonesty who might have sold old cells instead of new ones. The voltage level of each battery should be approximately 1.3 V. When measuring, it is important not to confuse the terminals.

Then the “erasing of the memory” is done with each cell in turn. On the charger the following parameters are set: if the capacity is 1800 mAh, it can be set a little more. 1900, with a little reserve. Then change to the nickel cadmium batteries charge mode. The charge parameters should be the following: current value 0.9 A (half of the 1800 capacity).

Each new cell is subjected to a charge-discharge cycle in order to remove the factory parameters. At a current of 1A all the batteries are discharged one by one to a voltage of 1V (the minimum allowable voltage so as not to kill the battery).

Then go into charge-discharge cycle mode and start it with the “start” button. After discharging and removing the factory memory, place the batteries back in the unit, referring to how the old ones were previously placed there. Therefore, when disassembling the plastic case, you need to remember how the batteries used to lie.

So, there are many ways to restore the battery of an electric screwdriver with your own hands. Each of them has certain nuances, disadvantages and advantages, which should be considered depending on how you restore the vessel. Sometimes you should try hard to acquire a particular tool or the necessary ingredient (such as distilled water) in order for the recovery to be as successful as possible. But this is what will help you avoid the additional costs associated with the purchase of a new electric screwdriver or a completely finished battery.