How to repair the battery from an electric screwdriver

Problems with the battery

What can be the problem with batteries:

leaking; cannot be removed; decreased capacity; no charging; decreased charging and discharging time.

Nickel batteries can be refurbished. A lithium ones cannot be used because they decompose lithium. Here you can only replace the bad batteries.

Cordless electric screwdriver. which power sources are used?

Accumulators are equipped with the following types of elements:

lithium-ion (Li-Ion). with 3.6 V cell voltage;nickel-cadmium (Ni-Cd). 1.25 V for each cell;nickel-metal hydride (Ni-Mh). 1.2 V.

Evaluation of lithium-ion power sources in terms of quality and life puts them beyond competition. They practically do not self-discharge, high capacity, it is possible to charge them repeatedly, several times more than other types of batteries. Cell voltage is three times higher than for other types, which allows batteries to be packaged with fewer cans, reducing weight and size. They have no memory effect, which makes them an ideal device of this kind.

But there is no such thing as a perfect battery, and lithium-ion power sources also have some shortcomings. They cannot be used at sub-zero temperatures, as the manufacturers honestly state. But practical use has revealed another disadvantage: when the operating life of such a battery (three years) ends, the lithium decomposes, no ways to make a reverse reaction do not work. The price of such batteries is three times higher than that of other electric screwdriver power supplies.

Nickel-cadmium batteries are the most common because of their low cost. They are not afraid of negative temperatures, as lithium-ion voltage sources. If an electric screwdriver is rarely used, these cells are ideal because they can be stored uncharged for long periods of time while retaining their characteristics. These batteries have a lot of disadvantages: they have small capacity, they are toxic, so their production is concentrated in the underdeveloped countries. Self-discharge tendency, short life time under intensive use are also disadvantages of these batteries.

Nickel-cadmium batteries dry out at the end of their useful life. Those who know about this feature refill them, but this operation is not easy, so few people dare to do this action, preferring to replace individual battery banks. If the cause of failure is the memory effect, which is considered a big disadvantage of nickel-cadmium batteries, it is possible to restore their performance by flashing.

Nickel-metal hydride batteries are environmentally friendly, of high quality, produced by the world’s leading companies. In comparison with Ni-Cd have a definite advantage:

slow self-discharge; memory effect is small; resistant to multiple discharge/recharge cycles; of comparatively high capacity.

But if stored for a long time without work, they lose some of their characteristics, they do not like low temperatures, and they cost quite a lot. And the main drawback. they cannot be repaired.

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Causes of electric screwdriver battery failure

Most often the battery of an electric screwdriver stops working for such reasons:

• the electric screwdriver has been sitting idle for a long time. Downtime is as much the enemy of technology as overvoltage. the battery (rechargeable acid battery) must have a stable charge and discharge cycle to ensure that it will last a long time.
• the electric screwdriver or the battery itself has been stored at an unsuitable temperature. High temperatures should be avoided. Lithium-ion batteries, for example, are best kept in the refrigerator, but should not be used with the electric screwdriver immediately. The charging cell has to warm up at least a little.
• Sometimes the electric screwdriver’s automatic protection system discharges the batteries to their limits and requires a high input current to “revive” them.
• Overheating on a regular basis. This can lead to a gradual evaporation of water or electrolyte from the electric screwdriver battery (depending on the type of battery), which can lead to gas accumulation and deformations.

There are also typical private causes for each type of battery. Nickel-cadmium batteries or Ni-Cd batteries are known for the so-called memory effect. the loss of a large part of their energy capacity over time. In Li-Ion type batteries, lithium decomposition is common. This is a severe case, and repair is better than buying a new battery. In general, most breakdowns of batteries for screwdrivers can be repaired even without the services of a craftsman.

Important! If even one jar fails, the entire battery of the electric screwdriver is affected. Soon the rest of the elements will begin to deteriorate as well.

Electric screwdriver malfunctions

Despite the variety of power sources for batteries, they all have a similar structure, which means that their faults are the same:

• Breakage of the chain connecting the banks;
• Loss of capacity (one or more);
• Evaporation of the electrolyte;
• Lithium decomposition (only in some batteries).

Decreasing battery cell capacity is a common problem that happens even when the device is used briefly. The reason for the malfunction is that even when a single charge loses capacity, the remaining banks can no longer fully charge. The result is the reduction of the time during which the electric screwdriver can be used without interruption.

The reason for this kind of breakdown is the “memory effect” or the evaporation of the electrolyte in the batteries which occurs when they are very hot. Nevertheless, even with such troubles can be managed at home without resorting to professionals.

The dead cells are repaired or replaced with new ones. The second case is relevant for lithium-ion batteries, in which the lithium has decomposed. in this case you will only have to buy a new power source.

Can the cells be “reanimated” and how?

Let’s proceed to the h.3 electric screwdriver battery repair and we should immediately stipulate that the term “resuscitation” does not apply to lithium-ion batteries. There is no memory effect, most likely the lithium has decomposed, and there is nothing you can do about it. In such batteries, it is necessary to find out what is the cause of the malfunction: the cell itself or the control circuit. Here are two options:

• change the control circuit from the other but similar to our battery, if it helped. find a replacement and change it;
• Apply 4V to a cell with a current of about 200mA, which requires an adjustable charger. If the cell voltage rises to 3.6V. the cell is intact, the problem lies in other cells or in the control circuit.

Electric screwdriver battery reanimation repair is available mainly for Ni. Cd batteries, but they tend to be the most common in household screwdrivers.

So, how to resuscitate the battery of an electric screwdriver? There are two types of “resuscitation” for these types of batteries:

• The method of sealing or compression (it will work in cases where the electrolyte is still present, but the volume is lost);
• “Flashing” with a voltage and current greater than the nominal. This method allows you to eliminate the memory effect, and although not completely, but restore the lost capacity.

Note. As a rule, the main reason of capacity loss in the nickel-cadmium battery is boiling of electrolyte, and if it is critically low, no amount of “firmware” will not help.

This method, if its result is positive, will not solve the problem of a failed cell. Rather, it will only delay the replacement of defective batteries and later will still need to repair the battery of an electric Makita screwdriver or any other.

How the battery for an electric screwdriver is designed?

And it turned out to be simple as triviality. In the case there were 15 accurately packed in paper insulation and soldered together by means of spot welding. The number of batteries pleased me, because I know for a fact that if a finger cell battery has 1.5 volts, then the same exact battery has only 1.2 volts, which means the batteries are quite standard. Beside the barrels, I found a part with a strange appearance and unknown purpose. The part has a marking on it: D7AB 17AM026A5-540. You can find this marking on the Internet, but what is it. I couldn’t find. And there was one more thing. It didn’t look very pretty. Just like a piece of wire, but the fact that it was glued to one of the barrels with white paste made me suspect that this part is a thermistor. I took a multimeter, set it to measure resistance and connected the device. Then I started heating it up. The resistance began to decrease rapidly. So it really was a thermistor.

Why would an electric screwdriver battery need a thermistor?? It’s very simple. It seems that a professional and high quality device is shaped for super fast charging. Batteries can overheat at such a fast charge, and a smart charger prevents this by either limiting the charging current or turning it off altogether.

Repair and Replace Battery Elements of an Electric Screwdriver

It should be noted initially that all types of batteries can be repaired, both nickel-metal hydride, and lithium-ion. About how to repair the battery of an electric screwdriver, not many people know, so very often it is faulty batteries that become the reason for buying a new tool.

It is not possible to repair a battery that does not hold a charge, so it will have to be disposed of after removing it from the circuit. To repair a battery for an electric screwdriver, in which more than 4 defective banks are found, is irrational. In this case, it is easier to buy a new battery as a whole, or to find a second-hand device.

In conclusion, it should be noted that most screwdrivers are equipped with two batteries, so if one fails, then at the time of its repair will have to use more intensively the second. This will not let the tool lie idle, and you can try to repair the product at a convenient time.

List of tools needed

The following tools may be needed for repair work:

• Multimeter. This tool is needed for measuring AC and DC voltage.
• Screwdrivers and flat-blade screwdrivers. Needed for disassembling the body of an electric screwdriver.
• Soldering iron. The inexpensive models with a power of about 40 W are suitable for repair.

For more information! To use a soldering iron, you will need supplies like solder and tin.

How to recover the battery capacity of an electric screwdriver: reflashing the nickel-cadmium batteries

It makes sense to use this method only when the most unpleasant thing has not yet happened to the power supply. its drying out. If all the signs of this phenomenon are present, you can only throw it away. It is possible to understand the state of the electrolyte of such batteries by carrying out the following experiment with them: if after charging they also show no signs of life, then it can be concluded that the cells are dry.

If you managed to restore the performance of the battery, then it will be a great success for you. If we talk in more detail about the technology of solving this issue, the restoration of the electric screwdriver battery is the impact on its elements with current and voltage of a significant rating.

• First it is necessary to disassemble the battery and subject each of the constituent elements to charging.
• After that, it is necessary to connect to the cells the charger, which has a significant power. You can also use a car battery charger for this purpose, provided that it has voltage and current regulators.
• The next step is to set it up. It should be borne in mind that all the battery cells of an electric screwdriver has a voltage charge of 1.2 V and a small amperage rating. It is important for us that each single battery pack has 3 times the voltage of the original battery.
• After that you can start charging, but its duration should be small, usually not more than 3-5 seconds.
• At the end of this procedure it is necessary to measure the changes with a multimeter. If the device shows that the final voltage of each cell is at the moment 1.4V or so, we can rejoice because we have achieved our goal. The battery may then be reassembled in the reverse order and used for its intended purpose.

Sometimes the desired result is not obtained after repeatedly charging certain cells. In this case the only thing left to do is to throw them away. We will have to replace worn out cells with working batteries. I’d like to repeat once again that the described method is effective in the fight against the memory effect, which have nickel-cadmium batteries. If the battery has exhausted its resource, this method will be ineffective.

How to repair the battery for an electric screwdriver: fault detection and repair

How to repair the battery for an electric screwdriver. this is a frequently asked question among home masters, because this device is available in the arsenal of almost every owner. The main advantages of battery-powered tools are their compact size, the ability to work with them even at height (due to the lack of power supply wires). Nevertheless, the battery of this device can fail, and it is not profitable to buy a new one, because its price sometimes reaches up to 60% of the cost of the tool. Therefore, it is recommended to try to restore the battery. how exactly, we will tell you today.

How the battery of an electric screwdriver looks like?

Despite the variety of models of these tools, the battery of all the screwdrivers has a similar appearance. It is a box made of plastic, which contains many constituent power cells. They are wired to each other in a single circuit so that the wires of the “cans” on both sides are shorted to the contacts that supply power to the screwdriver.

All batteries have a primitive design that even an inexperienced technician with little knowledge of electricity can understand. In addition to the power parts, the unit box often contains the power elements: