For all devices of battery type, including a screwdriver, there is a significant drawback - limited battery life.
Scheme of the device cordless screwdriver.
That is why before each owner of such a tool at any time may be such a question as the replacement of batteries in the screwdriver. But before proceeding to action, it is necessary to understand the variety of batteries and their features.
Types of power tool batteries
There are a huge number of technologies for the production of batteries, but the most common and popular among them are the following:
- Lead-acid batteries are most popular for automotive manufacturing due to ease of manufacture and low cost. But then, for use in power tools, they didn’t show themselves much, because they have low power with large dimensions and heavy weight.
- Nickel-cadmium batteries significantly outperformed lead-acid cells. After all, they are with a small weight and compact size give more power. But, of course, there are some negative aspects, in particular, battery toxicity. Since the production of this kind of battery cells brings harm to the environment. For example, in the European Union countries, this type of battery is considered prohibited.
- Nickel-metal hydride cells are considered a more advanced version of the previous type of battery. After all, they are completely safe for the outside world. But there is a drawback in the form of high rates of self-discharge current.
- Lithium-ion batteries, although they have almost ideal parameters, since they have high capacity, small size and low weight, they are not very popular. This is because such a progressive element has a high cost, and therefore not affordable for every man in the street.
What is a battery screwdriver?
Charger circuit for the screwdriver.
Any battery is presented in the form of a small number of batteries, in other words, cans. The latter at most have standard dimensions. A distinctive feature of such batteries is their SUB-C capacity.
The battery is characterized by the presence of four main contacts:
- Through the power contacts, of which there are two units, pass currents in the process of charging and discharging the entire battery of the screwdriver.
- At the top there is always a control contact that is continuously connected to the disconnecting thermal sensor and is used to prevent the tool from overheating during charging. because at this moment the device absorbs the currents of a huge nominal.
- The last but no less important contact is called service. It is used to equalize the charge in all banks at the moment of the deepest discharge in the most structurally complex battery cells.
How to calculate a non-working battery cell?
The composition of the battery.
Since the battery is presented in the form of a certain number of cans interconnected, a current flows through it completely. To find a non-working battery cell, you must initially fully charge the entire battery until it is clear that charging is over.
Further, it is recommended to measure the voltage on each individual bank. The voltmeter should not show values below 1.2 volts. If such indications are present, it means that the battery cell is not receiving proper power or is not charging.
Important! In order to make sure of your measurements, it is necessary to put a mark on the doubtful element and back to make the assembly.
So, after several periods of tool operation, it is necessary to reunite the banks again and measure the voltage. Practice shows that the previously mentioned bank will have even less stress than before, because it starts to lose its efficiency and “slow down” the screwdriver.Back to table of contents
The steps for replacing the battery in a screwdriver
The electric circuit of the screwdriver charger.
Considering the fact that in the post-Soviet space the tools of a nickel-cadmium type battery of the screwdriver are most often used, this option will be considered in more detail using the example of a Bosch GSR 14 4 ve-2 professional screwdriver. In our case there will be a complete replacement of the elements of the individual batteries of the screwdriver.
- Remove the cover and remove the battery cells in the assembly.
- Loosen several bolts on the upper red housing.
To get started is to disassemble the battery screwdriver. It consists in the following:
- Prepare new battery cells.
- Next, you need to put tin on all banks on one side and carefully solder the soldering points with distilled water.
- To connect each battery cell of the screwdriver, you can use a previously tinned piece of copper foil. At the same time at its edges it is necessary to make U-shaped notches for further soldering.
- So, attach the foil with a U-shaped cut to the contact of the battery, which was previously applied to the rosin in a liquid form, and solder. After a few simple manipulations, all elements of the battery will be assembled and ready for replacement.
- Install the assembly in your own box screwdriver. Done!
Types of recovery of previously used battery cells
Diagram of the device lithium-ion battery for the screwdriver.
Very often, a method of resuscitation of previously used batteries is used, because during the operation of the screwdriver, in other words, during constantly high loads, some elements lose their tightness and become unusable. In this case, it is necessary to make a short time impact of a high current on the required battery cell (bank), and it may be possible to resume the battery performance.
You can also try to gently squeeze or slightly deform the body of the screwdriver battery. Since it is possible to prolong the battery life for a short time. But in most cases, this method does not guarantee the duration of the battery screwdriver and is temporary.
Nickel-cadmium batteries are characterized by considerable endurance, since they can not lose their charge for a long time or they can be discharged, but very slowly. But in the case when it was not possible to restore their working capacity, it is worth making a process such as replacing the batteries in the screwdriver device.Back to table of contents
If during replacement of the battery cans old and new elements were used at the same time, it is necessary to equalize their charge. To do this, you need to prepare a charger that will not turn off after a certain period.
Important! The process of active charge must be performed about ten hours.
After which the battery of the screwdriver should cool down to ambient temperature. In this case, in no case forced to cool the banks is not recommended. Everything should happen naturally, without outside intervention.
Next, you need to ensure the maximum level of discharge of the screwdriver battery. But there is a small nuance. It is necessary to control the heating of the battery to prevent overheating. After all, all work will be done in vain.Back to table of contents
Screwdriver Battery Memory Effect
Table of characteristics of screwdrivers.
Very often, in the process of using a screwdriver, they forget about the rules and recommendations for its operation. That is why the batteries lose their charge at the wrong time for this. At this point, the battery cells instantly catch the memory effect and lose their former performance.
Of course, there are such tools that provide the correct charge algorithm. It implies the mandatory discharge of batteries to readings at a rate of 1 volt per individual cell. This can occur either after pressing a certain button or in automatic mode, but it happens that this does not eliminate the memory effect.
Although in most cases, the elimination of this effect after such a process as battery replacement is performed by repeatedly discharging and charging the battery cells in the screwdriver. At the same time it is not even necessary to work with a power tool - you can simply use a light bulb. She will slowly, but successfully cope with this simple task and completely discharge the battery banks.
So, the work of the screwdriver sooner or later lead to the fact that its batteries will become unsuitable for work. It is recommended to choose from several solutions to the problem. After all, if you wish, you can completely replace the battery assembly, replace the worn out cans, or try to restore those elements that confuse you.
But in this case, it should be understood that a complete replacement of the screwdriver battery is almost equal to the price of a new power tool.