Household screwdrivers: restoring the battery with double energy

Cordless drills have long ago and firmly entered our life: they are practically irreplaceable at home and in “field” conditions, everywhere where there is no voltage of light network of 220 V.

Test: Andrew KASHKAROV

Photo 1: The screwdriver: always ready!

Screwdrivers: well and types!

According to the purpose of the screwdrivers are divided into household semi-professional and professional, with a corresponding difference in power and price. Screwdrivers differ from each other by manufacturer, battery voltage, method of battery attachment not all batteries are universal , a set of screwdrivers and heads, and the rotation power of the electric motor. Almost all screwdrivers have a reverse mode: they rotate both to the right – for tightening, and to the left – for unscrewing.

Photo 2: The appearance of a battery for a DWT screwdriver

Screwdrivers come with a vertical battery mount or with a horizontal one, as in the DWT photo. In this case, the battery is attached with a translational motion in a horizontal plane, and thus fits into the slots of the screwdriver housing.

A different way of attaching the battery is used in Bosch, Gelb and other brands – vertical: in this case, the battery is inserted as a clip in the gun – from bottom to top – until it locks.

The screwdrivers are equipped with a 220 V battery charger with one, rarely two batteries in this case one is a backup .

A fully charged battery usually lasts for a day of normal operation. Battery capacity varies with different screwdrivers, and is within 1.2…2,7Ah. Charging time is a weak current of 5-8 hours.

The voltage of the batteries may vary from 6 to 22 V.

Some screwdrivers are charged together with the battery, others require disconnecting the screwdriver from the battery.

Disadvantages of household models: may they lose their memory!

The disadvantages of household screwdrivers can safely include the battery, if it is made on the basis of Ni-Cd. This type of battery has a notorious memory effect.The best way to get the most out of a screwdriver is to use it until the battery is depleted and then fully charge it so it will retain its capacity longer.

But as a result of prolonged use the capacity of the battery decreases anyway this is due to the sulfation of Ni-Cd batteries, which, unfortunately, is inevitable with time .

Always buy power tools with two or more batteries. These kits don’t cost much more, but their functioning time in domestic conditions increases twice.If the screwdriver is used rarely, the battery capacity is reduced and after a year, its active work time from the regular battery will be almost three times shorter. With active operation – frequent use of the screwdriver, it will serve 2-3 years with the regular battery.

In addition to the loss of capacity, the battery of a household screwdriver “threatened” by other dangers. The battery will inevitably get damaged if you use it frequently at ambient temperatures below 0˚C and above +50˚C, as well as in rainy weather and in conditions of high humidity.

And now let’s take a look at the “reincarnation” of the battery

If in time the battery of your screwdriver has lost much of its capacity it needs to be replaced. If water gets into the battery of the screwdriver, it must also be replaced. Water can get into it not only during work or storage on the street by the way, the question of storage is not less important than the use of a screwdriver, but it is described in detail in the user manual , but also in domestic conditions.

With me, for example, there was a case where the upstairs neighbor flooded the toilet, where the tool was stored in a special locker. The battery has become wet and is completely out of order.

Once a month if the battery has been idle you must reconnect it to the Driver and forcibly discharge it by turning on the Driver at maximum idle revolutions. After that the battery must be fully charged with the regular charger. It is not difficult to buy a separate battery for screwdrivers in big cities, but its price in the segment of semi-professional devices will be commensurate with a new screwdriver.

Nevertheless, it is not difficult to try to repair a “used” battery.

To do this, disconnect the screwdriver from the battery and disassemble the plastic housing by carefully removing the cover with a screwdriver. If you damage the latches on the cover when you open it, you will need to secure it with instant adhesive afterward. Under the cover you will find the battery packs connected in series. Photo 3 shows the appearance of a line of daccumulators connected in series to form a 12 V battery.

photo 3: battery – the inside view

Picture 4: Battery – take 2

Store the wrench and the battery in a dry, moisture-proof place keep the wrench separately and the battery separately. To restore the battery will need to replace all rulers affected by moisture or showing signs of corrosion and sulfation – it is a yellow-white powder on the surface, For this they are disassembled and checked each ruler individually.

Functionability of each such element is determined by its internal resistance, for which we will use a simple method.

Find the internal resistance by means of a shunt 5-10 Ohm resistor . Let’s compare the ruler voltage without load and with load as a shunt . Further, using Ohm’s law photo. 5 , calculate the internal resistance of the battery. The smaller the internal resistance of the battery, the better.

photo 5: Ohm’s law in pictures

With a new battery the internal resistance must be within 0.06 Ohm. According to this method it is not difficult to diagnose all the battery cells and determine which ones need to be replaced. Then the battery elements that have not lost their capacity are assembled and wired into the electric circuit of the new ruler.

We assemble the recovered battery, put the cover of the case back and carefully glue it with “supermoment”. After that, the screwdriver will serve for a long time to come.

If you follow these simple recommendations, the screwdriver will serve you for a long time and will save your family budget. And the money saved, as you know – money earned.

P.S. From personal experience with

As for household screwdrivers, I was able to compare the DWT ABS-12E, purchased in 2007, and the Hammer ACD120A manufactured in 2010 . All other things being equal, the first one has served “faithfully” for one and a half year with one battery replacement, the second one is still in good working order, it will be two years in January. Important detail: in my household the screwdriver buzzes quite often: 5-6 full days per month, i.e. about 70 hours of active work.