2023 Author: Philip Bishop | [email protected]. Last modified: 2023-05-24 22:24
- The main parameters of the battery and the tool itself
- Which battery is better lithium or nickel-cadmium
- Ni-MH batteries
- Lithium ion (Li ion). The most advanced batteries
- Selection features
When choosing a screwdriver suitable for specific tasks, it is worth paying attention to various characteristics. Among them, the most important are not only the power of the device and the capacity of its battery, but also the voltage of the battery, and even the value of the torque.
When carrying out construction and repair work, a screwdriver is an indispensable tool that simplifies screwing various types of fasteners, and sometimes even drilling holes. And, despite the fact that there are two versions of this device - mains and rechargeable, more often it is the last option that is chosen to perform everyday tasks. At the same time, attention is drawn to the parameters of the power tool itself and to its characteristics such as the voltage in the screwdriver, its power, torque and battery capacity. Each of these indicators is important for assessing and choosing the right device. While buying because of just one suitable power or voltage is not worth it.
The main parameters of the battery and the tool itself
The main parameter that characterizes the operation of a screwdriver is the voltage of the battery, which, in turn, determines the power of the electric motor and the torque. For household models, the difference in voltage between screwdrivers is small - on average, it is in the range of 10.8-14.4 V. More productive options designed for permanent use can be equipped with batteries of 24-36 volts.
The voltage of the screwdriver's battery depends on the type of battery - you can answer what the difference is, knowing what metals were used to make it. For nickel-cadmium batteries, large in size with a similar capacity, the value of the indicator is a multiple of 1.2 V (this is exactly the voltage for one cell of which the battery pack is made up), for lithium-ion batteries - 3.6 V.
Other equally important characteristics include:
- torque, the value of which can become one of the main answers to the question of what the battery voltage of a screwdriver affects. By this characteristic, it is possible to determine both the diameter and the length of the screw to be screwed or self-tapping screw. Large fasteners, as well as drilling deep and wide holes and hard materials, also require a serious torque value. Torque - 12-15 Nm (maximum up to 30 Nm) for home models, 30 Nm for professional ones. The parameter is important, pay attention to it.
- If the maximum speed is less than 1000 rpm, it will be convenient to use the tool to tighten screws and drill soft materials (wood, metal, plastic). If you are going to drill metal, choose models with rpm above 1500 rpm. They will have two speeds: the first is for fasteners, the second is for drilling.
- For serial work (installation of drywall sheets, clapboard cladding), choose corded screwdrivers with a depth gauge. For work at home, both network and battery models are suitable, so choose what you like best.
There are two types of screwdriver torque - starting (larger in magnitude and required to start the device into operation) and constant, that is, working. The parameter value for modern equipment models can be adjusted - to find out how many modes can be selected for a particular device, you can find out in the documentation available for it. Moreover, tools with a pulsed mode of operation (turning on the rotating part by jerks) have more screwing capabilities - by periodically increasing the torque, they can screw in a larger screw.
The output value of the torque from electric motors is not constant and depends, first of all, on the speed of the motor, the higher the speed, the lower the torque on the shaft.
In addition to the voltage of the screwdriver and its power, the capacity of the battery should also be evaluated. The characteristic is measured in ampere-hours or milliampere-hours. The higher the indicator, the longer the screwdriver can work without recharging.
The average battery capacity of the household model is 1300 mAh, which is enough for 2-3 hours of operation. Professional equipment requires more time to complete the work - and a master who uses a screwdriver for a whole working day should purchase a model with a battery already from 1.5-2.0 Ah or more.
Which battery is better lithium or nickel-cadmium
This question about which battery is better for a screwdriver is not entirely correct. It all depends on the situation and on the length of time during which the tool will be used.
The variety of storage batteries is due to the fact that various chemical elements can be used as electrodes and electrolytes. The quality of the power tool used depends on the correct choice of energy storage. The most widespread in the field of electrical appliances are the following 3 types:
- nickel-cadmium (Ni-Cd);
- nickel metal hydride (Ni-MH);
- lithium-ion (Li-Ion); lithium polymer (Li-Pol).
The lithium battery pack weighs less for the same capacity as cadmium. But this is not the main indicator based on which you should choose a battery for a screwdriver.
Of course, the number of charge-discharge cycles for cadmium cells is several times less than for lithium ones. The standard for Ni-Cd is 500 and for Li it is 1500, which certainly first suggests that lithium batteries are much better and lighter in weight.
When choosing batteries, it is important to consider the fact that the aging of nickel-cadmium batteries depends solely on the cycles they have developed, and not on their actual age!
The service life of lithium-ion batteries, unlike cadmium, directly depends on the age of the years. After 3 years, they will be out of order, even if they have not been used.
Nickel-cadmium batteries, on the other hand, will last a long time even if they are rarely used.
For example, when buying a used screwdriver, you should not take it with lithium batteries. There is a high degree of probability that if the tool has not been used for a long time, or has been subjected to frequent freezing, its battery pack is already unusable.
If the bu "Shura" is sold with cadmium batteries, they can save up to 60% of the charge, regardless of whether the tool was working or not.
If the screwdriver is not used very often, lithium batteries will “age” rather than serve their intended 1500 cycles. Therefore, for periodic household use, it makes no sense to buy a tool with lithium batteries.
Cadmium can last 3 to 5 years, whether batteries are used or not. It can also lie quietly in the warehouse, keeping its properties, unlike lithium. Unless you plan to use a screwdriver often, the answer to the question of how to choose a battery is short and truthful: choose cadmium.
By the way, at temperatures down to -20 ° C, cadmium "behaves" better than lithium batteries, which do not like severe frosts. Lithium should be kept at least 60% charged. They need constant recharging when not in use. Otherwise, they start to break down.
Thus, it becomes clear that nickel-cadmium batteries, in fact, are no worse than lithium ones. The main question is only in the field of application of both types of chemical nutrients.
When used at the right time and in the right place, both can be equally useful and good.
Nickel-metal hydride batteries are less common than nickel-cadmium batteries for screwdrivers.
Their advantages include the absence of toxic components, environmentally friendly production, an insignificant "memory effect" and less self-discharge than nickel-cadmium batteries.
In addition, when compared with Ni-Cd rechargeable batteries, nickel-metal hydride batteries have a large capacity and withstand a greater number of charge-discharge cycles.
Ni-MH battery has the following advantages:
- they practically do not have a memory effect;
- no toxic components are used in their production;
- ease of disposal; capacity is 30% more than that of nickel-cadmium; lightweight and compact; are not afraid of mechanical damage.
- take a long time to charge; 500-600 charge-discharge cycles;
- after 300 cycles, a decrease in capacity can be observed;
- cannot be operated at negative temperatures;
- cannot be completely discharged; higher cost in comparison with the previous type.
Store nickel-metal hydride batteries half-charged and cool.
Lithium ion (Li ion). The most advanced batteries
When thinking about how to choose a cordless screwdriver, we note that the most modern lithium-ion batteries also have their pros and cons.
Let's list their advantages:
- light weight and dimensions;
- specific capacity is twice that of Ni-Cd;
- no memory effect;
- a large number of charge-discharge cycles (up to 700);
- low self-discharge: (3-6% per month);
- ease of maintenance (do not require strict adherence to charge and discharge modes);
- fast charging (30-40 minutes on average).
They also have disadvantages and they are quite serious:
- Do not work at negative temperatures;
- Are not restored;
- Low “lifespan” (maximum 2 years). Moreover, the age of the battery is counted not from the moment of the start of operation, but from the date of its production (therefore, buy only "fresh" ones).
- Explosion hazard and fire hazard;
- A complete discharge will damage the battery (attempting to recharge it may cause an explosion);
- Sensitivity to overheating and shock;
- High price.
Another important nuance that you need to remember is the storage of the cordless screwdriver. Nickel cadmium batteries can be stored discharged. Nickel-metal hydride, on the other hand, must be fully charged before long-term storage (several months).
Lithium-ion batteries need to be said separately: they don't care whether you store them charged or discharged. However, remember that they age quite quickly. Therefore, buy a tool with such power sources not for one-time work, but for intensive use. After 1 year, the lithium battery will lose about 30% of its original capacity, and after 2 years the battery will have to be discarded.
As you know, professional screwdrivers are more expensive, but this is not accidental. They are made with a large margin of safety, for which higher quality and more expensive materials are used. In addition, they have more power, which makes it possible to screw in longer screws and / or work with tougher materials.
To decide a household or professional screwdriver you need, estimate the amount of work that will need to be done. If you are starting a construction or major renovation, you probably need a professional or semi-professional model. If the tool is needed periodically - to twist / twist something from time to time, everyday life is more than enough. With such work, the resource of a professional tool will simply not be in demand. So choosing a screwdriver by this criterion is not very difficult.
When choosing a power, it is worth taking into account not only what power of the screwdriver is indicated in the information from the manufacturer. Due to the high performance, the device can tighten the screws too hard, pushing their head into the surface. As a result, the appearance of the coating deteriorates, and the fasteners, if necessary, are almost impossible to unscrew.
When choosing which voltage is best for a screwdriver, it should be borne in mind that voltage is the main parameter of the device. So, for example, the motor power of the Makita DDF343SHE screwdriver is 700 W, with a voltage of 14.4V and a battery capacity of 1300 mAh and a torque of 36 Nm. Whereas the other Hammer ACD182 model has a weaker motor (22 Nm) and a not so capacious battery (1200 mAh) - and it seems that this device is about 40% weaker. However, due to the 18 V voltage, the Hummer is able to tighten more fasteners without recharging, even yielding to a competitor in terms of battery capacity.
To understand why a less productive screwdriver at first glance is inferior to a more powerful one, you can, after a small calculation:
- the amount of energy stored by the first model is 1.2 x 1.8 = 21.6 Wh;
- the second indicator is only 1.3 x 14.4 = 18.72 Wh, i.e. 15.4% less.
In the process of choosing a screwdriver, it is advisable to take into account the presence of a spare battery in the kit. Some models even have 2 extra batteries. On the one hand, such a complete set will cost more (especially since the cost of the battery is up to 80% of the price of the equipment), but it will be much more convenient to work with it. At the same time, an additional battery is not needed to perform household tasks - the time of work performed with its help rarely exceeds 1–2 hours. Whereas in the process of constant use of a screwdriver (for example, for repair work or assembling furniture), the second battery allows you not to interrupt work for more than a few minutes. The discharged battery is charged, and the spare is installed in the device.
In the absence of the need for lengthy work, for which a screwdriver may be needed, buying a model with additional batteries is not recommended, not only because of its increased cost. It's just that the operating life of such a battery is short, and after a couple of years the user will have to buy a new part without even spending half of the resource of the old one.
Don't try to get the most powerful tool. With excess power, you will screw in the screws too hard, the head will be deeper than the surface, which spoils the appearance and makes it difficult to unscrew the screws if necessary.
Before choosing which power of the screwdriver is right for you, you should decide for what purpose the tool will be used. For rare use in a home workshop, a simple low-power tool is suitable, with a voltage of 12V, a capacity of 1.5Ah and a maximum torque of 25Nm. With such a tool, you can work when assembling furniture and screw in small self-tapping screws for attaching home furnishings (curtains, paintings, etc.).
Always try to choose a screwdriver with 2 batteries included, as batteries are an expensive replacement part.
It is worth noting that the power of the screwdriver battery, although it is an important parameter when choosing a suitable model, is much more important than the voltage, capacity and type of battery. And it is often worth paying attention to the torque only if it will be used not only for screwing in, but also for drilling. You should also know that the maximum power of a cordless screwdriver of all commercially available models has a device with a voltage of 36 V, a torque of 60 Nm and a capacity of 3000 mAh. Such equipment is rather difficult and not very convenient to use on a daily basis without professional experience. And, therefore, you should opt for less productive options produced by well-known and reliable brands such as Bosch, Hitachi, Makita, AEG, Dewalt and Metabo. Even if you buy a screwdriver with insignificant characteristics, these models of screwdrivers will last for many years.