How to choose a cordless tool: professional recommendations

Recommendation points

• Battery
• Which battery is better
• Choosing the power characteristics of the battery
• Charging the cordless tool
• Complete set of cordless tools
• Motor and something else
• conclusions

Our new article is for those who are seriously thinking about purchasing a cordless instrument. Stay with us and you can easily choose exactly what you need. We will try to answer all your questions, we will tell you about the features of battery machines, talk about their advantages and disadvantages, and, of course, we will compare them with network counterparts.

Install at a height, often change the workplace during the day, do something in the “field”, work in the country, at de-energized objects or where the power supply does not meet the standards – it is quite natural that such tasks cause certain difficulties for the contractor … Citizens workers have long dreamed of having truly autonomous and at the same time efficient machines in their arsenal, but help came only very recently. Ten or fifteen years ago, wireless technologies belonged to the category of “niche”, and the main “patient” for them was the screwdriver. No, there were, of course, other tools powered by mobile power sources (for reference, the first such hammer drill appeared in 1984), but they were seriously inferior to their network counterparts, both in performance and in many other respects. It all came down to the imperfection of the batteries. The capacity of the blocks was small, they took a long time to charge, the torque and speed were weak, the large weight and the solid price of the unit also did not inspire optimism. It is not surprising that many masters for a long time treated him only as self-indulgence..

Bosch GBH 14.4 V-LI Compact

A bit of history for statistics lovers. Nickel-cadmium batteries were invented in the last year of the nineteenth century. In 1961, man flew into space and the world hardly noticed how the first cordless drill appeared. In the late seventies, nickel-metal hydride units were developed to replace NiCd batteries. And by 1991, some technical problems were solved, and the most progressive Li-Ion batteries began to be used more or less actively, despite the fact that they were invented back in 1912.

And now, the ice has broken, at last the works on improving the autonomous power supplies have borne fruit. This is noticeably in advance of the auto concerns that produce electric cars, which, without waiting for the complete depletion of oil reserves, invested billions in the development of lithium-ion technologies. The progress turned out to be so serious that instrument manufacturers are now loudly voicing the technical characteristics of their products (they used to be silent about the power of wireless models). In the catalogs of leading companies, there are several tens of names of mobile units. Moreover, this list includes previously simply unthinkable tools for him – construction vacuum cleaners, metal scissors, pistols, grinders, powerful SDS-max punchers, circular and reciprocating saws, vibrators, grinders, jigsaws, staplers and nailers, impact drills and wrenches … plus lights, screwdrivers, radios for builders and other nice little things. The Shtilevites are already selling cordless chain saws with a 30-centimeter tire and scythes / trimmers, and the Kress developers have issued a revolutionary super perforator to the mountain, which can be powered both from autonomous blocks and from the network. Particularly zealous companies declare their intentions to adequately duplicate all their tools with battery versions. And most likely, they will succeed, since already at the moment some wireless models are not inferior to network models in terms of power.

Metabo W 18 LTX 125 Quick

Many of the former skeptics, who had a chance to work at least a little bit with a modern cordless instrument, have become its loyal fans forever. Wireless models are now lighter, more powerful, cheaper, they are able to fully satisfy the wishes of seasoned professionals, and even more simple home craftsmen. As usual, the user will have to understand the details to select the right machine. Well, that’s what our article is about..

Battery

When we talked with you about the performance of various network tools, the main focus was on the characteristics of the motor. In the case of a battery-powered tool, the same issue must be considered as a whole (battery – motor – transmission – charger – equipment), and the indicators of an autonomous power source come to the fore.

Which battery is better

Today, three types of batteries are used: lithium-ion, nickel-metal hydride, nickel-cadmium. These are not just separate types of power blocks, they are different technologies, each of which has its own pros and cons. Let’s take everything in order.

Nickel-cadmium Is an honored veteran who has served us faithfully for over 50 years. Due to their undeniable advantages, NiCd batteries have not lost their relevance even now. First, they are inexpensive. Secondly, such batteries can be operated in a wide temperature range (from -20 to +60 degrees). Third, nickel-cadmium blocks can be discharged at high currents and quickly charged without being too hot. Fourth, they are designed for a large number of charge / discharge cycles (1000-1500). The disadvantages of NiCd batteries include the famous “memory effect”, which consists in reducing the capacity of the battery pack if it is put on charge until it is completely discharged. Note that service centers are successfully fighting this scourge (memory), restoring seemingly dead NiCd and NiMH batteries. The next disadvantage is the high toxicity of the elements of the nickel-cadmium block. Due to the fact that it is very difficult to dispose of such batteries, they have already been banned in the European Union, it is only a matter of time before this happens in other countries. It is the high environmental requirements that led to the emergence of nickel-metal hydride batteries..

NiMH batteries solved the problem of utilization and even turned out to be about 30% more “capacious”, respectively, 30% lighter and more compact than their predecessors (with the same power indicators). There is no “memory effect” in the new blocks, to be precise, almost absent. A few spoons of tar were found in the honey barrel:

• fewer recharge cycles (up to 500-750)
• the degree of self-discharge has increased by one and a half to two times
• the unit gets very hot when charging
• charging takes place at lower currents – longer

It is worth noting that some of these problems have already been solved (or minimized) by leading battery companies. And most importantly, work in this direction continues. It is difficult to say exactly which of the many manufacturers has achieved what results at the moment (they have different successes), especially since the situation is changing very quickly. But, having these four points, you know which nuances you should pay special attention to..

Lithium-ion batteries are rightfully considered the most progressive. The “memory effect” is not observed, the battery stores and gives out much more energy (the capacity of one cell reaches 4 Ah), the voltage (up to 36 V) and electric density (up to 200 Wh / kg) have increased, there is practically no self-discharge ( up to 5%), lighter weight and dimensions with similar energy performance, charging time was reduced to 60-30 minutes. To put it quite simply – then, comparing with NiCd and NiMH, everything is more fun about 1.5–2 times. It is precisely these two times that Li-Ion batteries are more expensive than their older predecessors. The relatively high price is predetermined by some technical difficulties and the use of serious control and monitoring systems: protection against deep discharge and overcharging, protection against overheating and current overloads, indication of the remaining charge. Due to the high resistivity, lithium cells get very hot during charging, so they are “packed” in housings made of materials that dissipate heat well, equipped with special rods, as well as channels / holes for forced ventilation.

Note that different manufacturers of lithium-ion batteries use a different chemical formula for their products (about 3-4 variants are widespread), so their power supplies have different performance characteristics. We can say that all children’s problems related to functionality (fragility, fear of deep discharge, problems with subzero temperatures, overheating, etc.) have been successfully resolved, everything has moved towards increasing energy consumption and reducing the cost. Now Li-Ion batteries are supplied not only to elite professional models, but also to an amateur instrument..

Choosing the power characteristics of the battery

Let’s take a look at the main technical parameters of batteries that are common to all types of batteries and directly affect the performance of a cordless tool. To them, we primarily include the operating voltage and capacity of the power unit..

The battery voltage (measured in volts – from 3.6 to 36 V) can tell us about the power of the machine – how hard work the tool can do, what can be the maximum torque or speed (frequency). More power in one line is achieved by increasing the number of elements (cells) in the block, while the motors are usually installed the same. This will certainly affect the weight, dimensions and cost of the battery. Therefore, when choosing a device, you should very carefully evaluate the range of probable tasks that you will use it to solve, especially since the lion’s share of the cost of an autonomous instrument can be its batteries. It will not be logical to purchase a heavy 36-volt unit for a home workshop (a similar unit itself weighs about 2 kg), a machine with a 9.6, 12 or 14.4 V battery is suitable here. Many companies focus on tools with operating voltage 18 V, as the most versatile and the most demanded among professionals and amateurs. There is one remark here. If we compare the power of network and similar mobile models, then among the “heavy artillery” (grinders, perforations, circulars …) only 36 V devices are able to compete on equal terms with traditional specimens with a capacity of about 1000 W and slightly higher. As for drills / screwdrivers, in this class of tools, machines with 18 V blocks are also capable of adequately resisting. In the case of weaker batteries (14.4 and less), perhaps any comparison of capacities will be in favor of the “networkers”. As we said, some manufacturers directly (in watts) indicate the power consumption of their wireless machines.

The battery capacity indicates how long the tool can operate on a single charge. This characteristic of a wireless device is always indicated on the battery case and averages about 1.2-3 amperes per hour, and more recently, even more capacious units have appeared – 4 Ah. It is worth noting that we are talking about the energy capacity of a single battery cell. Therefore, do not be surprised when you see machines with different voltages on the counter, but with the same capacity. The indicator is very important, but it is impossible to judge the performance of the tool only by it, here it is logical to evaluate the machine in the tandem “voltage – capacity”.

Everyone who is just going to acquire a wireless unit and does not have the proper experience is tormented by the same question: how long can a particular cordless tool work continuously. Much depends on the load on the machine. If you calculate mathematically (for this it is good to know the power in watts), then figures of the order of one to several tens of minutes are obtained. It seems a little. However, if we consider that, professionally performing the main types of repair and construction operations, we include no more than 10–20% of the total time with the tool, then this is the total duration of work much more than an hour. For example, a 36-volt hammer drill from Bosch can drill about 200 holes in concrete in the popular 6×40 size on a single charge. Moreover, the power of such a monster is 600 W, and the impact energy is 2.8 J, weight is 4.5 kg.

Husqvarna 536Li XP

So, so that there is no forced downtime, during this time the second unit should already be charged. Easy! It is from these calculations that manufacturers start from.

Charging the cordless tool

As you already understood, the features of the charger are an urgent issue. If it takes too long to charge the battery, then even two blocks may not be enough for smooth operation. If not long ago indicators at 5 o’clock were considered advanced, and budget devices could generally charge up to a day, now chargers that can “restore” the battery of a professional car in an hour, or even in 30 or 22 minutes (DC18RA charger from Makita and a block with a capacity of 3 Ah). However, many household appliances are equipped with a three- or five-hour charger, and this is fully justified by the low intensity of use..

Makita DC18RA charger

Charging a battery quickly can be tricky, as the cells get very hot and can fail if not cooled. Therefore, manufacturers are forced to use batteries of a rather complex design, as well as forced cooling with a fan built into the “charger”. Demanding lithium-ion batteries require more than just a powerful charger, but a smart charger. The Makitovites have introduced an interesting system using computer technology. They integrated a special chip into the battery, from which, during charging, the device reads information about the state of the unit and selects the most optimal “recovery” mode for it (current strength, a certain voltage, degree of cooling), increasing the speed of the process and the durability of the battery as a whole. Many manufacturers are now using microprocessors to control recharge processes, for example, Metabo, after introducing a new technology, offered a 3-year warranty for rechargeable Li-Ion batteries, which no one dared to do before..

Charger Metabo ASC 30-36 V, 14.4-36 V, AIR COOLED

As for other types of batteries, chargers are simpler there, but you need to follow some rules. The main thing is not to keep the battery on charge for too long (do not leave it overnight, etc.). NiCd and NiMH batteries should be charged after a full discharge when the tool starts to lose its “power”. During storage, metal hydride blocks should be recharged about once a month and a half, and after a long downtime, the first daily charge should be made. Nickel-cadmium batteries are recommended to be stored in a discharged state. Almost all modern chargers have at least LED indication, which shows that the battery is fully charged, advanced devices – they themselves gradually reduce currents and stop the process.

Complete set of cordless tools

The truth of life is that good batteries are still quite expensive. We have already spoken about the technological nuances – the production of batteries is a complex and very narrowly focused business. Perhaps, the fact that the overwhelming majority of manufacturers do not make autonomous power plants themselves, but order them from companies specializing in this, also affects. A decent price for batteries justifies the use of one battery in household models (in some cases even a built-in one). However, as far as professional wireless machines are concerned, there must necessarily be two units in the kit or not one (!). Ask how it is? Well, with two units everything is transparent – there is always a stock, which is especially important for a single device in your arsenal. But it makes sense to buy a tool without a battery and charger if you already have another mobile tool of the same company, of the same line. Manufacturers tend to combine different models into a single battery system, in which the power blocks are interchangeable and served by a single charger..

This makes it possible to simplify the task of storing “extra” blocks and significantly save on purchasing a new tool (a bare unit is 70-100% cheaper than what comes with two power sources and a charger). DeWALT offered its own vision of the issue – all batteries of the same voltage, regardless of type, are interchangeable. They have absolutely identical connectors. Imagine buying an 18-volt car with a nickel-cadmium block, you can safely install both a NiMH and a lithium-ion block of any capacity on it..

Motor and something else

When choosing a battery unit, it is worth looking at other points, in addition to the power features of the power source:

1. Pay attention to the type of motor. Many manufacturers use brushless brushless motors for cordless tools. They provide very smooth operation, minimum maintenance, machine durability and high efficiency..
2. Give preference to devices with the maximum range of operational adjustments. This saves valuable ampere hours.
3. Sensitive slip clutches (easy to select the degree of load), as well as an effective run-out brake (quick stop after shutdown) allow to significantly improve comfort and even save energy..
4. Opt for a cordless tool with good shock / drop protection (lithium batteries hate this). An important point is the high reliability of the battery connection, which avoids loss of contact due to vibrations (multi-pin fastening). Usually, manufacturers who have achieved some success in these matters are sure to provide relevant information..
5. If other parameters of the tool do not differ significantly, take a look at the characteristics of the torque (Nm) and the maximum speed of the spindle or tool travel (rpm or stroke / min). This data will tell you about the capabilities of the tool, you can get acquainted with them in the product passport.
6. It is very convenient when it is possible to control the time remaining until the battery is completely discharged. Pay attention to the presence of the corresponding indication.
7. Do not forget about the direct relationship between the power and energy intensity of a cordless tool with its weight and dimensions. Choose the machine according to the expected scope of work.

Makita XOB01 18-volt LXT

conclusions

So, having weighed all the pros and cons of mobile units, we can safely declare the high competitiveness of modern cordless tools. Experienced craftsmen have figured out everything for a long time – wireless machines are actively and very successfully used by professionals on construction sites and by amateurs at home. Overpaying for autonomy, we forever forget about eternally interfering network cables, we have the opportunity to build, even if there is no electricity, we can work quietly “in nature” and in wet rooms, without fear of electric shock. The issues of choosing a network / battery no longer lie in the plane of performance, the main criteria are: ease of use, working conditions and, for now, the state of the wallet.