Comparison Black&Decker ASI300 vs Belauto BK 45

The presence of two cylinders in the design of the pump / compressor.

This feature is found mainly among compressors (see “Type”). Usually, it is a sign of a powerful performant device: two working cylinders allow pumping twice as much air in one cycle as in a single-cylinder model with the same diameter and piston stroke. This is especially useful when inflating large tyres such as trucks, buses, heavy SUVs, etc. The downside of this design is increased weight and dimensions, as well as increased energy consumption due to additional resistance on the pistons. So it makes sense to pay attention to such devices in cases where high performance is decisive for you.

On the market you can also find foot pumps with two cylinders; they share the same features.

The type of built-in pressure gauge incorporated into the pump/compressor design. Modern pressure gauges differ mainly in the type of scale on which readings are displayed:

— Analogue. A classic pressure gauge equipped with an analogue scale — a round “dial” with an arrow. Such devices are extremely simple and inexpensive, moreover, they are completely autonomous, do not require a power source and can be used in hand and foot devices. However, they are noticeably inferior to digital ones in accuracy: the scale is capable of displaying readings at best with an accuracy of a tenth of an atmosphere, (sometimes up to two tenths or even more), besides, the arrow tends to vibrate when pumped, which makes it difficult to determine the readings. On the other hand, such accuracy in fact is often quite enough, so analogue pressure gauges have been and remain the most popular option.

— Digital. Pressure gauges equipped with an electronic display that shows pressure data. Such devices have high measurement accuracy — often up to hundredths of an atmosphere (or equivalent in other units), besides, they can provide various additional features — for example, hitchhiking (see below) or switching between measurement in atmospheres and and in pounds per inch2. At the same time, digital pressure gauges are much more expensive than analogue ones, the mentioned accuracy is rarely required in fact, and the...electronics require a power source, which makes it difficult to use in non-electric pumps (batteries would be required, and they have a limited operating time). As a result, this variant has not received much distribution.

— Is absent. There are quite a few pumps and compressors that do not have a pressure gauge at all. On the one hand, this does not allow you to monitor the pressure during the inflation process: you have to control the condition of the tyre “by eye”, and to measure the pressure, disconnect the unit and use a separate pressure gauge. On the other hand, such models turn out to be more compact and inexpensive than similar solutions with pressure gauges, and the described pumping procedure, although associated with unnecessary hassle, is generally not particularly complicated and does not present any particular difficulties even for inexperienced drivers.

The maximum pressure provided by the pump or compressor — in other words, the highest tyre pressure that can be achieved using this unit.

In most models, this figure is from 2.5 to 10 atm, and in mechanical pumps (manual and foot, see "Type") pressure of more than 10 atm is practically not found at all. This is due to the fact that even for heavy trucks, the optimal tyre pressure is usually about 5 – 9 atm (depending on a number of parameters — there are special formulas and tables for calculations); and in passenger car tyres, a pressure of more than 2.5 atm is extremely rarely used. However, there are compressors with higher pressure parameters — 11 – 15 atm, 16 – 20 atm and even higher. The meaning of such characteristics is mainly in the "power reserve": a higher working pressure contributes to faster pumping. However, be careful not to over-inflate the tyre and damage it.

The capacity of the compressor (see "Type") is the maximum amount of air that it can pump into the tyre in a minute.

Higher performance reduces the time required to inflate the wheel; on the other hand, this parameter directly affects the dimensions, weight, power consumption and price of the compressor. So it is worth choosing according to performance, taking into account real needs. So, for a “duty” tyre inflation in a passenger car, a compressor with a low operating speed is quite enough — up to 20 L / min inclusive. And if the speed of full pumping is also important for you (for example, after replacing the rubber) — you can choose a unit for 21 – 40 L / min. In turn, models with more solid characteristics — 41 – 60 L / min and more — are intended mainly for heavy equipment like SUVs, trucks, tractors, etc.

Separately, it should be noted that this parameter is NOT suitable for calculating the exact inflation time (even if the exact volume of air in the wheel is known). The fact is that the actual performance of the compressor is always lower than the claimed one: the figures in the characteristics are indicated for free air outlet, and when pumping the wheels, the pumping speed will inevitably be lower due to the resistance of the nipple.

Rated supply voltage used by the electric compressor (see "Type"); in fact, the types of networks with which the device is compatible.

— 12 V. Standard on-board voltage for passenger cars and similar vehicles such as light trucks and many motorcycle models. 12V compatibility is almost mandatory for modern compressors (only a few models are not capable of operating on this voltage). However, note that the methods of connecting to on-board networks may be different; see "Connection" for details.

— 24 V. A voltage of 24 V is typical for on-board networks of heavy equipment — trucks, buses, etc., as well as some powerful SUVs. In compressors, compatibility with this supply is usually provided in addition to 12 V; Pure 24-volt models are extremely rare.

— 230 V. Connecting to a regular 230 V household outlet. Most often, this option is used as a spare, in addition to 12 V — so that if there is a nearby outlet, the compressor can be powered from it without loading the car battery and without wasting fuel on the on-board generator. However, there are models that use only 230 V — they are designed for stationary use in tyre shops, service stations, etc.

— Battery. Powered by a removable or built-in battery, it gives you the freedom to use the compressor and allows you to get rid of its hard wire connect...ion to the on-board car network or a household outlet. However, a dead battery will still have to be charged sooner or later. And in this matter, you can not do without a wired connection. Keep in mind that the battery may not be included in the standard package of some rechargeable autocompressors and will need to be purchased separately.

The amount of current drawn by the compressor during operation. For most models intended for use with passenger cars, this indicator is at the level of 12-14 A. A small current consumption is preferable from the point of view of energy saving, but the performance of the device largely depends on this indicator (see "Performance").

Rated power consumed by the compressor during operation.

This parameter primarily affects the features of connecting the unit to the on-board network through the cigarette lighter socket. Such a socket has restrictions on load power, and these restrictions are different for different cars; and even in the same car, different connectors — the cigarette lighter itself and a separate socket of the same format — can differ in allowable power. However, most of these connectors can easily cope with units with a power of up to 100 – 120 W; but if you get a more powerful compressor, you should clarify the possibility of using it with a specific cigarette lighter (the easiest way to do this is according to the documentation for the car). If the device is planned to be powered through "crocodiles" or from a 230 V socket (see "Connection"), you can not pay much attention to the power consumption.

Also, more powerful compressors, usually, have a greater capacity and/or maximum pressure, but there is no strict relationship here.

Ways of connection to the power supply provided in the design of the compressor (see "Type").

— Cigarette lighter. Connection to a standard cigarette lighter socket (or a separate auto socket of the same format). This method is convenient because the compressor does not need to open the hood. On the other hand, cigarette lighters have limits on maximum power, and in different cars (and even in different sockets of the same car), these limits can vary markedly. See Power Consumption for details.

— Crocodiles. Connect directly to the battery terminals using crocodile clips. This method is somewhat more complicated than working from the cigarette lighter — you need to open the hood and pull the wires to the battery. On the other hand, it allows you to use the power of the on-board network to the fullest without worrying about overloads and the integrity of the fuses, making it suitable for even the most powerful and performant compressors. In addition, the “crocodiles” device can be connected not only to the on-board network, but also to a separate battery; in some cases, this possibility is useful (for example, if the car’s own battery is already running low, but there is a “fresh” battery nearby).

— Cigarette lighter / "crocodiles". The ability to use any of the connection options described above is optional. This provides convenience and al...lows you to choose the optimal format of work depending on the situation. For example, for quick pumping of one or two wheels, you can use the cigarette lighter, but for long-term work, food through the “crocodiles” is better suited.

— Fork. Plug for connecting to a regular 230 V socket (see "Power"). It is used in compressors having only this type of supply.

— Cigarette lighter / plug. Available on both 12V and 230 V models; for the first, a cigarette lighter is used, for the second, a plug.

— Cable (to the battery). Connection directly to the battery using cables with flat terminals, which are clamped into the battery terminals when connected. This design provides a tighter contact than the "crocodiles" described above, but is less convenient when connecting and disconnecting the compressor.

The length of the cord with which the compressor is connected to a power source — a standard car socket DC 12V (so-called cigarette lighter) or directly to the battery terminals. It is believed that the length of the cable should not be less than two metres to avoid inconvenience in operation.