Comparison Bosch UniversalPump 18V (0603947100) vs Bosch EasyPump (0603947000)

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 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.

The length of the hose through which air is pumped into the tyre. The larger it is, the more convenient the device is to use. But it is rare that the compressor is left far from the wheel, especially if a pressure gauge is placed on the device, which must be periodically checked. For domestic use in cars, a one and a half metre long hose is enough. Powerful and performant models can be equipped with a hose of 7 metres or more, but these are more solutions for commercial use in car services.

The presence or absence of a battery supplied with the corresponding compressor. This item may also indicate a built-in battery.

Models with a removable battery are usually produced for a specific battery platform (see the corresponding paragraph). The advantage of this solution is obvious: first of all, it allows you to use the same battery both to operate the compressor and for another power tool supporting a similar battery platform. For normal full operation of the device right out of the box, 1 battery is enough. The option without a battery becomes relevant if the customer wants to choose a power source separately, or when such a source is already on the household.

Many compressors are equipped with a built-in battery. This design saves the customer from fiddling with a separate charger, but does not allow you to quickly replace a dead battery with a fresh one - the only option is charging, which requires a power source and takes some time. However, models with a built-in battery are often more compact, which benefits them exclusively for future use.

The nominal battery voltage for which the cordless tool is designed.

Manufacturers select battery voltage taking into account the operating characteristics and the power supply required to achieve these characteristics. In practice, this means that most often you can not pay attention to this parameter at all when choosing. The only exceptions are some specific situations - for example, if the “household” already has a battery from the same company and you want to evaluate its compatibility with the selected model, if the selected tool comes without a battery and you want to immediately order a power source for it, or for accurate comparison of batteries by capacity. But after purchase, voltage data can also be useful for searching for chargers in addition to or as a replacement for the “native” charger.

In theory, the higher the capacity, the longer a cordless tool can last on a single battery charge. However, in practice, everything is far from so simple. Firstly, ampere-hours are a fairly specific unit; its features are such that only batteries with the same voltage can be directly compared by the number of ampere-hours. If there is a difference in voltage, you need to convert the capacity into watt hours and use them for comparison. Secondly, the actual autonomy of the tool depends not only on the properties of the battery, but also on power consumption and other performance characteristics. Thus, it is possible to compare different models in terms of battery capacity only with the same supply voltage and similar capabilities.

Ability to operate in power bank mode. This feature is found only in models with built-in batteries: it allows the battery to be used for charging/powering a smartphone or other external gadget. Thus, a compressor with a Power Bank function can serve as an additional external battery, which can be crucial during power outages. The design may include both a USB-A port and a more modern USB-C port.

Function that automatically stops operation when a sufficient level of tyre pressure is reached. Usually, the pressure at which the auto-stop is triggered can be set at the discretion of the user.

This function greatly simplifies the work with the pump: the risk of overfilling the tyre is reduced to almost zero, while the user does not need to monitor the pumping process, because the pump will stop at the right time. On the other hand, hitchhiking significantly affects the price. It is found only in electric compressors (see "Type").

Many pumps/compressors come in special cases or cases that make them easy to store and transport. Under the cover, usually, we mean a classic cloth bag, which pumps are often equipped with and which rather protects them from dirt, dust, etc. But compressors are often supplied in plastic cases, they are convenient, inexpensive, rust-resistant and equipped with a convenient carrying handle . Plastic is considered less durable, but it is quite enough to provide the necessary protection.