Comparison Varta Promotive Black/Heavy Duty 720018115 vs Bosch T5 HDE 725 103 115

— Serviceable. Only classic lead-acid batteries (see "Type") are serviceable: they can be easily identified even externally by the presence of removable caps that provide access to the internal compartments with electrolyte. The latter is a mixture of sulfuric acid and water, and with each charge, some of this water "boils off" (breaks down into oxygen and hydrogen and evaporates). This occurs especially intensively during overcharging or charging at increased voltage. Battery maintenance consists of periodically replenishing the water supply in the electrolyte—without this, the decrease in its level leads to plate damage due to contact with air, which irreparably worsens the battery's characteristics. On average, maintenance needs to be carried out 1-2 times a year (15-20 thousand km mileage for a passenger car), and these periods usually coincide with scheduled maintenance. However, this value may vary depending on the characteristics of both the battery itself and its operation; more detailed information is usually contained in the instructions for specific models. "Refilling" should be done exclusively with distilled water, as even relatively small amounts of foreign impurities can damage the plates.

— Maintenance-free. As the name suggests, such batteries do not require the maintenance described above; this is achieved by several methods, in particular by filling the electrolyte with a reserve f...or the entire service life or using gel (see "Type"). Despite the obvious advantages due to ease of use, maintenance-free batteries have one drawback: they are much more sensitive to deep discharge (capacity decreases), and, accordingly, they are less tolerant of cold and long downtimes.

The form factor describes the general design features of the battery, primarily the way the terminals are installed and their dimensions, as well as the dimensions of the battery itself.

— European. A distinctive feature of European batteries are the terminals, somewhat recessed into the case. Due to this, this form factor is considered safer than the Asian form factor — the risk of a short circuit is lower when the battery falls on a conductive surface or when a metal object hits it. In addition, the terminals themselves are usually made in the form of Euro cones (see below for more details). As for the dimensions, European batteries have more depth and less height than Asian ones. As the name implies, this form factor is found in cars of European manufacturers, mainly passenger cars.

— Asian. Asian batteries are easy to identify by the terminals protruding from the top of the case; also, these terminals can be noticeably thinner than European ones, because. many models use JAP cones (although not all). If compared in size, then the "Asians" are taller and thinner than the "Europeans" (more precisely, they have less depth). This option is popular with Japanese and Korean automakers, and is also quite widespread among trucks.

— American. A rather rare form factor on our roads — due to the fact that cars from American manufacturers are most often delivered to us in the form...of modifications adapted to Europe or Asia; original versions are rare. Lightweight batteries of this form factor have "USA" screw terminals (see "Terminals"), located not on the cover, but on the front wall of the case. At the same time, both “purely American” and combined batteries are produced, which, in addition to a pair of USA terminals on the front wall, also have contacts on the cover that are more familiar to east european drivers. And in cargo batteries of this form factor, the terminals are usually installed on the cover, in the left side location.

When choosing a battery, it makes sense to clarify which form factor is optimal for your car: a discrepancy in this parameter can cause compatibility problems up to the complete impossibility of installing a battery.

In this case, polarity refers to the location of the terminals on the battery. Traditionally, it is named according to the location of the "+" terminal when looking at the battery from the front (or, in the case of side terminals, from the side closest to which they are located).

— + left. In relation to passenger cars, such polarity in the CIS countries is often called "direct" or "ours". At the same time, in trucks (see "Purpose") the situation is the opposite - the left "plus" is the European standard.

— + right. In passenger cars, the right "plus" is typical mainly for European models, for which this polarity in the CIS countries received the unofficial name "euro" or "reverse" (as opposed to the domestic "direct"). In batteries for trucks, everything is the other way around.

— + right/ + left. This marking means that this battery model is available with both right and left “plus” (see above), and you can choose the option depending on the car model.

Note that the above division into “direct” and “reverse” polarity is not absolute, and in any case, before purchasing a battery in your car, this parameter should be clarified separately.

The electrical capacity of a battery, in other words, the amount of energy stored by a battery when fully charged. The capacity value is expressed in amp-hours and indicates the number of hours during which a fully charged battery will be discharged to the minimum allowable charge, delivering a current of 1 ampere to the load. For example, a capacity of 40 Ah means that the battery is capable of delivering a current of 1 A for 40 hours, or 2 A for 20 hours, etc. In fact, a more capacious battery gives more attempts to start the engine, and is also able to work longer at a low load (for example, when powering a car audio system).

The capacity requirements for different transport types differ markedly. So, in motorcycle batteries, it rarely exceeds 20 Ah, the average value for passenger cars is 40-80 Ah (but there are options for 100 Ah or more), and for heavy equipment like buses, an acceptable capacity starts somewhere from 100 Ah. The optimal value of the battery capacity is often indicated by the manufacturer in the characteristics of the vehicle, and when choosing a model by capacity, you should focus primarily on these figures.