What is a UPS battery

UPS know-how: batteries for uninterruptible power supplies

Anyone who has ever held an uninterruptible power supply, or UPS for short, will remember one important characteristic: weight. In the case of smaller systems up to around 3 kVA, the batteries are usually built into the housing. And because lead-acid batteries are still used as the most important technology, the resulting weight is considerable.

Most customers only know the batteries in the UPS as a cost factor when changing, which is usually due after three or five years. New battery technologies make an important contribution so that the batteries retain their storage capacity for as long as possible and the change cycles increase. However, ambient conditions, charging technology, type of storage and maintenance intervals have a strong influence on the service life and performance of batteries.

Even if a current UPS is crammed with loads of computer technology, battery technology seems to date from the Stone Age. The principle of the lead-acid battery has been known for over 200 years, in 1801 the physicist Johann Wilhelm Ritter undertook the first experiments with batteries based on lead, copper, tin or zinc.

In 1854 the German doctor Josef Sinsteden put two lead plates in a vessel with dilute sulfuric acid. Constant charging and discharging resulted in a lead-acid battery that already had a significant capacity. The chemical reactions taking place corresponded to the processes common today in lead batteries and will be explained in more detail later.

15 years later, the Frenchman Gaston Planté improved the arrangement of the lead plates, which has not changed too much to this day. However, the way to the industrially applicable battery was still long. As with Sinsteden, the electrodes of the Planté battery consisted of lead sheets, which were formed into anode and cathode by repeated charging and discharging processes.

Around 1881 A. C. Faure and E. Volckmar independently developed pasted grid plates that were coated with lead powder and sulfur paste. This gave the battery a high capacity after the first charge. Shortly afterwards, around 1886, Henri Tudor developed the first technically usable lead-acid battery.