Ensuring uninterrupted power supply to consumers ensures smooth operation and prevents possible breakdowns. Uninterruptible power supply is a well-established practice, especially in the computer industry. UPS devices are increasingly being installed in households to ensure the operation of stoves, boilers, pumps and heating systems in general. Car batteries are often used for these purposes, but they are by no means the right choice. For back-up power, it is recommended to use deep discharge cyclic batteries.
By cyclic batteries we mean batteries that are capable of deep discharges and that discharge frequently. We also often use the term DC "deep cycle".
The number of charge cycles of a battery depends on the manufacturing technology and the depth of discharge (DoD). The number of cycles decreases disproportionately with the depth of discharge.
The battery plates in cyclic batteries are usually thicker than in starting batteries, which have thin plates. Manufacturers are installing thicker plates (around 3 mm) in cyclic batteries and lead electrodes that are not porous but solid.
AGM batteries are batteries where the electrolyte is absorbed into the glass wool as a separator (Absorbed glass material). GEL or GEL CELL batteries have the electrolyte mixed with silica and are referred to as "gel" batteries because of this composition.
VRLA batteries (valve regulated lead acid) are better known as lead acid batteries or simply lead acid batteries. Their construction means that they do not require the regular addition of distilled water to the cells to operate, and their low, virtually zero gaseous emissions make them suitable for indoor use. These batteries are often found in UPS systems, alarm systems, electric trolleys, older electric bicycles, toy cars for children, large hand-held flashlights, household vacuum cleaners and similar devices. VRLA batteries are known as AGM and GEL.
VRLA batteries do not require maintenance. VRLA batteries have a specially adapted valve to allow recombination of gases. The safety outlet valve is only opened when the battery is electrically overcharged, otherwise an explosion would occur.
The accumulator is pressurised and the oxygen and hydrogen released are combined in the valve to form water, which is returned to the accumulator. This is why water consumption in VRLA batteries is extremely low.
VRLA batteries are also often referred to colloquially as "hermetic" or "dry" batteries, or in English as "SLA battery". These terms are not accurate, as VRLA batteries are not completely sealed for the safety reasons mentioned above, nor are they dry, as the electrolyte is in a liquid, AGM or GEL state.