Glossary - SMA Sunny Island 5048 Installation Instructions Manual

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Glossary

23 Glossary
Absorption phase
Constant Voltage phase: A charging phase using constant charging voltage. The char-
ging current constantly decreases in this phase.
AC
Abbreviation for "Alternating Current"
AC coupling
The AC side connection between loads, generators and storage devices.
AGM battery
Absorbent Glass Mat separator battery. This is a battery where the electrolyte (a mix-
ture of water and sulfuric acid) is bound to a glass fiber mat. This is a type of a sealed
lead acid battery. A gas mixture (hydrogen and oxygen) is always generated when
lead-acid batteries are charged and in normal operation this internally recombines to
form water. This removes the need for regularly refilling the battery cells with water,
which is why these batteries are often described as "low maintenance" or even "main-
tenance free". AGM batteries are available from many different manufacturers for a
wide range of applications. They usually have very good high current properties but
are not very charge-cycle resistant.
Ah
Abbreviation for "Ampere hours". Unit of electrical charge, one ampere hour is the
charge provided by a constant current of 1 A over a period of one hour.
Backup system
Backup systems are power supply systems that provide an extra level of security for
standard power supply systems. The public grid is usually the standard power supply
system and the backup system is provided by an additional stand-alone grid in the case
of a power outage. In addition to the backup systems, diesel generators in PV battery
systems are also described as backup generators. Here they perform the same task as
a backup system for the public grid.
Battery
A battery is an electrochemical storage device that can release previously stored che-
mical energy as electrical energy. A distinction is made between non-rechargeable pri-
mary elements (often used in consumer markets) and rechargeable secondary elements
(accumulators). In stand-alone grid systems, lead acid batteries are almost always used
and, very rarely, Nickel/Cadmium batteries are used as secondary rechargeable ele-
ments.
Battery bank
See Battery system
Technical Description SI5048-11:EE4206 Seite 161