Glossary
SMA Solar Technology AG
170
SBU2200-TEN083320
Technical Description
25 Glossary
Absorption Phase
Constant V phase: A charging phase using constant charging voltage. The charging current constantly
decreases in this phase.
AC
Abbreviation for "Alternating Current"
AC Coupling
The connection of various loads, generators and storage devices on the AC side.
AGM Battery
Absorbent glass mat separator battery. This is a battery where the electrolyte (a mixture of water and
sulfuric acid) is bound to a glass fiber mat, a type of closed lead acid battery. A gas mixture
(hydrogen and oxygen) is always generated when lead acid batteries are charged, and in normal
operation this is internally recombined 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 “maintenance 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 - when two separate charges are connected.
Automatic Disconnection Device
The "automatic disconnection device between a grid parallel power-generating system and the public
low voltage grid" is an equivalent replacement for a normal public disconnection device with isolation
function which is accessible to the distribution grid operator at any time. This is a mandatory safety
device which prevents energy from a solar power system being fed into an external power grid when
the external power generator is not functioning. In the Sunny Boy / Sunny Mini Central, this function
is performed by the “SMA grid guard Version 2”. With Sunny Backup 2200, it is integrated in the
Automatic Switch Box.
Automatic Switch Box
Switching device which switches a Sunny Backup system between grid operation and stand-alone
grid operation. In the Sunny Backup system, during grid operation a PV system is operated via an
automatic disconnection device at its own feed-in counter; upon grid failure, it is switched to the stand-
alone grid which is disconnected from the public grid. As an option, the box can also integrate a
diesel generator into the Sunny Backup system.
Backup System
Backup systems are power supply systems which provide an extra level of security for standard power
supply systems. The public grid is usually the standard power supply system, which is backed up by
an additional stand-alone grid system in 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.
