Connecting The Battery; Dimensioning The Battery - Studer VarioTrack VT-40 User Manual

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VarioTrack
Under no circumstances should PV module inputs of several VarioTrack be put in parallel.
If several VarioTrack units are connected together by the communication bus, it is highly
recommended to make a software update of all components in the system to guarantee
all its functionalities. (see chap. 9.1 - p. 41)
Solar generators may be of various types and be orientated differently. Each VarioTrack will adjust
the optimum point of the PV generator independently of the other units connected to the same
battery.
In multi-unit systems (connected to the same communication bus), all VarioTracks must be
connected to the same battery bank.
When the VarioTrack units are not synchronized, they must be programmed in the same
way and it's recommended to not activate the periodical equalization function.
The equalization can be manually started or will be done by the synchronized units.
In multi-unit systems, each VarioTrack is connected to the common battery using its own
protection device. All other consumers or sources are connected directly to the battery
using their own protection device.
4.4 C
ONNECTING THE BATTERY
The VarioTrack is a device which DC (battery) connection is to be connected exclusively to a battery.
Most of the time, lead-acid batteries with liquid (VLA, VRLA) or gelled (GEL) and AGM electrolyte
may be used. It can be easily configured to create charge profiles that are compatible with these
various types of lead-acid batteries.
The use of other battery types like Ni-Cd, Li-ion or other is possible if the charge profile is
properly programmed, in accordance with the specifications of the battery manufacturer,
in agreement with the battery manufacturer and under the responsibility of the installer.
The use of the VarioTrack connected to any other type of DC source without battery
(buffer) is strictly forbidden and may cause significant damage to the equipment and / or
to the source.

4.4.1 Dimensioning the battery

The battery bank is dimensioned depending on the user's daily power consumption and the number
of days of autonomy required. It is dimensioned in order to reduce the daily discharge depth as well.
In any case, the battery bank must be dimensioned in order to reach a reasonable ratio between
the maximum charging current and the battery capacity. As for lead-acid batteries, the charging
current should be between 0.1 and 0.2 x Cbatt [Ah] (C10) in order to ensure an optimum charge. For
a 65A charger, a battery of at least between 350 and 700Ah is necessary.
The dimensioning of the battery must also take into account the power and the type of charge that
are connected, most often an inverter. For this type of charge, the minimum capacity of the battery
bank (in Ah) may be calculated this way: five times the inverter rated power divided by the battery
voltage. For example, an Xtender XTH 8000-48 inverter/charger should have a battery capacity of a
minimum 7000*5/48=730 Ah (C 10). Due to the extreme overload capacity of the inverter, it is often
recommended that this value be rounded up. An under-dimensioned battery may lead to an
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