Steca Xtender
Installation and Operating Instructions 723.932 Xtender V0.511 Seite 12
4.3 Recommendations for dimensioning the system 4.3.1 DIMENSIONING THE BATTERY
The battery capacity is dimensioned according to the requirements of the user – that is 5 to 10
times its average daily consumption. The discharge depth of the battery will therefore be limited
and the service life of the battery will be extended.
On the other hand, the Xtender must have a battery capacity that is large enough to be able to
take full advantage of the performance of the equipment. The minimum capacity of the batteries
(expressed in Ah) is generally dimensioned in the following way: five times the rated power
output of the Xtender / the battery voltage. For example, the model XTH 8000-48 must have a
battery of a minimum capacity of 7000*5/48=730 Ah (C 10). Because of the inverter’s extreme
overload capacity, it is often recommended that this value be rounded up. An under-dimensioned
battery may lead to an accidental and undesired stopping of the Xtender in the event of high
instances of use. This stoppage will be due to a voltage that is insufficient for the battery, subject
to a strong discharge current.
The battery will be selected with regard to the greatest value resulting from the calculations set
out above.
The battery capacity determines the adjustment of the configuration {1137} “battery charge
current”. A value between 0.1 and 0.2 x C batt. [Ah] (C10) enables an optimum charge to be
guaranteed.
The method proposed below is strictly indicative and in no way constitutes a guarantee
of perfect dimensioning. The installer is solely responsible for good dimensioning and
installation
4.3.2 DIMENSIONING THE INVERTER
The inverter is dimensioned in such a way that the rated power output covers the power of all the
consumers which will be used at the same time. A dimensioning margin of 20 to 30% is
recommended to guarantee that the Xtender will work well in an ambient temperature of more
than 25 °C.
4.3.3 DIMENSIONING THE GENERATOR
The power output of the generator must be the same or more than the average daily power.
Optimally, it should be two or three times this power. Thanks to the smart boost function it is not
necessary to over-dimension the generator. Indeed, the loads that are temporarily higher than the
power of the generator will be supplied by the inverter. Ideally it should not have a power output
by phase that is less than half of the power of the Xtender(s) present at this phase.
The power available downstream of the inverter when the generator is working is the
same as the sum of the two powers.
4.3.4 DIMENSIONING THE ALTERNATIVE ENERGY SOURCES
In a hybrid system, the alternative energy sources such as the solar generator, wind power and
small hydropower should, in principle, be dimensioned in such a way as to be able to cover the
average daily consumption.
4.4 Wiring diagrams The diagrams shown in the appendix of this document are subsidiary. The applicable local
installation regulations and standards must be adhered to.
The elements referred to with an uppercase letter denote the alternate current (AC) part.
The elements referred to with a lowercase letter denote the direct current (DC) part.