Technical data

ManualsBrandsAeca ManualsBattery ChargerXTH 3000-12

General recommendations

Inverter Selection

Inverter selection

(V)

100 500 1,000 2,000 5,000 10,000

Steca AJ Steca Solarix PI

Inverters

1,000 2,000 3,000 5,000 (W AC)

Steca

Compact

Steca

HPC

Steca

XPC

100,00010,000 20,000 50,000

Inverters with battery chargers

(V)

Steca

Xtender XTM

Steca

Xtender XTH

(W AC)

22|

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a high overload capacity, particularly in the start-up

phase. The battery must also possess a large enough

capacity so that sufficient currents are made availa-

ble to the inverter in the start-up phase. We recom-

mend choosing the battery size according to the fol-

lowing formula: the battery capacity should be at

least five times as large as the rated power of the

inverter divided by the rated voltage of the battery.

batt

≥ 5 h * P

nom

/ U

nom

is the rated power of the inverter in watts and

nom

is the rated voltage of the battery.

Selecting the system voltage

The power requirement of the loads should be the

decisive factor when choosing the system voltage.

The higher the power, the higher the system voltage.

If no 12 V DC loads are connected to the system,

a higher system voltage of 24 V or 48 V should be

chosen in order to reduce the alternating currents,

and thus the losses on the DC side. Inverters also

generally work more effectively with a higher input

voltage. All in all, a higher system voltage leads to

the system having a greater efficiency, since losses

are reduced

Cable lengths and cross sections

Direct currents in inverter systems are typically lar-

ge. For this reason, it is important to dimension

the cables between the battery and the inverter ap-

propriately. Always connect the inverter directly to

the battery. The cable you use should be as short

as possible. In addition, the cable cross section

should match the expected flow of current. In case

of doubt, a thicker cable should be chosen. This can

have a significant influence on the overall behaviour

of the system. Using thick and short cables can limit

losses and thus allow you to create a system with a

better level of efficiency and/or better performance.

If the cables on the direct current side of the inver-

ter are included in the delivery, these should not be

lengthened, and a smaller cross section should not

be used.

General recommendations

for alternating current and hybrid systems.

Sine wave inverters

In contrast to so-called square wave or trapezoidal

inverters (grey square curve), Steca sine wave inver-

ters produce a real and precisely controlled sinus

wave (red sinus wave) at their output. The sinus

wave inverters assure that all loads which are sui-

table for grid operation can also be operated on a

solar home system without any problems. Further-

more, they offer the advantage that no significant

noises are produced in the inverter and there is no

loud background noise to be heard on a connected

radio, for example.

Selecting an inverter

The power of the inverter must be selected according

to the way it will be used. The sum of the power of

all loads must not exceed the rated power of the in-

verter. The maximum power of the inverter must be

able to cover the starting currents of the loads.

In order to allow the connection of more loads, Steca

recommends overdimensioning the inverter.

Selecting the PV generator and solar charge

controller

The solar module array has to be adjusted to the local

sunlight conditions and the system‘s energy require-

ment. In order to avoid stagnation times, the PV gene-

rator must also provide enough power during months

with little solar radiation in order to cover the require-

ment of the connected loads.

The chosen solar charge controller must also be sui-

table for the maximum short-circuit current of the PV

generator and the maximum load current. In some ap-

plications, however, technical properties also play an

important role in the choice of solar charge controller.

This may mean that a high-performance solar charge

controller with corresponding additional functions is

used in a system with a low output.

In order to keep the initial investment small, we recom-

mend planning the size of the PV generator and bat-

tery according to the current energy consumption and

choosing a solar charge controller which will allow the

system to be expanded later.

Selecting the battery

In order to also be able to supply loads with high

requirements without any problems, the size of the

battery must be chosen with care. Some critical loa-

ds such as fridges, freezers, pumps and motors need

extremely high starting currents in their start-up

phases. In order to be able to power such loads, it

is important to use a high-performance inverter with

nom

inverter U

nom

battery Battery capacity

200 W 12 V > 100 Ah

500 W 12 V > 200 Ah

1,000 W 12 V > 400 Ah

2,000 W 12 V > 800 Ah

2,000 W 24 V > 400 Ah

3,500 W 24 V > 700 Ah

3,500 W 48 V > 350 Ah

5,000 W 48 V > 500 Ah

7,000 W 48 V > 700 Ah

Sine wave

Square wave