Technical data

PV
OFF GRID
46|46|
|47
Steca Elektronik GmbH | 87700 Memmingen | Germany | Fon [phone] | Fax [phone] | www.stecasolar.com
Single-phase
hybrid system concept
The central, intelligent element within the system
is the Steca Tarom or Power Tarom solar charge
controller. The energy flow is controlled by this
device, and the battery is protected from critical
states. The Tarom/Power Tarom is directly con-
nected to the battery.
Also connected to the battery is the DC bus.
Using a shunt, the Steca PA HS200, which is situ-
ated on the minus cable attached to the battery,
the battery current is measured and this informa-
tion is passed on to the Tarom/Power Tarom. Fur-
ther components, such as an inverter or the Steca
PA 15 remote control, are directly connected to
the DC bus. In order to automatically start a die-
sel generator if the battery’s state of charge (SOC)
falls below an adjustable threshold, the output of
the PA 15 is connected to a relay. In turn, the
normally open contact of the relay switches the
diesel generator on, and subsequently switches
it off again.
The Tarom/Power Tarom controls the DC hybrid
system. The PA HS200 current sensor transfers
all information on the charge and discharge cur-
rents at the DC bus to the Tarom/Power Tarom.
With the aid of this data, the controller is able to
calculate the current charge status of the battery.
This information is transferred via the DC cabling
(powerline modulation) to all connected Steca PA 15s.
Every PA 15 can be independently configured to a
certain switch-on and switch-off threshold of the
charge status.
If, in the above example, the inverter is discharging
the battery, then this information is transferred to the
Tarom/Power Tarom, which calculates the charge sta-
tus. As soon as the charge status falls below the ap-
pointed threshold value of the connected PA 15 (e.g.
30 %), the controller switches on the diesel generator
via a relay. The load is now being supplied from the
generator, and at the same time the battery is being
recharged. After the charge status has reached the
PA 15’s appointed upper value (e.g. 90 %), the diesel
generator is switched off again.
In order to create an automatic energy management
system, the AC output of the diesel generator is con-
nected to the AC input of the inverter with integrated
battery charger. The load is always connected to the
output of the inverter. If the diesel generator is running,
and this current flows to the inverter, then the inverter
automatically switches to transfer mode. The loads are
supplied from the diesel generator whilst the battery
recharges via the inverter. If the AC output voltage of
the diesel generator falls under a certain voltage level,
which can be adjusted on the inverter, then battery
operation is automatically switched back on.
This system allows automatic energy management
which gets optimum use from the available solar
energy, maintains the batteries reliably, and ensures
electricity supply around the clock.
Important features
Combination of different power sources like PV,
wind, diesel generators, etc.
24 h / d full 230 V~ power supply
12 V / 24 V or 48 V overall DC-bus
Automatic energy management regulation based
on the State of Charge of the battery. Including
automatic start of controllable power sources like
e. g. diesel generators
Optimised battery charging algorithm
Data logger function with automatic alarm






Hybrid Systems
The main feature of a hybrid system is the
use of two or more different electricity
sources.
Among solar energy, photovoltaic hybrid systems
generally employ a diesel generator, a wind turbi-
ne or the public grid as a further electricity sour-
ce. The inverters used in hybrid systems, which
have integrated battery chargers, supply the
connected AC appliances according to demand
from the battery bank, solar energy or the se-
cond electricity source. These devices also allow
the batteries to be recharged from the extra en-
ergy source.
Photovoltaic hybrid systems offer the advantage
that the solar generator does not have to be si-
gnificantly oversized for periods of low sunlight.
This avoids substantial costs. When selecting its
energy source, the system always gives priority to
the energy provided by the module. In combina-
tion with a controllable second source, the ener-
gy supply remains reliable and available 24 hours
a day, all year round.
The proper inverters for single-
phase Steca hybrid systems are
inverters with integrated battery
charger:
– Steca XPC,
– Steca Compact,
– Steca HPC and
– Steca Xtender.
Possible connected loads are from
1.4 kW at 12 V up to 24 kW at
48 V.
Generator
Solar charge
controller
Steca
Power Tarom
Steca
PA Tarcom
Battery Battery Battery Battery
Inverter
Steca HPC
230 V
Steca
PA 15
Steca
PA HS200
Grid
Wind
Steca
PA 15
Inverter
Steca HPC
Diesel
generator