1. Rentability and annual electricity production of a grid connected PV system

PV system power (in kWp) kWp
Cost of PV system
PV system losses * %
Annual solar exposure ** kWh/m2
Feed-in tariff per kWh
Annual PV electricity output
Annual feed-in income for electricity generated
Return on investment in PV system after
Month electricity prod. in % kWh Income per month
January
February
March
April
May
June
July
August
September
October
November
December
In total:

* losses in PV On-Grid systems amount to 15% (inverter, cable, temp. coefficient - performance ratio)
** in Central and North Europe between 1200-850 kWh/m2 in South Europe up to 2000 kWh/m2.
For details see European Solar Irradiation Table.

All financial data please define in the same currency, for every occurrence (system costs and feed-in tariff).


Kalkulatory

2. Knowing the PV power (Wp) which battery capacity (Ah) ?

PV System power (solar generator) Wp
PV system losses * %
Daily solar exposure ** h
System voltage V
Permissible battery discharge level *** %
Daily power generated
Daily current generated
Required battery capacity
Days with no current consumption (amount of charging cycles) days
Battery capacity for a several-day-long cycle

* loses in PV Off-grid systems amount 20-25% (cable, charge controller, battery system)
** average daily solar exposure 5-6h (eg. summer 8h, winter 4h), depending on european location
*** in order to protect battery and avoid deep discharges (ref. 50% discharging considered as safe)

To optimize the system capacity:

1. Define whether the system will work: all year, only in summer or spring-summer-fall mode ? Please use the daily solar exposure (in hours) to define the working mode. Eg. for summer 8 hours or for all-year-system (incl. winter) 4 hours.
2. Major influences on optimal system design are: quality, technology, storage temperature and system-voltage.


Kalkulatory

3. Knowing the battery capacity (Ah) which PV power (Wp) ?

Battery(s) capacity Ah
PV system losses * %
Daily solar exposure ** h
System voltage V
Premissible battery discharge level *** %
Required PV power - for one day cycle (whole year average)
Days with no current consumption (amount of charging cycles) days
Required PV power - for several-day-long cycle

* loses in PV Off-grid systems amount 20-25% (cable, charge controller, battery system)
** average daily solar exposure 5-6h (eg. summer 8h, winter 4h), depending on european location
*** in order to protect battery and avoid deep discharges (ref. 50% discharging considered as safe)

To optimize the system capacity:

1. Define whether the system will work: all year, only in summer or spring-summer-fall mode ? Please use the daily solar exposure (in hours) to define the working mode. Eg. for summer 8 hours or for all-year-system (incl. winter) 4 hours.
2. Major influences on optimal system design are: quality, technology, storage temperature and system-voltage.


Kalkulatory

4. Knowing the current demand (Wh) which PV power and battery capacity (Wp, Ah) ?

Appliances power demand W
Appliances running time h
PV system losses * %
Daily solar exposure ** h
System voltage V
Premissible battery discharge level *** %
Daily energy demand
Monthly energy demand
Required battery capacity
Required PV system power

* loses in PV Off-grid systems amount 20-25% (cable, charge controller, battery system)
** average daily solar exposure 5-6h (eg. summer 8h, winter 4h), depending on european location
*** in order to protect battery and avoid deep discharges (ref. 50% discharging considered as safe)

To optimize the system capacity:

1. Define whether the system will work: all year, only in summer or spring-summer-fall mode ? Please use the daily solar exposure (in hours) to define the working mode. Eg. for summer 8 hours or for all-year-system (incl. winter) 4 hours.
2. Major influences on optimal system design are: quality, technology, storage temperature and system-voltage.