Solar System Calculator
Size your solar panel array, battery bank, and inverter based on your energy needs and location.
New to off-grid? Start with our 3-question path finder for a personalized off-grid guide.
Calculation Assumptions
- 75% overall system efficiency (wiring, temperature derating, charge controller, battery round-trip)
- LiFePO4: 80% depth of discharge · Lead-acid: 50% depth of discharge
- 20% battery safety margin for capacity headroom
- Prices in EUR as of 2026-07-13. EUR placeholder prices — verify against Irish installer/SEAI retail quotes before production use.
- Inverter sized at 1.25× peak load; MPPT controller sized at 1.25× array watts ÷ system voltage
System Summary
Updates live as you adjust inputs.
Solar Array
1,200
W
Panels
3
× 400W
Battery
250
Ah @ 24V
Inverter
1,500
W
Solar Array
3 panels
400W × 3 = 1,200 W total
Min required: 953 W (at 2.8 peak sun hrs)
Battery Bank
6,000 Wh
250 Ah at 24V · LiFePO4
2 days autonomy · 20% safety margin
Inverter & Charge Controller
Inverter
1,500 W
pure sine wave
MPPT Controller
80 A
charge controller
Estimated Cost
Estimates based on EUR placeholder prices — verify against Irish installer/SEAI retail quotes before production use. Prices as of 2026-07-13. Does not include installation labor or permitting.