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Off-Grid Solar & Battery Storage Sizing Calculator

Size off-grid solar storage, telecom base stations and microgrids: calculate required battery bank Ah/kWh, PV array peak wattage (Wp), module string count and MPPT charge controller current based on daily kWh, autonomy days, DOD and peak sun hours.

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How to use Off-Grid Solar& Battery Storage Sizing Calculator

  1. Enter Daily energy consumption (kWh/day) and adjust the options as needed.
  2. Run the tool and inspect its results, evidence and limitations.
  3. Copy or download the result, then verify it against the actual website, source data or business records.

Try a concrete example

For a 15 kWh/day load at 48V DC with 2 days autonomy, using LiFePO4 (85% DOD) requires a 36.8 kWh battery bank (48V 766 Ah). In a 4.5 PSH region with 20% system loss, a 4167 Wp PV array is required (eight 550Wp panels), paired with an 80A to 100A MPPT charge controller.

How to interpret results

Off-grid renewable sizing follows energy conservation and daily energy balance. Daytime solar generation must meet real-time daytime loads while fully recharging batteries for nighttime and cloudy days. LiFePO4 delivers superior DOD, cycle life and lowest levelized storage cost.

Frequently asked questions

What are Peak Sun Hours (PSH)?

PSH converts variable daily solar insolation into equivalent hours of standard test condition sunlight (1000 W/m²). Sunny desert regions reach 5.5~6.5 PSH, while cloudy temperate regions average 3.0~4.0 PSH.

What are the advantages of LiFePO4 over lead-acid batteries?

Lead-acid batteries allow only 50% depth of discharge with 300~500 cycles before degradation. LiFePO4 supports 85%~90% DOD, delivers >95% round-trip efficiency, exceeds 4000~6000 cycles (10-15 years), and cuts bank weight and volume by over 65%.

Why must off-grid sizing include a 15% to 25% balance-of-system loss factor?

Real installations incur dust soiling, temperature derating (~0.4%/°C above 25°C), inverter DC-AC conversion losses (90%~94% efficiency), MPPT tracking loss and cable drop. A 20% margin ensures reliable autonomy during sub-optimal days.

How to size an MPPT solar charge controller?

Controller charging current equals PV array wattage divided by battery charging voltage, plus a 20%~25% cold-weather irradiance margin. A 4167 Wp array charging a 48V bank (~54V absorption) draws ~77.2A, requiring an 80A or 100A MPPT unit.

off-grid solar array and battery storage sizing calculator practical guide and common questions

What does an off-grid solar array and battery storage sizing calculator do?

Off-grid solar design centers on energy balance equations: daily photovoltaic generation must power active daytime loads while recharging battery reserves for night usage and cloudy autonomy days.

Who is this for, and when is it useful?

Renewable energy export managers, off-grid microgrid engineers and solar system integrators sizing solar panels and battery storage banks.

How do I use this off-grid solar array and battery storage sizing calculator?

Enter daily energy consumption, DC bus voltage (12V/24V/48V), autonomy backup days, battery chemistry (LiFePO4 vs Lead-Acid) and peak sun hours (PSH) to calculate battery capacity in Ah and kWh, required PV array Wp, solar module series-parallel count, and recommended MPPT charge controller sizing.

How should I interpret the results?

Lithium Iron Phosphate (LiFePO4) offers 80% to 90% depth of discharge with 95% round-trip efficiency, reducing battery mass and volume by over 60% compared to traditional lead-acid (50% DOD). Sizing accounts for inverter losses, temperature derating and wiring resistance.

Where is the work performed, and which services receive data?

Daily load wattage, battery storage banks and solar array sizing calculate locally in your browser. Customer load profiles are never submitted to any remote server.