Battery Runtime Calculator – 48V

Q: How long will a 48V 200Ah battery last?

At 80% DoD and 95% efficiency (lithium): 200 × 48 × 0.8 × 0.95 = 7,296 Wh usable. At 500W load: 14.6 hours. At 1,000W: 7.3 hours.

Q: Why is 48V preferred for home solar?

48V is the industry standard for residential solar battery banks. At the same power, 48V draws one-quarter the current of 12V, requiring much thinner cables between battery and inverter. Most quality home inverters (3–10 kW) are designed for 48V input. Popular lithium battery systems (Pylontech, BYD, etc.) are all 48V.

Q: How many solar panels to charge a 48V battery bank?

Rule of thumb: for every 100Ah at 48V (4.8 kWh), you need about 1–1.5 kW of solar panels in a typical climate with 4–5 peak sun hours, assuming you want to recharge within one day. A 200Ah 48V bank (9.6 kWh) needs about 2–3 kW of panels.

48V is the standard for residential solar energy storage — Pylontech, BYD, Victron, and most quality home inverters all operate at 48V. At this voltage, current is just one-quarter of an equivalent 12V system, so cables stay thin even at high power. Enter your battery bank Ah and load to find runtime.

Calculate 48V Battery Runtime

Battery Capacity (Ah)

Battery Voltage (V)

Load (Watts)

Depth of Discharge (%)Lithium: 80–90%. Lead-acid: 50%

System Efficiency (%)

Runtime Results

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Runtime (hours)

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Hours & Minutes

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Usable Energy (Wh)

Formula

Usable Wh = Ah × 48 × (DoD ÷ 100) × (Efficiency ÷ 100)
Runtime (hrs) = Usable Wh ÷ Load Watts

48V Runtime Quick Reference (80% DoD, 95% efficiency – Lithium)

Battery	Usable Wh	200W Load	500W Load	1kW Load
48V 100Ah (4.8 kWh)	3,648 Wh	18.2 hrs	7.3 hrs	3.6 hrs
48V 200Ah (9.6 kWh)	7,296 Wh	36.5 hrs	14.6 hrs	7.3 hrs
48V 300Ah (14.4 kWh)	10,944 Wh	54.7 hrs	21.9 hrs	10.9 hrs

Frequently Asked Questions

How long will a 48V 200Ah battery last?

With lithium at 80% DoD and 95% efficiency: 200 × 48 × 0.8 × 0.95 = 7,296 Wh usable. At 500W average home load: 7,296 ÷ 500 = 14.6 hours — enough for overnight if solar charges it during the day. With lead-acid at 50% DoD: 200 × 48 × 0.5 × 0.9 = 4,320 Wh ÷ 500W = 8.6 hours.

Why is 48V preferred for home solar?

At 48V and 5 kW inverter output: current = 5000 ÷ 48 = 104A DC. At 12V: 417A DC — requiring enormous cables. 48V keeps DC cable currents manageable. All major residential battery systems (Pylontech US5000, BYD Battery-Box, Dyness, etc.) and quality inverter-chargers (Victron, SMA, Growatt, Deye) use 48V. It's the clear standard for 3–10 kW systems.

How many solar panels to charge a 48V battery bank?

Panel kW needed ≈ (Battery kWh × 1.2) ÷ peak_sun_hours. For a 9.6 kWh (200Ah 48V) bank at 4 sun hours: (9.6 × 1.2) ÷ 4 = 2.88 kW of panels. The 1.2 factor accounts for system losses. Size panels generously — extra capacity is rarely wasted as it charges faster on partial days.