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🔋 Battery Bank Sizing Calculator

Size an RV, marine, or solar battery bank from your total daily amp-hour load. The result shows the recommended bank Ah and a 12V or 24V series-parallel configuration using Chengguang batteries.

Formula: Bank Ah = (Daily Ah × Autonomy Days) ÷ Max Depth of Discharge

Load & System Parameters

If you know watts, divide total watt-hours by system voltage.

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:material-help-circle: Frequently Asked Questions

What is a battery bank?

A battery bank is a group of batteries wired in series and/or parallel to provide the required system voltage and amp-hour capacity. Series raises voltage, while parallel raises capacity.

How do I convert daily watt-hours to amp-hours?

Divide total daily watt-hours by the system voltage. For example, 1,200Wh per day on a 12V system is about 100Ah per day.

Why add days of autonomy?

Autonomy covers periods without sufficient charging, such as cloudy days for solar systems or days without shore power. Two days is a common buffer for off-grid use.

What depth of discharge should I use?

Use 30-50% for flooded and deep-cycle batteries to maximize service life, or up to 80% for AGM batteries. Shallower cycling generally extends battery life.

Does this replace a professional design review?

No. This is a sizing estimate, not a substitute for professional review of cable sizing, fusing, ventilation, charging, and local electrical codes.