Solar Panel and Battery Sizing Calculator
Sizing an off grid solar system means matching what you use each day to what your panels can generate and what your battery can store. This calculator does both jobs. Enter your daily energy use in watt hours, the peak sun hours your location gets, the system voltage of your battery bank, and how many days of backup you want, and the tool returns the solar array wattage you need and the battery capacity in amp hours. It adds a system loss margin for wiring, charge controller and inverter inefficiency, and it derates the usable battery capacity so you do not discharge lead acid or lithium cells too deeply. This helps you plan a cabin, an RV, a boat or a backup power setup without guesswork. Enter your numbers and read a practical starting specification instantly. Everything runs locally in your browser, so it is private and immediate.
How to use Solar Panel and Battery Sizing Calculator
- Enter your daily energy load in watt hours.
- Enter the average peak sun hours for your location.
- Enter the system voltage and desired days of autonomy.
- Read the recommended solar array wattage and battery bank size.
Frequently asked questions
How does it size the solar array?
It divides your daily energy load by the average peak sun hours to find the panel wattage needed to replace what you use each day.
What do days of autonomy control?
Days of autonomy set how long the battery bank must run without sun, so more autonomy days scale up the required battery capacity.
Why does system voltage matter for the battery bank?
A higher system voltage lowers the amp hours needed for the same energy, so the tool uses your bus voltage to convert watt hours into a battery amp hour target.
What is Solar Panel and Battery Sizing Calculator?
Sizing an off grid solar system means matching what you use each day to what your panels can generate and what your battery can store. This calculator does both jobs.
Is Solar Panel and Battery Sizing Calculator free to use?
Yes. Solar Panel and Battery Sizing Calculator is completely free, with no sign-up and no usage limits.
Does Solar Panel and Battery Sizing Calculator work in a web browser?
Yes. Solar Panel and Battery Sizing Calculator runs in any modern web browser. There is nothing to download or install.
Is my data private with Solar Panel and Battery Sizing Calculator?
Yes. Solar Panel and Battery Sizing Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
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