Wall-mounted lithium battery cabinets in an off-grid utility shed with copper bus bars

Battery autonomy calculator

How many days will your batteries keep the cabin running if the sun never shines? Plug in your bank size and your daily power use — get days of runtime back.

Result

Days of autonomy
Usable energy

What the result means. "Days of autonomy" tells you how long your bank can carry the daily load before it hits the depth-of-discharge cutoff. Below that, you risk damage to the cells, so the calculator stops there even though there's still juice in the battery.

Reality check. Real-world batteries lose capacity in cold weather (LiFePO4 won't charge below freezing without an internal heater). Build in a 10-15% buffer if your bank lives in an unconditioned shed.

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