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Van Battery Sizing

The battery bank is usually the most expensive part of a van build, and the easiest one to get wrong. These pages size it from your actual daily watt-hours. To size a whole system at once, use the calculator.

How this site sizes a battery bank

Every battery page uses the same arithmetic: daily watt-hours × days of autonomy ÷ depth of discharge, where depth of discharge is 0.8 for LiFePO4 and 0.5 for AGM. Cold weather adds a further 0.8 derate, because a lithium bank you cannot charge below freezing is effectively a smaller bank. The full method is written out on the about page, and the wiring and fuse side is covered under components.