Will your battery last the weekend?

Start with energy, then check when you use it and when you can recharge.

1. Use energy over a day, not just the label watts

Battery capacity is normally given in watt-hours (Wh). A device drawing 25 watts continuously uses 600 Wh over 24 hours: 25 × 24. A compressor fridge switches on and off, so its label power is not necessarily its average draw. Prefer measured Wh/day for your actual equipment and conditions.

2. Keep capacity and losses separate

The planner starts with rated battery capacity, applies your usable-capacity percentage, and then applies the starting-charge percentage. Device energy is divided by the output efficiency you enter. If your measurements already include those losses, use 100% for the corresponding factor so the same loss is not counted twice.

Planning reserve is a margin you choose. It is separate from the battery's physical protective cutoff.

3. Check the overnight low point

Enough solar energy over a whole trip does not guarantee continuous power. The battery may empty before the next charging window starts.

4. Compare weaker charging assumptions

The three curves use your entered charging input, a quarter of that input and no solar. These are sensitivity checks, not predictions of sunshine. Enter the power actually reaching the battery, rather than assuming a panel continuously delivers its rated output.

Before you buy a power station

Use the result to check your requirements before comparing products. This independent calculator does not choose a brand or certify that a particular model will run your equipment.

1. Check the weakest charging case. Try the no-solar scenario. If the battery runs short, reduce the load or compare a larger capacity with the same assumptions. Extra solar cannot fix an interruption that happens before charging starts.
2. Check available energy, not just the advertised Wh. Re-enter the capacity and usable-capacity assumptions for the model you are considering. Output losses and always-on inverter draw can change the result. Prefer measured consumption over generic appliance examples.
3. Check the hardware separately. Verify output voltage, continuous and surge power, port limits, and solar input compatibility in the exact model's manual. Enough Wh does not establish that a port can power a device.
4. Check the right storefront. Regional versions, sockets, warranty and delivery can differ. Confirm the model and terms for your country before ordering.

We have not hands-on tested or ranked products. Manufacturer information links below are ordinary references. The optional Jackery store link is an affiliate link and does not change the calculator's estimates.

What the planner cannot determine

This is an energy-planning estimate. It does not check power-port limits, starting surges, charging compatibility, BMS restart behavior, temperature effects, battery health or safe food storage. Daily fridge use is averaged across 24 hours. The calendar uses fixed 24-hour campsite days and does not model daylight-saving changes.

Check your equipment's specifications and actual consumption separately. This tool is not intended to determine medical-power sufficiency or design electrical installations.

Sources for the underlying quantities

Jackery: device energy and runtime estimates · EcoFlow: solar conditions. These references do not calibrate or endorse this independent calculator.