A 13.5 kWh battery does not give you 13.5 kWh. Depth-of-discharge limits and round-trip losses mean what reaches your home is less — see how much.
Battery Energy StorageLive
capacity, efficiency & backup
Controls
Presets
A battery's rated capacity is not all usable: depth-of-discharge limits protect its life, and round-trip efficiency means some energy is lost charging and discharging. What actually reaches your home is capacity × depth-of-discharge × round-trip efficiency. Together with cycle life, these set backup duration and the cost per stored kilowatt-hour.
Reading this result: Usable energy is capacity × depth-of-discharge × round-trip efficiency, so only 10.9 of 13.5 kWh (81%) reaches your home each cycle — the discharge limit removes more here than efficiency does.
Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.
★ Sign in to save this setupSave your tuned setup, or drop this simulation into your own site, docs, or course page.
How it works
Usable storage is the rated capacity times the allowed depth of discharge times the round-trip efficiency, since energy is lost both charging and discharging and reserves protect battery life. Combined with cycle life, these numbers set how long a battery backs up your home and the effective cost per stored kilowatt-hour — the economics of home and grid storage.
✦
Ask the AI about this model
The math, the assumptions, real-world uses, or a code translation — explained for this exact simulation.
Is this battery storage capacity calculator tool really free?▾
Yes. Battery Energy Storage runs entirely in your browser using your device's own compute, so local use is free forever. You only pay Compute Tokens if you scale a job to the cloud.
Do I need to install anything?▾
No. Everything runs client-side in a modern browser — no downloads, no license, no account required to start.
Can I save or share my simulation?▾
Create a free account to save projects, and use a shareable embed or minted DOI to publish a live, interactive version anywhere.
How accurate are the results?▾
The solver uses established numerical methods, but results are for research and educational purposes and should be validated against experiment or professional review before you rely on them.