Home / Runtime calculator
How long will your Pace battery last?
Enter your system and your average consumption: the calculator gives the usable energy, the hours of autonomy and the time the batteries reach your cut-off.
Most racks with a Pace board are 16S 100 Ah units of 5.12 kWh at 51.2 V, so the calculator starts with two of them. Change the number of packs and the capacity if yours are 200 Ah (10.24 kWh).
Pace Monitor does this calculation live, with your real consumption: the dashboard shows when the batteries will be full or reach your cut-off. See it in the demo →
The formula
autonomy = capacity × health × (charge − cut-off) × efficiency ÷ (consumption + inverter’s own consumption)
Example with two 5.12 kWh packs: 10.24 kWh, from 90 % to a 10 % cut-off, behind an inverter at 92 % that uses 35 W for itself, with an average draw of 500 W: 10.24 × 0.8 × 0.92 ÷ 0.535 ≈ 14 hours.
Why real runtime is often shorter
- One weak cell ends the discharge. Your pack is only as long-lasting as its weakest cell: the BMS cuts off when that one reaches its limit. The wider the spread, the earlier the night ends.
- The displayed charge drifts. The state of charge is counted, not measured: without a full charge from time to time, it can be several points off.
- Cold reduces what you can take out. Below about 10 °C a lithium battery delivers less, and many BMS limit the current.
- Peaks cost more than the average. Peaks matter: a 2 kW kettle or pump running a few minutes takes more than the simple average suggests, through losses and current limits.
As a guide: 100 to 250 W through the night, 400 to 1,000 W in the evening for most homes. Within a few days your box measures your own figure.
Keep reading
See what the Pace board inside your rack knows
Order Pace Monitor, shipped on 10 November 2026 and tested on a Pace BMS before it leaves.
Plug & play: working in about a minute