Robot Battery Runtime Calculator

Work out robot battery runtime instantly with clear inputs, formula shown and shareable results.

About Robot Battery Runtime Calculator

Runtime is usable energy divided by average power. Average power is the number to get right: a mobile robot spends much of its time idle or stationary, so a duty-cycle-weighted average of drive, lift, compute and idle power gives a far better answer than peak draw.

Formula

Runtime

usable Wh = Ah x V x usable fraction; runtime = usable Wh / average power

Worked example

With the default values below, Robot Battery Runtime Calculator returns Runtime of 2.56. Change any input above and every figure here is recalculated in your browser.

Inputs used

Battery capacity: 40 Ah
Battery voltage: 48 V
Average power draw: 600 W
Usable capacity: 80 %

Results

Runtime: 2.56 h
Runtime: 154 min
Usable energy: 1,536 Wh
Average current: 12.50 A

Step by step

1Values used
2Runtime
3Runtime= 2.56 h
4Runtime= 154 min
5Usable energy= 1,536 Wh
6Average current= 12.50 A

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why not use the full battery capacity?

Deep discharge shortens life and the robot needs reserve to reach the charger. 80% usable is a common design limit for lithium packs.

How do I estimate average power?

Log current during a representative mission. Drive power dominates during motion but idle and compute loads dominate over a whole shift.