Robot Battery Life at Events: Planning the Charging

The manufacturer figures we could check put battery life at around two hours for a humanoid such as the Unitree G1 – well short of a full event day. A long event therefore needs a plan: spare batteries, scheduled charging breaks or a second robot. Published figures are only a starting point, because real runtime depends on the robot's configuration and what it is asked to do.

What manufacturers publish

The figures below come from manufacturer pages and documentation. They describe the battery, not your event.

Unitree G1 (humanoid, about 1.3 m): a 9,000 mAh quick-release smart battery, battery life of about two hours, and a 54 V, 5 A charger. Unitree adds that its parameters vary with scenario and configuration. See Unitree G1.
Unitree H1 (full-size humanoid): an 864 Wh battery that Unitree describes as quickly replaceable. The product page gives no runtime. See Unitree H1.
Unitree Go2 (robot dog): a standard 8,000 mAh battery for about 1–2 hours; the EDU version lists a 15,000 mAh long-endurance battery for about 2–4 hours and a fast charger. See Unitree Go2.
Pepper (wheeled humanoid): a lithium-ion battery rated at 30 Ah and 795 Wh. Pepper can be used while plugged in, but the battery charges only when the robot is switched off and connected to its adapter. See Pepper.
NAO V6 (small humanoid): a 62.5 Wh battery with a charging time of 90 minutes. As with Pepper, NAO can run on its adapter, but the battery only charges while the robot is off. See NAO.

The Aldebaran documentation pages consulted for Pepper and NAO list capacity and charging details but no runtime, so ask the supplier how long their units last in a programme like yours.

Why event runtime differs from the spec

Runtime figures are measured under particular conditions, and Unitree notes that its parameters vary by scenario and configuration. Ask the supplier how their figure was measured and how your programme compares: continuous walking among visitors, a dance every half hour, or mostly standing and greeting.

Heat and logistics matter too. Aldebaran notes that if Pepper's battery is already hot – for example after dancing for a long time – charging may wait until it has cooled. The G1 manual from Unitree's German distributor says a warm battery should cool to room temperature before charging, that only official chargers should be used, and that a battery may arrive with little or no charge because of self-discharge during transport and storage. Build that into the setup day: charge on arrival, not just before the doors open.

Three ways to cover a long day

1. Battery swaps

Quick-release batteries make swaps possible, but they are not instant. For the G1, the distributor manual describes shutting the robot down in a sitting or suspended position to avoid sudden falls, and a boot process of about a minute after powering on before the robot can be brought back into operation. Plan each swap as a short off-stage break, out of visitors' reach. Swapping is a normal way to cover long distances: the Beijing humanoid half marathon allowed teams to replace batteries during the race.

2. Charging breaks

For robots that only charge when switched off, such as Pepper and NAO, charging means the robot is out of action. NAO's documented charging time is 90 minutes. Fit charging into natural breaks in the programme – lunch, keynotes, quiet hours.

3. A second robot, or a rotation

For long opening hours with few breaks, two units rotating between the stand and the charging point can be simpler than squeezing swaps into a busy schedule. It costs more, so compare it with spare batteries when you look at quotes (see comparing robot hire quotes).

Building the schedule

A rough method, to be checked with the supplier:

List the hours the robot should be visible, and mark which are active (walking, dancing) and which are calm (standing, talking).
Ask the supplier for a realistic runtime per battery for that mix.
Divide the active day by that runtime to estimate how many battery cycles you need.
Compare that with the number of batteries and chargers the supplier brings, and with the charging time per battery.
Put every swap or charge into the run-of-show, with a time and a place.

As an illustration only: if a robot runs for about two hours per battery and the stand is open for eight hours, that is roughly four battery cycles, so the supplier needs either several charged batteries or enough time to recharge between slots. If charging a battery takes longer than the robot runs on one, a two-battery rotation will not keep up, and you need more batteries or longer breaks.

Power and the charging point

humanoid4rent's safety page suggests confirming how many sockets you have, on which circuit, and whether charging happens on the stand or backstage. A secure backstage charging point keeps chargers and warm batteries away from visitors. According to the distributor manual, the G1 charger takes 100–240 V AC. If a robot uses a charging station, follow the manufacturer's warnings; Aldebaran advises not to move the station while Pepper docks and not to stand in its way when it leaves. Do not forget the controllers: the G1's remote has its own battery, with a stated running time of five hours.

The venue checklist covers power and access questions in more detail.

Battery checklist

Realistic runtime per battery for your programme, confirmed by the supplier.
Number of batteries and chargers, and charging time per battery, confirmed.
Charging location agreed: sockets, circuit, security, away from visitors.
Swaps and charging breaks written into the run-of-show.
Batteries charged on arrival, not just before opening.
Controllers and any tablets charged.
Backup plan if a battery or charger fails (see what happens if the robot fails).
For multi-day events: overnight charging location and security agreed.

When you send a request, give the opening hours and the active segments so suppliers can quote the right number of batteries or units.

FAQ

How long does a humanoid robot battery last?

It depends on the robot and the activity. Unitree lists about two hours for the G1; for other models, ask the supplier for a runtime that reflects your programme rather than a catalogue figure.

Can a robot run while it is plugged in?

Some can. Aldebaran's documentation says Pepper and NAO can be used while connected to their adapters, but their batteries only charge when the robot is switched off.

How long does charging take?

NAO's documentation gives 90 minutes. The Unitree G1 sources consulted do not state a charging time, so ask the supplier how long each battery takes on their chargers.

Do we need a second robot for a full-day event?

Not necessarily. Spare batteries and scheduled breaks can cover a long day if the numbers work; a second unit makes sense when the robot must be visible almost continuously.

Sources

How this guide was made: prepared with AI assistance; every factual statement was checked against the sources listed above on 12 October 2026. Spotted an error? Write to info@humanoid4rent.com.