Floor Zones for Two Robots: Splitting Traffic and Charge Time

What decides whether both robots finish

Two floor robots finish a night when three things hold. Each zone is sized to the time its machine actually needs, the boundary between the two zones is drawn on purpose, and charging never leaves a unit parked mid route. Miss one of them and the morning crew finds a partly cleaned corridor, a robot waiting on a charger, or two machines working the same aisle.

Splitting by square footage alone is the most common mistake. A 30,000 square foot back office and a 30,000 square foot lobby can need very different run times, because the lobby takes foot traffic, grit and spills all day.

How to size each zone by traffic and square footage

Start with a floor plan and measure each zone in square feet. Then weight it. Entries, food service paths and high traffic corridors soil faster and often need a second pass, so they carry more weight than quiet storage aisles.

Next, convert area into time. Vendor rates are ceilings, not promises. The CenoBots model listed through Americhem shows cleaning efficiency up to 20,000 square feet per hour, and the real rate depends on brush mode, aisle width, turns and obstacles. Time a test pass on your own floor and use that measured rate.

Illustrative numbers only: suppose a lobby and corridor zone totals 40,000 square feet, the measured rate is 10,000 square feet per hour, and the zone needs two passes. That zone alone is eight hours of run time for one robot, which may be more than the night allows. The split then has to move area or traffic weight to the second unit, or the plan needs a shorter pass rule.

Drawing the boundary so neither robot doubles back

The boundary is where most double work hides. A line drawn through the middle of an open aisle sends both units into the same clutter. Put it on a physical break and leave a short overlap, so no strip goes uncleaned.

A good boundary is written down before the first run, with the map version and date. A boundary that exists only in someone's head tends to drift within a few weeks.

• Cut at a fire door, a wall break or a change from carpet to hard floor, not at an arbitrary grid line.
• Assign any shared aisle to one robot only, and record which one in the site map.
• Keep the handoff point off the route to either charger, so a returning unit never crosses the other's path.

Why charge time sets the split

Charge time is the number most often left out of a zone plan, and it can outweigh the square footage math. Vendor listings show a wide spread. The Kärcher KIRA BR 200 spec lists 4.5 hours of runtime and 5.3 hours of battery charging time. The Naviarobotics Scrubber 85 lists a 3 hour charge. The Pudu CC1 listing shows 5 hours of sweeping or vacuuming and a 3 hour charge, though runtime shifts with mode. The CenoBots model shows 2.5 hours of runtime and a 2.2 hour charge. Nilfisk's SC50 page says runtime is up to 10 hours and can be extended with battery modules. The Universal Robotics Scrubber 50 listing claims up to 4 hours on a single charge, with no charging time given.

These are vendor-reported figures from listings checked in November 2026. The listings do not always state test conditions, so treat them as starting points and get charge time in writing from the vendor before you plan around it.

Here is the arithmetic with the Kärcher figures. A unit started at the beginning of an eight hour window runs until 4.5 hours, then charges until about 9.8 hours. Its second run cannot begin inside the window at all. For that unit, one full run is the night, and the other robot must carry the rest.

Closing the idle charging gap

An idle gap happens when a robot finishes early and waits, or when it returns to a charger another unit is already using. Both are avoidable with timing and placement.

Stagger the starts so one unit works its first block while the other charges, then swap roles at the midpoint. Place the chargers far enough apart that a returning robot never queues behind its partner. Ask whether the model supports a second battery set or a battery swap. The Kärcher listing describes four batteries in its configuration, but confirm what the model you quote actually supports.

Also ask how the robot resumes after a charge. A resume that restarts a zone from the beginning wastes the window you planned to save.

Reading the morning log to confirm both finished

The log is the proof. Before the first full week, check four things: each zone's start and stop times against the plan, charge start and end times for each unit, idle minutes between a finished zone and the next run, and any zone marked skipped or partly covered.

A zone that runs long every night needs a bigger share or a pass rule change. A zone that never reaches its planned end time usually points to a boundary or map problem, not a crew problem. Record the map version in each log so every night's result matches the layout it ran on.

Where Service Robot Co. fits in the plan

Service Robot Co. is a full service commercial robot integrator for US businesses, and we do not favor one manufacturer. We select the models that fit each site's floor, traffic and night window, then offer them on lease through financing. The zone split, charger placement and boundary rules are set during a site assessment, and the fixed lease payment is quoted after that assessment.

Each unit is deployed, trained and serviced under RoboCare, our service plan, backed by regional service engineers in every state we service. The people who draw the zones can review the first morning logs with you, so adjustments can happen early rather than after weeks of missed corridors.