SUNMAX 22 Cordless Walk-Behind Floor Scrubber — Battery, Dual Tanks, 31-Inch Squeegee

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What the SUNMAX 22 Cordless Walk-Behind Floor Scrubber Is

It is a battery-powered walk-behind auto-scrubber that cleans hard floors in a single pass: it lays down cleaning solution, scrubs with a 22-inch brush at 50 pounds of pressure, and vacuums the dirty water straight back up through a 31-inch rear squeegee — so the floor is clean and walk-dry right behind the machine. It runs on 24V lead-acid batteries for up to about 5 hours, carries dual tanks (13.2-gallon solution, 14.5-gallon recovery), and weighs around 400 pounds. That combination is built for large open hard floors — tile, sealed concrete, epoxy and VCT.

The heart of it is the one-pass, walk-dry result, which is what separates an auto-scrubber from a mop and bucket: the scrubber removes the soil and the water together instead of leaving the floor wet. It is for hard floors, not carpet — carpet needs an extractor. Being cordless removes cord-in-water hassle and outlet hunting. Compare sizes with the compact 14-inch and corded 22-inch scrubbers, and see our floor-scrubber guide.

One Pass, Walk-Dry: Why It Beats the Mop-Bucket Cycle

The reason an auto-scrubber exists is the one-pass, walk-dry workflow. A mop-bucket cycle is really several jobs: mop the floor, watch it stay wet, cordon it off, and wait for it to air-dry — during which the same bucket water grows dirtier and the wet floor is a slip hazard. This machine collapses that into a single pass: solution down, brush scrubbing, and the 31-inch squeegee lifting the dirty water back into the recovery tank immediately, so the floor behind you is dry enough to walk on. As the review of this class puts it, it shrinks the wet-floor window to the machine's shadow.

That is a productivity story and a safety one. Removing the soil and the water together means a genuinely cleaner floor than a mop that pushes dirt around, and the walk-dry result means far less time with a wet, slippery floor closed off. The honest boundaries stay the same, though: it earns its keep on large open hard floors, not small cluttered ones where a mop bucket still wins; it is for hard floors, not carpet; and you still deploy wet floor signs around the area you are actively scrubbing. Pair it with the right floor chemistry and our wet-floor-sign guide.

Pros & Cons

Specifications

Related Guides

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Frequently Asked Questions

What does an auto-scrubber do differently from a mop and bucket?

In one pass it lays down solution, scrubs the floor with a powered brush, and immediately vacuums the dirty water back up through a rear squeegee — so the floor is clean and walk-dry right behind the machine. A mop and bucket, by contrast, spreads solution, pushes dirt around, and leaves the floor wet to air-dry, often with the same water getting dirtier as you go. The scrubber removes the soil and the water together, which is faster and cleaner on large hard floors.

Why is it cordless, and what is the trade-off?

Battery power means no cord to trip over, drag around furniture, or keep out of the water you are laying down, and no hunting for outlets across a big floor — you just drive it. This SUNMAX runs up to about five hours on a charge. The trade-offs are honest: it is a heavy machine, the batteries are a service item that will need replacing after a few years, and you have to keep them charged and maintained. For large open floors, the freedom of no cord usually outweighs that.

Is it lead-acid or lithium?

This model uses 24-volt lead-acid batteries, not lithium — the lithium version is a separate, more expensive SUNMAX model. Lead-acid is proven and economical, but it is heavier and needs correct charging: charge it in a well-ventilated area, since lead-acid batteries can off-gas hydrogen while charging, and keep the terminals clean. Plan for battery replacement as a maintenance cost over the machine's life, and follow the manual's charging routine to get full battery life.

Why is the 31-inch squeegee wider than the 22-inch scrub path?

On purpose. The scrub brush cleans a 22-inch path, but the recovery squeegee is 31 inches wide so it overhangs the scrubbed area and still catches the water when you turn or track slightly off-line. If the squeegee were only as wide as the brush, tight turns would leave a wet edge behind. The wider squeegee is what actually delivers the walk-dry result across the whole cleaned area, not just the straight-ahead stripe.

What are the tank capacities?

It carries dual tanks: a 13.2-gallon solution tank and a 14.5-gallon recovery tank. The large solution tank means long runs between refills on a big floor, and the recovery tank is slightly larger because it collects the solution you put down plus the soil and any residual water. Empty and rinse the recovery tank after use so it does not sour, and refill the solution tank with correctly diluted cleaner for the next run.

What floors is it for?

Hard floors — tile, sealed concrete, epoxy and VCT are the core use, plus other durable sealed hard flooring. It is built to scrub and dry those surfaces in one pass. It is not a carpet machine: carpet needs a carpet extractor that injects and extracts water from the pile, which is a different tool. Match the machine to the surface — an auto-scrubber for hard floors, an extractor for carpet — and do not run a scrubber on carpet.

Does it really leave the floor dry?

It leaves it walk-dry, which is the point. The squeegee recovers most of the water immediately, so the floor behind the machine is dry enough to walk on far sooner than a mopped floor that has to air-dry. Be precise about it, though: it is not instantly bone-dry, and while the machine runs it is laying fresh water ahead of the squeegee. So the wet-floor window shrinks dramatically, but it does not disappear — you still manage the area you are actively cleaning.

Is it self-propelled?

No — this is a walk-behind model that you steer and push; the scrubbing and recovery are powered, but the drive is not. SUNMAX makes a self-propelled version and a ride-on version as separate, larger machines, so if you want powered forward drive for very large floors, those are different models. For most walk-behind work this pushes easily enough on a flat hard floor, but factor its weight into ramps, thresholds and transport.

How much floor justifies a scrubber?

The more large, open hard floor you clean on a regular schedule, the faster a scrubber pays back against mopping labor and the better the result. Think warehouses, retail, schools, gyms, hospitals and big lobbies. If your hard floor is small, broken up by fixtures, or cleaned only occasionally, a mop and bucket is cheaper and more practical — a 400-pound machine only earns its keep where there is real square footage to cover.

Does it need operator training?

Yes. It is a heavy, powered machine, so operators should learn to steer it, control the squeegee, manage solution flow, empty and refill the tanks, and charge the battery safely before running it in a live space. It is not difficult, but an untrained operator can leave streaks, miss water, or damage the machine or fixtures. Budget a short training session, and keep the charging and maintenance routine written down for whoever runs it.

Does it replace wet floor signs?

No. The walk-dry result means the floor behind the machine is safe much sooner than after mopping, which is a genuine slip-safety gain — but while the machine is running it is applying water ahead of the squeegee, and the area you are working is wet. So you still put out wet floor signs around the active cleaning zone. The scrubber shrinks the wet-floor window; it does not remove the need to sign it.

What is the SUNMAX 22 scrubber not?

It is not a carpet machine, not a lithium-battery model (it is lead-acid), not self-propelled or ride-on (those are separate models), and not a mop replacement for small or cluttered spaces. It is a cordless walk-behind auto-scrubber for large hard floors that scrubs and squeegee-dries in one pass. Train operators, charge the lead-acid battery in a ventilated area, wear PPE with the cleaning chemical, and still sign the wet area while you work.