Floor Scrubber Battery Runtime: Lead-Acid vs LiFePO4 Shifts

Published 2026-09-29 - Improve Battery

A floor scrubber earns money in square metres per hour, and it stops earning the moment its battery gives up. Cleaning contractors know the rhythm intimately: the machine that starts the night strong finishes it slowly, the second shift waits on a charger, and the battery that was supposed to last the contract is fading by its second year. Runtime is therefore not one number but a curve over a shift and a decline over a life - and on both curves, the chemistry change from lead-acid to LiFePO4 rewrites the scrubber's working day. This manufacturer's range includes a floor sweeper battery line within its industrial motive products, and the comparison below is the one its buyers run.

Runtime within a single shift

Lead-acid's runtime curve sags. The scrubber's brush motors and vacuum draw steady current, and as a lead-acid battery discharges, its voltage falls with it: suction weakens, brush speed drops, and the operator compensates by slowing down - so effective cleaning rate falls well before the battery is empty, and the last hour of the shift is the least productive. LiFePO4's flat discharge curve holds voltage near nominal until the pack is nearly empty, which means the machine cleans at hour four like it cleaned at hour one, and then stops - a cliff instead of a slope, which fleet managers consistently prefer because it is plannable.

Usable capacity compounds the difference. A lead-acid scrubber battery planned at 50 percent depth of discharge delivers half its nameplate on a sustainable basis; a LiFePO4 pack planned at the 80 percent depth of discharge its ratings assume delivers eighty. Equal nameplates, roughly sixty percent more usable runtime from the lithium machine - or the same runtime from a smaller, lighter pack.

Runtime across the battery's life

The second curve is the crueller one. Lead-acid capacity fades with every cycle, and scrubber duty is daily cycling: a bank that delivered a full shift when new delivers a diminishing shift thereafter, until the contract's largest site no longer fits in one charge. LiFePO4's rating class - thousands of cycles at working depth of discharge, with this manufacturer's storage and motive datasheets publishing figures like 6,000 cycles or more at 80 percent DOD - stretches that fade across a contract-length horizon. The practical meaning for a cleaning contractor: the machine specified for the site still covers the site in year three.

Opportunity charging between jobs

Cleaning work is bursty: two hours on site, a drive, another site. Lead-acid discipline forbids the obvious move - topping up during the gap - because partial charging offends its charging regime and its watering schedule is a weekly ritual besides. LiFePO4 welcomes the top-up: charge during loading, during lunch, during the drive on a suitable setup, with no memory penalty. For multi-site contractors this changes fleet sizing itself - machines spend the day working and sipping, instead of working and waiting.

The maintenance and safety ledger

A lead-acid scrubber battery needs watering, terminal cleaning, and a charging area that tolerates gassing; multiplied across a fleet and a contract, that is scheduled labour with a name on the roster. A LiFePO4 pack needs none of it: no water, no acid, no corrosion creeping into connectors. In food, healthcare and retail environments - the scrubber's natural habitat - a sealed, non-gassing battery also simplifies where the machine may charge and store. These are not soft benefits; they are line items in the cleaning contract's cost model.

Running the numbers for your fleet

The comparison to run is cost per cleaned hour over the contract: battery purchase plus replacements, charger energy, maintenance labour, and the productivity slope of the fading bank, against the lithium pack's higher first cost spread over its longer, flatter life. Bring the duty data - sites per night, hours per site, shifts per week - and the fleet size, and a manufacturer can quote the pack and charger set against that profile. Contractors who have done this arithmetic once rarely do it twice: the second time, the answer is already in their fleet.

Sizing the pack to the site portfolio

Contractors rarely clean one site; the pack decision should be made against the portfolio's hardest regular night, not the average one. List the sites by area and machine-hours, identify the longest single-charge demand, and size so that demand sits inside the pack's comfortable working range with reserve for the battery's later years. That last clause is where lead-acid specifications quietly fail: sized exactly to the new-battery shift, they fall short as fade accumulates, and the shortfall appears mid-contract when renegotiation is impossible. A lithium specification with headroom - the pack loafing through the big site at 60 percent depth - converts the contract's whole term into the flat part of the runtime curve.

Chargers and turnaround in multi-shift operations

Where machines work back-to-back shifts, the charger becomes the pacing item. Lithium's higher charge acceptance shortens the turnaround between shifts, and opportunity charging during the crew's breaks can remove the second battery set entirely - a capital saving that belongs in the comparison beside the pack price. This manufacturer's charger range is published per platform precisely because the pairing matters: charge voltage matched to the pack, current matched to the turnaround the operation needs. When you request the fleet quote, state the shift pattern; the charger count is an output of that pattern, not an afterthought.

What operators notice first

Ask crews who have made the switch what changed and the answers are rarely about kilowatt-hours. The machine pulls the same at the end of the night. Nobody waters batteries on Fridays. The charger area stopped smelling of acid and the floor stopped corroding under the bank. One pack, one plug, a gauge that tells the truth. Runtime curves and cycle ratings are the engineering language for those experiences - and the reason a mature cleaning operation, once converted, treats the old chemistry the way it treats any other retired overhead: without nostalgia.

A note on smaller machines and walk-behind units

Everything in this comparison scales down as well as up. Walk-behind scrubbers and compact sweepers run smaller packs - often 24V-class systems, the same platform family as this range's 25.6V products - and their operators feel the lead-acid slope even sooner, because a small bank has no reserve to hide its fade. The lithium conversion on a compact machine buys the same flat curve and the same maintenance deletion, and the smaller the crew, the more the deleted watering-and-cleaning routine is worth per machine. When you assemble the fleet quote, include the compact units rather than converting only the flagships; mixed fleets keep mixed habits, and it is the habits - the watering round, the early-evening fade, the spare bank - that the conversion exists to retire.

One caution travels with the conversion at every size: confirm the machine's charger and any on-board charging electronics are part of the specification, and confirm the pack's weight against the machine's balance design where the original battery served as ballast. Both are one-line items in a proper quote, and both separate a conversion kit from a battery in a box.