Floor Scrubber Battery Runtime Data: Hours per Charge by Amp-Hours, Draw and Chemistry
Modeled floor scrubber runtime by battery amp-hours and current draw for lead-acid and lithium, with coverage per charge, charging cost and cost per hour.
Key takeaways
- Runtime is usable amp-hours divided by average current draw; a 24V 240 Ah lead-acid pack at 40 A gives about 3.8 hours in the Scrubber Guide model.
- Lithium delivers about 36 percent more usable runtime from the same rated Ah because it tolerates deeper discharge and loses less capacity at high draw.
- Brush down pressure and vacuum mode are the biggest runtime levers you control after purchase.
- Electricity is cheap, often under $1 per charge; battery wear per hour and labor are what matter.
Floor scrubber battery runtime equals the usable amp-hours in the pack divided by the machine's average current draw. In the Scrubber Guide model, a 24V walk-behind with a 240 Ah lead-acid pack drawing 40 A runs about 3.8 hours; the same rated capacity in lithium (LiFePO4) runs about 5.2 hours. Most lead-acid walk-behinds land in the typical 2 to 4 hour range.
Manufacturers quote runtime under their own test conditions, often on the lowest power setting. This page shows how runtime is actually calculated, gives tables for lead-acid and lithium across common pack sizes and draws, and quantifies what shortens it in the field. For a single machine, the battery runtime calculator runs the same math.
Methodology
All runtime figures are Scrubber Guide estimates.
- Rated Ah is the capacity printed on the battery, usually at the 20-hour discharge rate for lead-acid. Batteries in series add voltage, not Ah: four 6V 240 Ah batteries make a 24V 240 Ah pack.
- Usable depth of discharge (DoD): 0.80 for lead-acid. Running deep-cycle lead-acid flat shortens its life sharply, and most scrubbers have a low-voltage cutout that stops the brush near this point. 0.90 for lithium, which tolerates deep cycles and whose battery management system protects the bottom of the range.
- Rate derating: lead-acid delivers less than its 20-hour rating when drained in 2 to 4 hours (the Peukert effect). We use 0.80. Lithium is far less affected; we use 0.97.
- Combined factors: lead-acid 0.80 x 0.80 = 0.64 of rated Ah; lithium 0.90 x 0.97 = about 0.87.
- Average draw is the total current from brush motor(s), vacuum motor, drive motor, solution pump or valve and controls while scrubbing. It is not the peak.
- Assumed temperature: room temperature, roughly 70 to 80 F (21 to 27 C). Cold storage and freezer work reduce capacity, lead-acid more than lithium.
- New batteries. Many batteries are considered at end of life when they hold about 80 percent of original capacity, so an aging pack can deliver 20 percent less than these tables.
Where the amps go: a typical 20 in, 24V walk-behind
| Component | Approximate power | Approximate draw at 24V |
|---|---|---|
| Brush or pad motor, normal pressure | 400 W | 17 A |
| Vacuum motor | 400 W | 17 A |
| Traction drive | 120 W | 5 A |
| Solution valve or pump, controls | 40 W | 2 A |
| Total while scrubbing | about 960 W | about 40 A |
These are Scrubber Guide illustrative values for a mid-size machine, not specifications for any model. The point is the shape: brush and vacuum dominate, and the brush is the part that changes with how hard you press. Turning on heavy down pressure can add 5 to 15 A on its own (see down pressure).
Typical average draw by class (our estimates)
| Machine class | Typical system voltage | Average scrubbing draw |
|---|---|---|
| Micro and compact | 12V to 24V | 10 to 25 A |
| Small and mid walk-behind (17 to 24 in) | 24V | 30 to 45 A |
| Large walk-behind (26 to 34 in) | 24V or 36V | 40 to 60 A |
| Ride-on and stand-on | 24V or 36V | 50 to 80 A |
Results table 1: lead-acid runtime by Ah and draw
Hours of scrubbing per full charge, combined factor 0.64.
| Rated Ah | 25 A | 35 A | 45 A | 60 A | 80 A |
|---|---|---|---|---|---|
| 100 Ah | 2.6 | 1.8 | 1.4 | 1.1 | 0.8 |
| 130 Ah | 3.3 | 2.4 | 1.8 | 1.4 | 1.0 |
| 160 Ah | 4.1 | 2.9 | 2.3 | 1.7 | 1.3 |
| 200 Ah | 5.1 | 3.7 | 2.8 | 2.1 | 1.6 |
| 240 Ah | 6.1 | 4.4 | 3.4 | 2.6 | 1.9 |
| 310 Ah | 7.9 | 5.7 | 4.4 | 3.3 | 2.5 |
| 400 Ah | 10.2 | 7.3 | 5.7 | 4.3 | 3.2 |
Results table 2: lithium (LiFePO4) runtime by Ah and draw
Hours of scrubbing per full charge, combined factor 0.87.
| Rated Ah | 25 A | 35 A | 45 A | 60 A | 80 A |
|---|---|---|---|---|---|
| 100 Ah | 3.5 | 2.5 | 1.9 | 1.5 | 1.1 |
| 130 Ah | 4.5 | 3.2 | 2.5 | 1.9 | 1.4 |
| 160 Ah | 5.6 | 4.0 | 3.1 | 2.3 | 1.7 |
| 200 Ah | 7.0 | 5.0 | 3.9 | 2.9 | 2.2 |
| 240 Ah | 8.4 | 6.0 | 4.7 | 3.5 | 2.6 |
| 310 Ah | 10.8 | 7.7 | 6.0 | 4.5 | 3.4 |
| 400 Ah | 14.0 | 10.0 | 7.8 | 5.8 | 4.4 |
Comparing the two tables, lithium gives about 36 percent more runtime from the same rated Ah. That is why lithium packs are often sold with a lower Ah rating than the lead-acid option for the same machine and still quoted at similar runtime. Compare usable Ah, not printed Ah. The full trade-off is covered in lithium vs lead-acid.
Results table 3: coverage per charge
Runtime only matters as area cleaned. Multiplying runtime by practical productivity from our productivity benchmarks gives a conservative coverage per charge (conservative because the 0.65 efficiency factor includes tank stops when the battery is idle).
| Machine | Practical sq ft per hr | 2 hr runtime | 3 hr runtime | 4 hr runtime |
|---|---|---|---|---|
| 20 in walk-behind | 11,400 | 22,800 | 34,200 | 45,600 |
| 28 in walk-behind | 15,900 | 31,800 | 47,700 | 63,600 |
| 32 in ride-on | 31,200 | 62,400 | 93,600 | 124,800 |
| 40 in ride-on | 39,000 | 78,000 | 117,000 | 156,000 |
Decision rule: if your nightly area exceeds about 80 percent of the coverage per charge, you are one cold night or one aging battery away from not finishing. Size for headroom, add a second pack, or choose a chemistry that allows opportunity charging.
Sensitivity: what shortens runtime in the field
Base case: 24V, 240 Ah lead-acid, 40 A draw, 3.8 hours.
| Change | Runtime | Change vs base |
|---|---|---|
| Heavy down pressure adds 10 A | 3.1 hr | -20 percent |
| Eco or quiet mode cuts draw 25 percent (to 30 A) | 5.1 hr | +33 percent |
| Pack aged to 80 percent capacity | 3.1 hr | -20 percent |
| Undercharged (charger interrupted at about 80 percent) | about 3.0 hr | about -20 percent |
| Same rated Ah in lithium | 5.2 hr | +36 percent |
| Cold area cleaning, lead-acid (our rough estimate) | 2.9 to 3.5 hr | -10 to -25 percent |
Several of these stack. An older lead-acid pack, used with heavy pressure, after a short charge, in a cool warehouse, can easily deliver half its brochure runtime. When operators report that "the batteries are dying," it is often this combination rather than one failed battery.
Charging energy and cost
Electricity is a small cost. We assume $0.15 per kWh, about 80 percent charging efficiency for lead-acid and 92 percent for lithium.
| Pack | Stored energy | Grid energy per full recharge | Cost per charge |
|---|---|---|---|
| 24V 130 Ah | 3.1 kWh | about 3.1 kWh | about $0.47 |
| 24V 240 Ah | 5.8 kWh | about 5.8 kWh | about $0.86 |
| 36V 310 Ah | 11.2 kWh | about 11 kWh | about $1.65 |
| 36V 400 Ah | 14.4 kWh | about 14 kWh | about $2.15 |
At 260 charges a year, even the largest pack here costs under about $600 a year to charge.
Battery wear cost per hour
The real cost of running on battery is wear. Assumptions (Scrubber Guide estimates, approximate): replacement 24V lead-acid pack $1,000 to $2,000 and 500 to 1,500 cycles at about 3 hours per cycle; comparable lithium pack $3,000 to $6,000 and 2,000 to 5,000+ cycles at about 3.5 hours.
| Scenario | Pack cost | Cycles | Wear cost per scrubbing hour |
|---|---|---|---|
| Lead-acid, poor care | $1,200 | 600 | about $0.67 |
| Lead-acid, typical | $1,500 | 800 | about $0.63 |
| Lead-acid, excellent care | $1,200 | 1,200 | about $0.33 |
| Lithium, conservative | $4,500 | 2,000 | about $0.64 |
| Lithium, typical | $4,500 | 3,000 | about $0.43 |
| Lithium, long life | $4,500 | 4,000 | about $0.32 |
Lithium's higher price is largely offset by cycle life, and the comparison leaves out lead-acid watering labor, acid spills and the cost of a missed shift. On the other side, a site cleaning only a few times a week may never use lithium's full cycle life before the machine itself is retired. Good battery maintenance is what moves lead-acid from the top rows to the bottom.
What this means
- Ask for usable runtime at your settings. Request runtime at normal down pressure with standard vacuum, not eco mode.
- Size the pack to the route plus 20 percent. Use the coverage table above, then add margin for aging and cold.
- Charge lead-acid fully, every time. Partial charges and opportunity charging shorten flooded lead-acid life. Lithium tolerates topping up during breaks.
- Use eco modes where soil allows. A 25 percent cut in draw is a third more runtime for free.
- Track it. Log runtime per charge monthly. A steady decline is the earliest warning that a lead-acid pack needs equalizing, watering attention, or replacement. More detail in floor scrubber batteries.
Frequently asked questions
How long does a floor scrubber battery last per charge?
Lead-acid walk-behinds typically run 2 to 4 hours of scrubbing per charge. Lithium packs of similar rated capacity usually run longer, and riders range widely depending on pack size and draw.
How do I calculate floor scrubber runtime?
Multiply rated Ah by about 0.64 for lead-acid or about 0.87 for lithium, then divide by the machine's average current draw in amps. That is the Scrubber Guide model and it gives a realistic planning number.
Why does my scrubber run shorter than the brochure says?
Brochure figures are often measured on low settings with new, fully charged batteries. Heavy down pressure, aging cells, incomplete charging and cold temperatures each cut runtime, and they often combine.
How many years does a floor scrubber battery last?
At one cycle per working day, lead-acid at 500 to 1,500 cycles typically lasts about 2 to 6 years depending on care. Lithium at 2,000 to 5,000+ cycles often lasts as long as the machine.
Does it cost much to charge a floor scrubber?
No. A typical walk-behind pack costs well under $1 per full charge at $0.15 per kWh. Battery wear and the labor around charging matter far more than electricity.