Mobile detailing power planner

What size generator do you need for mobile detailing?

It depends on the tools you run at the same time, not on the biggest tool you own. Add the running watts of every tool in a stage. Then add the extra watts a motor needs for a moment as it starts. The generator must cover both: its running rating for the stage total, and its starting rating for the largest start.

Use the figures from the label or manual of your exact tools. Two vacuums or pressure washers of the same type can need very different power. A generic wattage chart is a guess, so the planner never fills one in for you.

The calculation

• Stage running load = the running watts of every tool in that stage.
• Start event = one tool's starting watts + the running watts of the other tools in its stage.
• Largest start = the biggest start event in any stage. If a tool has no starting figure, the start check stays unknown, unless the known part alone is already over the rating.
• Power station energy = each stage's running load × its minutes, added up, compared with 80% of the rated watt-hours.
• Outlet limit = 120 volts × the circuit's amps: 1,800 for 15 amps, 2,400 for 20 amps.

Worked example

These are example inputs from our generator guide, not figures for real tools. A vacuum runs at 900 watts and needs 1,500 to start. An extractor runs at 1,400 and needs 2,500 to start. A 60-watt work light stays on through both stages.

The vacuum stage runs at 960 watts and peaks at 1,560 when the vacuum starts. The extractor stage runs at 1,460 watts and peaks at 2,560 when the extractor starts. A generator rated 3,000 running and 3,300 starting covers both stages.

If the vacuum is still on when the extractor starts, the peak is 900 + 60 + 2,500 = 3,460 watts. That is 160 watts over the starting rating. Write the order on the job sheet: switch the vacuum off before you start the extractor.

Start one motor at a time

Honda's generator sizing advice is to start high-demand equipment at different times, so the starts do not add up. The planner assumes one motor starts while the others in its stage are already running. If two motors could start together, add both starting figures yourself.

Generator, power station, or the customer's outlet

• Generator: check its running and starting ratings, its outlets, and that you have a safe outdoor place to run it at every address.
• Battery power station: check its continuous output, its surge output for motor starts, and its stored energy for the time you work. It needs a charging plan.
• Customer's outlet: needs permission, a circuit with room for your load, and a cord that suits your tool. A result under the limit is not a pass, because other devices may share the circuit.

Labels that show amps

Many tools list amps, not watts. For a single-phase tool, volts × amps gives volt-amperes. True watts are equal or lower, so using volt-amperes as running watts errs on the high side, which is the safe side for sizing. Amps do not tell you the starting demand. Ask the maker for it.

Run a generator outdoors only

A fuel generator can cause fatal carbon monoxide poisoning. The U.S. Consumer Product Safety Commission says to use generators outside only, at least 20 feet from homes, with the exhaust facing away, and never inside homes or garages, even with doors and windows open. Treat a van or trailer the same way: never run a generator inside one. If a job site has no safe place to run it, the generator fails that job.

Sources and limits

Honda explains running and starting wattage and starting large loads at different times. EcoFlow's runtime guide separates capacity, continuous output, and surge, and gives 0.80 to 0.90 as a first-pass AC efficiency. Schneider Electric gives the volts × amps formula and notes that watts also need the power factor. The CPSC carbon monoxide page gives the outdoor and 20-foot rules. Sources reviewed October 14, 2026.

The planner compares numbers you enter. It does not approve a generator, outlet, cord, or job site. Check every rating against the manuals and test the real sequence before a paid job. Then plan the rest of the van or trailer with the mobile setup guide and the water tank planner. For steam cleaner and vacuum watts, see the steam cleaner comparison and the vacuum comparison.

Electric pressure washers for mobile detailing, compared

A washer on your own power and water passes three checks: the current it draws, the water supply its maker asks for, and tank feed. The table shows what the manuals and spec pages of nine models state.

• Tank feed: only the Kränzle K1622TS documents drawing water from a container by suction, with a lift and hose limit. The Kärcher K 5 Premium (1.603-361.0) sheet lists water suction hoses but gives no lift. The Ryobi RY142300 manual says the water must come from a water main. The rest state a minimum flow or inlet pressure, or nothing. To feed one of those from a tank, check that your pump meets that flow and pressure. The 12-volt pump comparison shows each pump's flow at 40 psi.
• Power: four reach 1,800 W in the planner, the whole limit of a 15 amp outlet at 120 volts. Active, Kärcher, and Ryobi ask for a dedicated or individual branch circuit.
• Starting watts: only one maker publishes one: Active 2.0 (SE01), 3,000 W. For the others the start check stays unknown until you get the figure from the maker.
• Extension cords: three of the nine models do not allow one at all. Place the generator or outlet within the washer's own cord.

Planner watts are 120 volts × the highest current the maker's pages give. Volts × amps is at or above the true watts, so the figure errs high, which is the safe side for sizing. Active publishes its own generator figures, and the planner uses them. Where a maker's pages disagree on current, the table shows both. Some makers give max figures and others rated ones, so the two do not compare directly.

Water per 10 minutes is the listed flow × 10, with the trigger held. Use it with your own spray time in the water tank planner. The maker's minimum supply is a separate check: it can be higher than the washer's own flow.

Adding a foam cannon? Some cannon makers set a minimum flow above what several of these washers deliver. The foam cannon comparison checks each of these washers against each cannon maker's limits and orifice rule.

Sources: each model's manual, spec pages, and FAQ, linked in the table, read October 23, 2026. Nobody tested these machines for this table. For two set-up costs with hoses and warranty terms, see the pressure washer guide.

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