When a battery-powered, driving-style steam cleaning machine goes onto the purchase list, the buyer usually has to defend the decision to three different people: the operations lead who cares about throughput, the facilities or safety manager who cares about electrical risk in a wet bay, and the finance reviewer who wants to know why this unit costs more than a pressure washer. “It runs on a battery” is not a specification. Write down what has to be true before the machine is accepted, and you can compare units from different suppliers on the same sheet.
That is the point of defining measures up front. The PowerDe PWD01 steam cleaner (including battery) gives you a concrete example to test the method against, because its published specification sheet answers some of these measures directly, is silent on others, and lists one item — the battery — as customer supplied. Each gap in the sheet becomes a question in your RFQ.
1. Coverage per shift, measured in bays or vehicles, not in square metres
Steam and hot-water machines are usually bought to keep a wash line moving, so the first measure should be written in the unit your operation already plans around: cars per hour in a car-wash bay, vehicles per shift in a depot, or linear metres of a wash line completed in a working day. Then break that target into the parts that actually consume time — travel distance between wash positions, machine setup, and actual spraying time.
This is where a driving-style machine is different from a hand-pushed one. The PWD01 is listed as an autonomous-driving mobile unit with machine dimensions of 2,500 × 900 × 1,050 mm, described for indoor garages and narrow outdoor parking spaces. A measure worth writing into your specification is a travel test: how far an operator can move the machine, loaded, between two working positions in your own layout, and whether that movement needs a second person. Ask the same question of every model you evaluate, and record it, because “mobile” means very different things across the category of PowerDe cleaning equipment.
2. Mode coverage: does one machine do hot water, wet steam, and dry steam?
A single job site rarely needs only one cleaning mode. Engine bays and greased floors behave differently from painted surfaces, and a mode that suits one leaves the other wet. So instead of asking “is it powerful”, ask a countable question: how many distinct cleaning modes does the machine provide, and can the operator change between them without stopping the job or refilling the tank.
The PWD01 specification lists three cleaning modes — hot water, wet steam and dry steam — with a high-pressure water gun and nozzle as the cleaning method, and a vacuum cleaner with a flat nozzle working into a sewage tank. For your measure sheet, translate that into a short list of your own tasks (engine compartment, floor grease, painted bodywork, interior surfaces) and require the supplier to say which mode handles each. If a task has no mode, the machine does not cover your scope, no matter how good the headline heating figure looks.
3. Water tank and refill frequency: the hidden interruption in every shift
Cleaning machines are rated by output, but crews are interrupted by consumables. Define the measure as refill events per shift, not tank litres alone. Take the tank volume from the datasheet, then ask for the water consumption per hour for each mode, and divide. If the supplier cannot give consumption per hour, make that an explicit line in the trial plan: run the machine for one hour in each mode you buy it for, and log how many times you fill it.
The PWD01 lists an 80 L clean water tank with a tap-water inlet using a 4-point internal-tooth fitting, plus a sewage tank served by the vacuum function. Two practical measures follow from that: whether your existing water point can connect to the inlet fitting without an improvised adapter, and how often the sewage tank has to be emptied in your layout. Emptying frequency is the kind of measure nobody puts in a purchase order and everybody argues about after the machine arrives.
4. Battery interface: since the battery is customer supplied, write the interface as a specification
On the PWD01 (including battery) page, the working voltage line reads 48 V mobile battery with the remark that batteries are customer provided. That single line should change how you write your specification, because it splits one product into two supply responsibilities. For any battery-driven machine you evaluate, define these measures:
- Working voltage and connector type, matched to the packs you already own or can source locally.
- Runtime per charge measured in your own cycle — machine moving, heater on, gun in use — not an idle figure.
- Charge time and the charger specification, and whether charging can happen between shifts rather than during them.
- Where the battery is warrantied and serviced, and which party you call when the fault is on the pack rather than the machine.
- Whether the same pack can run other equipment in your fleet, which is often the best justification for standardising on 48 V.
If your team already runs a fleet on one voltage, write that voltage into the RFQ as a requirement instead of accepting whatever the machine ships with. Standardising the interface is what keeps spare packs, chargers and training costs under control as you add units.
5. Safety protections you can verify during acceptance, not just read on a page
Wet environments and battery power together are what make safety managers hesitate. The right response is not to argue about risk in general, but to list the protections in the datasheet and then prove each one during acceptance. The PWD01 page lists leakage protection, short-circuit protection, high-temperature protection, high-voltage protection, water-shortage protection and high-voltage explosion-proof, with a PTC semiconductor heater named for heating.
Turn that into three verifiable measures. First, run the machine with a low water level and confirm the protection actually stops the equipment instead of only warning. Second, confirm how the machine behaves on your electrical supply, including how it is earthed and whether your residual-current protection trips. Third, ask what the machine does if the battery is disconnected mid-job, and how it is restarted. Write the pass criteria before the trial, so a demonstration that skips these steps counts as a failed trial rather than a good presentation.
6. Heated-water capability, stated as a figure and tested on your soil
The PWD01 specification lists 4.5 kW heating power with semiconductor heating. That number matters only because it drives how fast the machine reaches and holds the temperature you need — so do not use it as the measure itself. Make the measure a result: time from cold start to the temperature at which your usual soil is removed without scrubbing, tested on a sample of your own surfaces.
This is also where you should keep the specification honest. Some PowerDe models publish steam temperature and steam pressure on the detail page, and some — the PWD01 among them — do not. Where a figure is not published, do not carry an assumed value into your purchase document. Ask for it in writing, or measure it yourself in the trial and record the method you used, so the number can be compared against the next machine you test.
7. Service, spares and consumables: the measures that decide total cost
Finally define what happens after delivery, because for cleaning equipment this is usually where the real cost sits. Ask each supplier to commit, in writing, to the parts that wear: nozzles and hoses for the high-pressure gun, seals, the heater element, and the vacuum components. For a battery-driven unit, add the pack and charger to the same list and ask for the price and lead time of a replacement.
Then measure response. Ask how a fault is triaged, what a remote diagnosis covers, what the on-site response commitment is in your region, and how a spare is shipped. If you are buying more than one unit, ask whether the same consumables fit every model in the range you are considering — on the PWD01 the fitting is a 4-point internal-tooth joint, and a mismatch across models means carrying duplicate stock.
Putting the measures into a one-page acceptance sheet
A useful sheet has one row per measure, with the target you set, the value the supplier published, and the value your trial recorded. For a machine such as the PWD01 with battery, that sheet would carry roughly these rows: vehicles or bays per shift; travel time between positions in your layout; which of hot water, wet steam and dry steam covers each of your named tasks; refills per shift and sewage emptying per shift; runtime per charge on your cycle and charge time; confirmation of each protection listed on the datasheet; cold-start time to working temperature on your soil; and the price and lead time of wear parts, pack and charger.
Write those rows before you request a quotation, and send them to every supplier with the same request: fill in the published value, and state what you will demonstrate during a trial. As a working example of how a written specification reads, the PWD01 product page shows what PowerDe publishes for this model, including its dimensions, three cleaning modes, 80 L clean water tank and 48 V battery working voltage. Where a supplier's answer is blank, you have identified a real gap — not a reason to assume the number, and not a reason to reject the machine either.
Two things decide whether this exercise pays off. The measures have to be in units your own team can observe, and the trial has to happen in your facility with your soil. A supplier that fills in your sheet and runs the trial in your building is showing you the machine you will actually own. If your scope spans more than washing vehicles, send that scope to the manufacturer with the sheet attached; contact PowerDe and ask which model in the cleaning range matches each task, and what would need to be customised.
