WORX Nitro HydroShot 20V (WG633E)
Best overall for mixed car, bike and remote cleaning.
Choose this instead of the Ryobi RY18PWX41A-140 when the WORX combination of a manufacturer-published 42 bar maximum pressure and 220 L/h maximum flow is more useful to you than Ryobi's three selectable pressure stages. Both are complete 4.0 Ah kits and both can siphon from portable water sources, so the decision is mainly about their published hydraulic specifications and control layouts rather than basic off-grid capability.
Before you choose: It still needs a separate water container for tap-free cleaning, unlike the Bosch Fontus 18V-6 with its integrated tank. Its pressure and flow figures are manufacturer specifications rather than independent cleaning measurements.
More details
The WG633E combines a 6 metre suction hose with bottle and container compatibility, so it can work where neither a tap nor mains electricity is available. The selected UK kit also includes a 4.0 Ah battery and charger, avoiding the extra power-system purchase required by several bare-tool alternatives. Pros: Complete 4.0 Ah battery-and-charger kit; Can siphon from buckets and other portable water sources; High published pressure and flow for this portable class. Consider: No onboard water tank; Requires a separate container when used away from a tap. Limitation: The 42 bar maximum and 220 L/h flow are published specifications, not independent test results. Buyers wanting an all-in-one water tank should consider the Bosch instead.