The biggest and most expensive unit we've used recently justifies itself with dual-power user friendliness and really well designed functionality. At nearly 10kg empty it’s not the easiest beast to lug around, but the 14.5-litre tank detaches for carrying or easy filling from a stream/pond. A filler filter cap means any pump clogging crap will get sieved out too.
The Neoprene side pouch comes off and the car power cable can be bundled into the battery compartment for safe storage. The battery itself is a standard L-shaped 18V power tool cell, which can be removed and stuck into a desktop charger while your dirty washer stays outside. There’s enough juice to spray through four full tanks of water, so you should be fine for even the filthiest 24-hour race. Soft grip sections and a firm clip action from the sturdy, cleanly moulded plastic clasps give a real quality feel to the whole unit.
The hose can be plugged into itself to stop drips and the electrics are kept a long way from the wet bits. Bayonet attachments and a swivelling joint at the tank end reduce the chance of accidental damage and kinking too. Its spray power is marginally better than some we've tried, but you’ll still have to get some cleaning fluid and/or a brush/rag involved to get your steed sparkling.