Wheelys are aimed at being organic cafes on wheels, serving coffee, cold drinks and vegetarian snacks. The bikes are bought outright by an operator, who then pays a monthly franchise fee for use of the Wheelys brand, access to marketing materials, business support, discounted prices on coffee and supplies and various other benefits.

Dubbed the "Green Warrior," the Wheelys 4 has most of the required features that were already built into the previous models. Wheelys says the aim for this version was to improve some of the features and add new features that had previously not been possible.

The bike took 6-7 months and two prototypes to create. Co-founder and CEO of Wheelys Maria De La Croix explained to Gizmag that designing the bikes isn't just a case of writing a wishlist and then building them. Instead, it involves balancing key needs, weight, size and potential additional features, with some things having to be prioritized over others.

The Wheelys 4 was tested and developed on the principle that, under normal circumstances, it should be able to work independently for eight hours using a only car battery. The bikes each have two car batteries, meaning one can be used while the other is being charged, either from the mains or from the solar panels and optional windmills that the bikes have.

"Most people charge the batteries fully during the night," says De La Croix. "This means that there is no need for the solar panels during normal circumstances, but the cafe is built to work of the grid, even in remote areas where electricity is scarce. Also, many of our Wheelers take pride in using only solar to run their cafes."

The solar panel is able to generate up to 40 W of energy and the windmill up to 200 W. During the daytime, using minimal appliances, De La Croix says it's possible to run the bike of almost as little as 20 W. Even with the bike at full tilt, though, using the lights, speakers, thermos heaters, refrigerator, water pumps and other electrical draws, it is said to only require 60 W.

Energy usage obviously varies depending on factors like how hard the fridges have to work, how long the lights are used for and how loudly music is played. To keep energy consumption to a minimum, though, as many 12 V components are said to be used as possible, including the LED lights and other energy efficient pieces of kit.

The coffee itself is primarily drip-filtered, as this as a fast brewing process that still gives the barista time to explain what is happening and talk about the beans during the process. Wheelys also says this is a widely appreciated coffee style. Siphon-brewers, manual espresso makers and flasks with pre-brewed coffees are also carried.

The setup is modular and able to be tailored to the individual operator's requirements. By way of example, De La Croix explains that operators in Finland, where thermos coffee is popular, may need up to 20 l (4.4 gal) more thermos coffee than elsewhere, whereas in Hong Kong, they may need need a bigger freezer to facilitate popular iced coffees.

Tanks on the Wheelys 4 carry up to 20 l (4.4 gal) of fresh water, which is sufficient for around 200 cups of coffee. There's also space for additional water bottles and thermos flasks if needed. A gas stove is used to heat the water needed for brewing and taps, with three burners allowing for quick access to hot water at all times.

All the coffee residue produced in the brewing process can be recycled. The coffee grounds are able to be turned into soil cubes with flower seeds mixed in, which can then be planted.

In addition to being able to produce coffee in a green, clean way, the Wheelys 4 also has an air filter with which it is able to clean the surrounding air. De La Croix says the filters are able to purify 400 cu ft (11 cu m) per minute, or 240,000 cu ft (6,796 cu m) per workday. With an distributed network of 500 Wheelys cafes expected to be in operation soon, the company sees this as a powerful way it can help cities while dishing out caffeine hits.

An Indiegogo crowdfunding campaign for the Wheelys 4 mobile cafe is under way. At the time of writing, individuals who pledge from US$3,599 can receive one of the mobile cafes, assuming all goes to plan with the roll-out. Delivery is expected in May.

Gizmag