A Wind-Driven Battery Charger (Aug, 1933)
There is a teenager in Malawi named William Kamkwamba who has a really excellent blog where he talks all about building one of these.
HOW TO CONVERT AN OLD AUTO GENERATOR INTO A Wind-Driven Battery Charger
By L. G. HEIMPEL
Professor of Agricultural Engineering, Macdonald College, Quebec, Canada
ANY thousands of farm folk are still dependent upon battery sets for their radio programs. To them the charging of storage batteries is still the greatest bugbear of the battery set. This homemade wind-driven charger is an economical solution of their problem; indeed, it is designed to take care of not only the battery of a single set but the batteries of a whole neighborhood. The farm boy who makes one of these in a community not served by high-line power can earn the cost of the plant and extra spending money in a short time.
The plant consists of a 6-volt automobile generator mounted on a turntable on a mast of piping as shown in the drawings. The generator is driven by a 6-ft. two-bladed wind wheel or rotor which is really a propeller of the airplane type, through a 3-to-l ratio gear drive. This is necessary to insure correct generator speeds. The plant is designed to produce a sufficiently high voltage to close the cut-out points of the generator in a wind of 10 miles an hour, though this will depend somewhat on the condition of the generator and the perfection of the workmanship in the propeller.
The generator may be one from a model-T Ford, a Chevrolet, Overland 4, or any light car made during the last ten years. It must be in good condition, and the cut-out and ammeter will be needed. The brackets or supports which hold the propeller shaft are of flat iron and can be made by any blacksmith. The bearings may be of wood, if desired, though care is necessary to make certain of good alignment in boring the holes for the shaft and in mounting the bearings on the supports, otherwise there will be too much friction. Hard maple or birch blocks are best for wooden bearings, and after they are made they should be boiled in linseed oil. A piece of 7/8-in. cold-rolled steel shafting is about right for the propeller, but other sizes will do equally well.
The generator is driven by the camshaft gear of the automobile engine, which is mounted on the propeller shaft and meshes with the regular generator drive gear on the generator shaft. The cam gear will have to be fitted to the end of the propeller shaft in a machine shop, though this is a simple operation. With a little ingenuity a sheet metal cover can be made to protect the gears and to provide an oil bath for them. However, the writer knows of several outfits which have been running dry for several months, yet the gears show little wear.
The turntable is mounted on a 1-in. pipe flange into which is threaded a piece of 1-in. piping about 18 in. long. The inner mast is slipped into the mainmast, which consists of l-1/4-in. piping. The length of this mast depends on the nature of the building or derrick on which the outfit is to be mounted, but the design shown may be used under almost any conditions.
The requirements, of course, will vary somewhat with the circumstances under which the plant must operate. There may be some differences between the generator employed, for example, and that used in the plant described, which is from a model-T Ford. The distance between the generator and the battery should never be more than 50 ft.