I think it is a cool idea to build a generator from a lawn edger motor, so much so that a few years ago I build a very similar generator from a lawn mower engine. It works well, and was pretty simple to build
I would imagine, from my experience on the similar project, that a man could do this in a single day if they had the materials close at hand.
The basic generator (gas powered motor, alternator and battery only), can be used as a 12 volt power source. This is extremely useful for charging battery banks in RVs, campers or in out buildings. The big advantage to this generator as a charging system is the high current output of the alternator, and thus, the reduced charge time over using solar cells, or AC battery chargers.
The other big advantage to using this unit to charge batteries over just charging them with a car, is that this generator uses much less gas to do the job (which is critical in an emergency). Some HAM radio folk use 12 volt equipment that can be powered from the battery until it is low in charge, and then crank up the generator to recharge the battery. The high output of this unit also makes it useful for car lots or fleets for jump starting cars.
If a DC to AC power converter is added to the basic system, then a limited amount of 120 Volt AC power would also be available! DC to AC power converters electronically convert the 12 volt DC power to 60 hertz AC power at 120 volts. These boxes just connect to the battery on the generator, and provide AC power outlets for standard household AC power.Build a Generator From a Lawn Edger Motor