Thats a very slick and finished unit. Its pretty easy to do cheaply though. The system I made is simply a PM motor (an old Corvette radiator fan motor) hooked through a diode to prevent the battery from running the motor. You simply pedal the excercycle until the motor is generating more voltage than the battery. No regulator or anything. Want more amps: Pedal harder. You will have to keep an eye on the voltage so that you don't exceed the batterys max charging voltage.
Its best to use a bicycle on a training stand that normally has fans or some other type of resistance device. I replaced that device with the motor wired in my diode and wired the output to the batteries. I also have a couple of 12V halogens and a fan connected for extra load if my batteries are full. Having gears is necessary because you will occasionally want to do training at different loads or cadence speeds and the motor/generator will increase load requirements through a narrow band of motor rpms.
When my batteries are low I can maintain 5 to 8 amps for an hour which is not too much but remember there are other losses such as tire resistance on the friction roller and the cooling fan (for the engine... Me). The first motor I used burned out its bearing in only 30 hours or so. It was not designed for large hanging loads. Use a quality motor with a ball bearing on the front end, No bushing motors, and keep the shaft as short as possible unless you can support it on the far end of the friction roller.
I'll attach a couple of pics. The first is while using the incandesant loads. 125 watts of light + 50 watts driving the fan pointing at my chest. Usually thats a little too much load for a long session but 5 to 8 amps +the fan is ok for an hour. The second is the mechanicals you can see the motor in the back going up to the capacitor for cutting ripple. The batterys are in the shoebox. Just in front of that is a 9 led voltage meter. The diode is a stud mount by the cap. From there the wires go to switches that control how many lights if any are needed for load. With no light load all the power goes into the batts.
Simple and useful
Rick Miller
