75 Watt DC Hand Crank DC Generator
This generator will harnesses a readily available source of renewable energy – Human Power. It is user friendly, portable, and available whenever you have the need for it. The power output is directly proportional to the effort put into it. The Human Power Generator can be a valuable tool in teaching an appreciation of the power we often take for granted.
• Emergency power generation and 12V battery charging. Charges at between 3-5 amperes.
• Ideal for powering or charging small devices.
• Remote or off-grid power for 12-volt water pumps and small appliances.
• Independent radio or radiotelephone systems; emergency communications.
• Classroom projects and educational exhibits to demonstrate the physical effort required to generate electrical power.
The Human Power Generator is a 12V DC power source primarily designed to charge a 12V battery. It will charge at a rate of between 3-5 amperes. It will provide a maximum of 75 watts. Sustainable power output over a period of time is between 40 to 65 watts. It is ideal for low power appliances like laptops, radios, lighting and other small devices. AC appliances can also be powered by the Human Power Generator when a DC/AC inverter, connected to the battery (often in the form of a portable power pack), is used.
CLICK ON IMAGE BELOW TO ROTATE IT AND SEE DIFFERENT ANGLES
It is possible to directly power certain DC appliances without using a storage battery. It is important to observe maximum voltage ratings. An appliance rated for 12V DC will be damaged if too much voltage is delivered. For example, a 12V light bulb may be able to absorb 13V momentarily but any more voltage would cause the bulb to burn out and fail. We recommend that DC Direct applications be voltage regulated or closely monitored with a dc voltmeter or multimeter to accurately measure output. The HPG can produce up to about 16V when connected to the load in short bursts if the pedals or hand cranks are given a very quick turn. Note: Our 12V Educational Light Box is voltage regulated.
This generator can be used as a pedal power generator by doing the following:
- Install bicycle pedals onto cranks
- Set generator on floor
- Put a chair next to the generator
- A person sits in the chair and pedals with their feet.
While human beings vary widely in weight, strength, and endurance, the average amount of pedal (leg) power that a person can generate is about 65 watts, or just under one-tenth of a horsepower. The average sustainable output will fluctuate. For example, it may be easy to produce 65 watts continuously for twenty minutes, but that output may drop down to 30 watts as the person pedaling becomes tired. That said, 75 watts or slightly more may be produced in short bursts if the pedal or hand crank is whipped around very quickly (not recommended). We recommend bolting the Human Power Generator to a base for stability.
Hand Crank Power
The available power using hand cranks is less due to the smaller muscle mass of the upper body. The maximum output is about 50 watts and the average sustainable output is around 35 watts.
Below you will see the names of the parts that make up the 75 Watt portable hand crank generator.
A connecting cable should be used that contains a full wave bridge /diode in a sealed aluminum case (see left) to prevent reverse current from traveling back from the battery or motoring of the Human Power Generator.
The full wave bridge will also provide a consistent polarity output that is not dependent on the direction of rotation. In other words, this allows the user to pedal in either direction safely with equal results. Cable should be 16 AWG (American Wire Gauge) size wire. This is the same size wire as most 3 pronged extension cords.
Note: The only cable used with the Human Power Generator that does not have an in-line diode is the cable used with the 12VDC Educational Light Box or the Power View Monitoring software, as the diode is built into both of these products.
The Human Power Generator can charge any 12V battery but is most commonly used with a low Ah (under 20 “ampere hours” of capacity) deep cycle 12-volt battery, such as the type used in Portable Power Packs. WARNING: This must be done with the use of an inline fuse to avoid accident or injury! High quality fuses are available at local auto parts store.
To charge a battery, a DC power source of a higher voltage than the battery is connected to the battery, positive to positive and negative to negative. As long as the charging source is of higher voltage than the battery, current will flow into the battery until it is fully charged.
If the voltage of the charging source is less than the battery voltage, current will not flow into the battery even though the charging source may be capable of supplying power. The Human Power Generator will not deliver a charging current to a battery until the generator is turning fast enough to develop a voltage higher than that of the battery. Consequently, very little effort is required to start pedaling, but as soon as the generator voltage exceeds the battery voltage, a greater mechanical resistance is felt as power begins to be transferred into the battery. As the battery becomes fully charged, the mechanical resistance decreases.
The average charging current with the HPG is between 3-5 amperes.
A 12V battery with lower ampere hour capacity will take less time to charge. A battery with very high Ah, like a car battery with 200 Ah, would take a very long time to charge.
Battery Charging Risks
It is important not to overcharge the battery. Overcharging can cause the battery to heat up and possibly release hydrogen gas. This can damage the battery and create a hazardous condition. This is a rare occurrence and charging with the HPG is a relatively slow process, however, it is important to monitor the level of charge in the battery regardless.
The Power Pack has a built-in voltage indicator allowing you to monitor the charge status of the battery. If the indicator lights show that the battery is full, stop charging.
If you are using the Human Power Generator with your own battery, monitor the battery voltage to prevent overcharging. A simple voltmeter can be used to measure output and battery voltage with certainty. A fully charged 12V battery will read between 12.7 to 13.3V.
Keep loose clothing, hair, hands, toes, fingers, and pets away from the drive chain and sprockets of the Human Power Generator at all times.
Do not operate the Human Power Generator barefoot.
If your Human Power Generator is assembled with foot pedals, do not operate it with your hands.
Do not allow children to operate the Human Power Generator unsupervised.
The generation of electricity requires a certain amount of physical exertion. People with health considerations should consult with their health care practitioners before engaging in strenuous cranking or pedaling.
As with any electrical device, use caution with the Human Power Generator. Although the voltage generated is low, take care not to touch any exposed wires or to allow loose wires to touch each other.
Observe the polarity – positive and negative – of all connections.
Do not expose the Human Power Generator to water or spray.
Generator Handling Precautions
This generator must be carried by the base – not picked up by the safety cover.