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Other Useful Information
Battery Charging
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.
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.