Specifications

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Figure 12 - Charging Stages
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With the general understanding of what to look for in a charging circuit we can now look
to see how the specified battery will react to the previously discussed charging
methods. The battery chosen with a capacity of thirty eight amp/hour would then have a
bulk charge state of one hour and thirty minutes with an average charge of twenty five
amps to bring the battery from zero percent capacity through the bulk stage of the
charging process to around ninety percent capacity. Because of the fickle nature of the
generators as they are dependent on ever changing variables the charge time of the
generator deployed outside in the elements would also have to take into account the
changing charging amperages as well as temperature of the surrounding environment
and could greatly fluctuate with a multitude of given circumstances. After the charging
current falls below one amp in this state the charging circuit will have to switch over to a
constant current of two amps for one hour to complete the charge.
The voltage on the battery at this point should be around fourteen volts and will be a
satisfactory cut off point for the charging circuit. Because the battery will be stored in the
generator for a long period of time a float stage will also be beneficial to the charging
circuit to combat the self-depletion of the battery. This will allow the battery to be stored
close to full capacity and will be beneficial squeezing as much life out of the battery as
possible until it will need to be replaced. The charging circuit will also call for an
equalization stage in the process where a current of two amps was applied to the
battery for an hour in order to equalize all batter cells in the specified battery.