1. Selection of the alternator type, either 8000 or 6200. Our 8000 series is the popular choice for telecommunications and battery charging applications. The 6200 is used for specialized military applications requiring ultra fast voltage regulation and fixed engine speed operation. Details on the 8000 series alternator can be found here.
2. Selection of the generators power range on applications that incorporate cycle charging (using a combination of battery and generator to power the load) the selection of the generator’s power range (kW or Amps) is determined by:
Factoring the daily or weekly energy demand of the load (kWh or Ah) against the desired generator run time. For example a simple calculation: The load is 1.5 kW over a 24 hour period, the daily energy demand is 36 kWh. If you wanted to run the generator for 3 hours a day you would run the generator at 12 kW. This is a simple calculation as it assumes the battery is 100% efficient.
The battery bank size and technology will also affect the generator run time. If the battery bank is not able to charge at 12 kW per hour then the generator will have to run for longer period at a lower charge rate. The generator will also have to run longer to offset the battery charging losses (inefficiencies).
Do not oversize the battery bank with the goal of running in the engine only a few hours a week / month.
3. Selection of the generators power range on solar/wind hybrid applications is similar to paragraph 2.
The amount of solar and wind energy produced is subtracted from the load’s energy requirement. For example a 2 peak kW array at the site with strong sun can produce 10 kWh. Using the same 1.5 kW load over 24 period, we subtract the 10 kWh produced by the solar from 36 kWh requiring the generator provide the energy deficit of 26 kWh. therefore a 12 kW generator would run for 2.2 hours (not factoring in battery inefficiency).
Due to the present low cost of solar photovoltaic modules the size of the solar array is typically determined by either meeting 90% of load energy needs or the space limitations of the site.
It’s also important to note that the generator in hybrid applications should have sufficient capacity to run the site in the event the solar fails due to theft, charge controller or battery failure.