User Guide
Off-Grid Solar Energy Storage
Vulcan may operate using solar panels only to store energy to power AC electrical loads.
Depending upon the average AC load measured in watts, a Vulcan system, when combined with
adequately sized solar panels that are properly placed and receive the recommended amount of
sunlight for storage and load support, can run AC loads perpetually over the lifespan of the
Vulcan Inverter-Charger and combined Energy Stores.
1. Determine the 24 hour load requirement = (total load watts * 24)*(inverter efficiency of
0.92) this is the minimum amount of storage required by the Vulcan system. For
example, an average AC load of 250W = 6kWh of energy use over 24 hours. Vulcan
would need a minimum storage capacity of 6.5kWh to carry the load fully for 24 hours
since it is 92% efficient.
2. Determine the solar irradiation period of your location in hours. Maps can be found at
the National Renewable Energy Laboratory website . These are the average
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representative number of hours that solar panels in any specific region of the Earth can
harvest their maximum energy, given ideal conditions. It is recommended that you size
your panels appropriately to store 24 hours of energy and run your AC electrical loads
over the optimal irradiation time window. With the above example and a winter
irradiation period of 4.5 hours, it is recommended that the panels be sized at ((AvLoad *
4.5) + 6000)/4.5) or 1,583W.
Figure 7.
, illustrates a schematic recommendation for an off-grid Vulcan system with power tied
into a circuit breaker protected distribution panel. Using one (1) Inverter-Charger and two (2)
Energy Stores, the illustrated system in
Figure 7.
will adequately power the example listed
above.
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https://www.nrel.gov/gis/solar-resource-maps.html
Battery Energy Storage and Power Solutions
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