User Guide
Considerations for Extending Vulcan Battery Capacity
When mapping out your Vulcan system and the amount of battery capacity required to meet
your needs, consider the job that the Vulcan system must accomplish (amount of continuous
output power) and the number of hours that your equipment is required to run. Those are the
primary considerations for initially sizing, adding more battery capacity and the type of Energy
Store(s) to consider.
Battery Runtime Calculations
When running on battery power, the Vulcan Inverter-Charger uses a small amount of battery
energy to convert DC voltage to an AC voltage sine wave. The energy cost is 8% - 8.5% of the
battery energy used for the power conversion. This is used to calculate the number of hours the
Vulcan system can run loads from its AC voltage output.
EXAMPLE
: A 21 cu. ft. Energy Star refrigerator uses an average of 71 watts every hour
(71Wh or 0.071kWh). The formula to derive the number of hours that a 5kWh Vulcan
system can run the refrigerator until the battery is depleted is:
1. Divide the Vulcan system capacity (5kWh) by the load watts = 5000/71 = 70.4
hours
2. Multiply total hours (70.4) by the lowest Vulcan efficiency of 92% (100% - 8%)
3. Actual runtime hours = 70.4 * 0.92 for a total of 64.7 hours
This formula can be used to calculate the number of hours that a Vulcan configuration can run
devices plugged into its AC voltage output: (system size/total watts of load) * 0.92
Battery Energy Storage and Power Solutions
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