What Sol Donum™ Vulcan Energy Systems Can Power

How Storage Capacity Is Measured

The output of the AC generator and the battery capacities are noted by the amount of energy they can provide over the period of one hour (thousand watt hours KWH). Thus, a 4KWH (4000 watt hour) system configuration means that the battery stores enough energy to run a 4000 watt load for 1 hour. However, the cost to generate AC energy from that 4KWH battery is 8.5% of the system energy. This means the system is 91.5% efficient.

Refrigerator Example

For a 21 cu. ft. Energy Star refrigerator that uses an average of 71 watts every hour, the formula to derive the number of hours that the 4KWH system can run the refrigerator until the battery is depleted is:

1. Total hours of operation = 4000/71 for a total of 56.3 hours
2. Multiply total hours by 91.5%
3. Actual runtime hours = 56.3 * 0.915 for a total of 51.55 hours

This formula can be used to calculate the real number of hours that a system configuration can run any one or multiple series of appliances: (System size/total watts of appliances) * 0.915

Here is a sampling chart of several Vulcan configurations and the various durations that each appliance can run, based upon the Silicon Valley Power energy use chart from 11/25/2019.