I don't think that's how those units work. A watt is a measure of energy/second (1 joule/second). It needs to be multiplied by a time to get a measure of ener

I don't think that's how those units work. A watt is a measure of energy/second (1 joule/second). It needs to be multiplied by a time to get a measure of energy. 23WH/day is also unbelievably low. A Chromecast draws 24WH/day just idling. Given the grow lights, 550W probably is the power consumption. It would depend on how long the lights run per day, but an 8 hour on cycle would be 4.4kWH/day plus whatever it consumes without the lights for the other 16 hours (presumably a much smaller amount).