Watts per day (considering voltage & amperage) is an important calculation, for me. I use watt hours and determine the daily average. When determining how long my battery bank could power which items and for how long in the absence of my charging methods, it was crucial. Assuming that anyone building such a system is familiar enough with electricity knowing that a watt is a joule/second and has the ability to determine kw*hr.
Sure, the panels put out 96VDC @ 2A. I read that as 8 amps. One hour of that is 192 AH (less line loss and conversion loss) into the batts, since everything relies on the batteries.
Watts are derivative. If I have to do something like that I prefer to use KVA.
That has worked for me on large and small systems. I've got some small stand-alone systems fielded now that have done great for 2 years with minimal mainenance except PM.
/johnny
Watts are a measure of the rate of energy consumption. Watts are how much energy you are using RIGHT NOW. If you use a watt for an hour, you have used a watt-hour. Maybe you have calculated how many watt-hours you use per day. But you can’t possibly calculate how many watts you use per day.