I’ve was measuring the overhead of the EP500 in UPS mode and put a Kill-a-watt on both the A/C wall plug and the EP500 plug feeding my entertainment center.
The readings are identical, though that may not be the whole story. The battery level slowly creeps down and the system occasionally powers up the 560w charging circuit to keep the battery at 100%. I’d speculate that the onboard logic is powered off the battery so there’s an extra load there that’s hard to measure (I’ll have to do a longer test over a day or two and compare the total power used - I guess I could do that w/o an A/C load and just measure the power pulled from the grid).
The A/C Load watts measured on the unit appear high. With the Kill-a-watt showing 67 watts the BP500 is reading 105w for the AC load (I tried two different meters). That seems like a pretty significant discrepancy. Has anyone else looked at this? I need to check some higher loads and see if the error is fixed (38 watts) or a %.
I also did some power loss tests in Standard UPS “Off Line” Mode. Seemed to work fine (for my TV and some other components). I put a scope on the output power lines and I saw about 25ms to switchover (close enough to the spec).