To better understand the dynamics of using my hot water tank as a energy storage load, I turned it off overnight, so I could see how much power it took to get it back to the setpoint.
The heaters were turned off yesterday when the sun went down, and turned back on 15 hours later. It took a bit over 4KWH to recover energy lost. This was with minimal hot water use.
Since this was also the first big load that was run through the new transfer relays. I got out the thermal camera to see what was warming up. Looks like reasonable temperatures. The electric range is the next big load I will move over. Am looking at the best construction method for the high current solid state relays current sensing system. Luckily I only need to make 8 of them.