I finally managed to get ess working, but in a bit confused as to why my battery monitor is showing a lot more power usage than my loads. Any ideas where the extra power is going? How accurate is the monitor? 
asked
Extra power drain from batteries
Thanks I'm beginning to understand all this now.
Devices use power. DC/AC conversion has 10-20-% loss. Many, many. many topics on this subject.
That’s before you consider reading errors at low power.
Welcome to the world of physics.
But this figure is around a 30% loss and the multiplus is said to be over 90% efficient.
The battery power is going straight to the multiplus and fed to the loads. Grid feed looks to be zero because my utility meter hasn't moved since starting the system up around 3 hours ago.
The inverter has an efficiency curve at some levels it is less efficient. But also are your batteries good as conversion (what is their efficiency) and then is your cabling warm? Also inefficiency.
Any device drawing power in the system is self consumption.
Then your loads might have a poor power factor. Especially led lighting. Says 7w but draws 14w.
Your net load is 28W TO the grid and 355W in loads. That's 383W total off 463W from battery. That is net 17%.
At low Wattages the readings are also a bit inaccurate. readings also may not perfectly align with the exact same point in time.
At such low output, the idle load powering all the devices is also a high percentage of the total output.
If you worked on, for example, 50W being used to power all the devices, that is more than 10% of your total battery draw. At 5000W it is 1%.
Trying to draw conclusions on efficiency at low power, and without understanding the load power factor, is mostly pointless.
All normal, discussed here numerous times. Have a search and you will find other queries like this.
