Minus by percentage

I am useing an efergy monitor to upload my solar generation. The clamps are reading about 13% more production then my inverter is reading . What is the rule to minus 13% ?.

Try -

power -= power * 0.13

champion thank you :slight_smile:

Gordo… - do your clamps read a consistent 13% more than the inverter? And, what output does efergy show at night time?