AC 200 MAX less 2% despite loading

if I connect the AC200 MAX to the solar panel in the morning and charge 10 to 30 watts, I still lose 2%.

Over what period of time did you notice the 2% drop? The AC200Max is not a small power station and internally uses power just to stay on. Your 10-30 watts of solar input is too small to offset the internal power consumption and you’d need to get more or larger panels.

That is because your AC200 Max consumes more wattage just being turned on than the wattage you are feeding it.