I have an easun power inverter 3K 24VDC, 120VAC, the problem that I have is that it does not work very well, when I am charging with salar panel it never charges 100% even though I have 4 solar panels of 265w, when I charge it with a single bank of batteries, with utility loads 100%, but when I remove the utility it tells me that it lacks load, I want to know if I have to do an update to the firmware