600 VA Battery inverter. Anusolar sells these as solar "power generators" but what they deliver is a battery inverter and a separate PWM constant current charge controller. The inverter is loud!

Connected the inverter to one fully charged 100AH battery and it provided only about 0.4 units -a fan and a tv for a couple of hours before the battery was discharged - didn't record battery DoD. I can't imagine it's very efficient with all that energy being lost to noise - idle consumption is a massive 7W !!

Tightened the battery connections (DC connections need to be very tight to function properly) and the performance improved but not significantly. The inverter is able to invert only 0.5 - 0.6 Kwh from a fully charged 12V 100Ah battery. Either the battery is not functioning to spec or the inverter is very inefficient. The battery should be able to store 1.2Kwh (12V x 100Ah) so assuming that it discharges to 75% there should be 0.9Kwh available per cycle. But as there's only 0.6Kwh consumed by the load (a computer, modem and router) over 12 hours, the inverter is only ~70% efficient!