Hello: I want to plug in a 100 watt lamp to my inverter to see how long my batteries last. I am testing two 12 volt marine batteries (27dc2) to determine if they are good enough to keep. I connected them in series to my AIMS 24 volt Inverter (https://www.aimscorp.net/2000-Watt-Pure-Sine-Inverter-Charger.html). Now that I charged them to "full capacity" (the green light is on Float Charge), I want to know what power they really have. I used it run my house and it lasted only 2 hours and 40 minutes. I estimate I run a max of 200 watts an hour. That would tell me the batteries are not holding the charge if you figure those two batteries should have 1200 watts. MY QUESTION IS: how do I plug it in? I plugged into the GFI outlets on the side of the inverter but the lamp does not come on. Thanks!