I have a similar unit, but at 300W it wont do much, just about an old laptop, as chuck said you wont get a DVR and a lap top from it.
I've got a
solar panel feeding a car battery and then i
invert it, it does not do much TBH, a little generator set like they have on
construction sites would be great, I dont know what voltage they use on site in the US here we use 220Vac but on sites it is 110Vac for safety, so you'd pick up a 110Vac generator on the cheap, but the Honda ones are very good if you were looking into them