Strider - Define "bunch of current"... ?
I recently acquired the same inverter... There's a sleep mode that's disabled by default whenever the 12V source is disconnected/reconnected. Not sure if this is what you're seeing. And yes, there's quite a "pop" when you first complete the 12V side when the caps inside draw their initial charge.
To enable/disable sleep, turn the inverter on, watch the display, and when it says something to the effect of "power save disabled", turn it off for about 3 seconds, then back on. The display should now say it's enabled when it goes by.
After a few seconds with extremely low or no load, it should enter a sleep state, drawing only a couple of watts. It sends out "feeler pulses" every couple of seconds, and if there's a sufficient load there, it powers up to feed it.
The no-load draw without the sleep mode engaged is in the 20W range (ammeter on the display on mine teeters on the edge between 1 and 2A). In sleep mode its something like 100mA. Also, the at-a-glance giveaway that its snoozing is the backlight for the display turns off (the display itself still has info on it).
As for operating life expectancy, jury is still out on mine and probably will be for a while... It's not quite in service yet, waiting on other things. I've done some basic testing and that's it.
Hope that helps....