This thread is somewhat old, but in case you haven't actually bought one yet, DON'T! Charging is very erratic! Sometimes it would charge, sometimes it would not. For example: Sometimes my Air Venturi Avenger is at 3000 PSI already, but I want it to be full (all the way to 4,350 PSI), it would go to 2500 PSI and just hangs there. It would not go past that. Then you turn it off and restart the charging. Sometimes it would go all the way to 3000 PSI, then hangs there. I would not go past that. I have to try many times, relieve the valve, restart. Same result. Hangs at random PSI, sometimes 2000PSI, sometimes 2500PSI, sometimes 3000PSI. After countless tries, then on pure luck, you get it to charge to 4350 PSI (max on the Avenger). My head has become bald since owning this POS. Maybe it's just mine. I'm past the warranty period, so I can't do anything except keep trying. I drain it properly. I oil it properly. Many times, I've thought of throwing it out the window of the second floor. I'm thinking of trying out the Air Venturi Nomad II. Maybe I will have better luck with that one.
Luck is exactly what you'll need. Do a search on this forum for Nomad threads.
12V compressors have terrible reliability long term. Some guys keep trying different brands and hope they are the lucky one that gets the rare 12V compressor that lasts. They end up spending a dime to save a nickel. Hatsan Spark, Nomad II, GX2, GX3,Vevor,etc.,etc. are all minimally designed, hard to repair, hard to get parts, and repeatedly fail in a few hours. They are cheap for a reason. Add up the cost of all these soon to be boat anchors and the repeat buyer spends more than he would have for a compressor that isn't doomed to failure. 4500 psi puts tremendous strain on a compressor. The metallurgy and design of these compressors just doesn't hold up for very long under the stress.
There's a reason a Daystate costs more than a Xisico and there's a reason a Coltri costs more than a Nomad.
P.T. Barnum said it best.