Howdy from Austin.
The Danhard is louder outside than I expected it to be. There are two fans blowing outside.
Inside the noise is there, but I am not sure how to describe it. It is not so loud as to cause any problems with sleeping if that helps. We have had the AC on most of the nights we have used it so far.
I have not measured the maximum time that the Danhard will run via battery, but on two different occasions we have used it for extended periods of time. The first was the day we picked it up, and we used it for an hour. The second time was at the NCAA Baseball tournament, and we used it for multiple hours multiple times over a single evening and night; this was when we found that the original inverter (Xantrex RS2000) was not working well with the Danhard and Honda 2000. We had to use the Honda to recharge the batteries a couple of times to keep the AC running.
The Honda 2000 works well with the Danhard as long as you also throw the appropriate inverter into the mix. We have found that the Xantrex Prosine 2.0 works perfectly.
The inverter provides the smarts to recognize that when the AC first kicks on that it needs more amps than the Honda can provide, so it power-shares and provides a few amps from the batteries for just a few seconds. Then it realizes it does not need to provide those amps and lets the generator shoulder the load for running the AC. When it is set correctly the gen also provides charging for the batteries, a little when the AC is running and more when the AC has cycled off.
The Danhard does an excellent job of cooling. If you have not heard we in Central Texas are having a record setting hot summer with 42+ days over 100 degrees when we normally only have 12 all year. We have been able to drive the temp down into the low 70s in the middle of the afternoon of hot days when testing things. In other words it cools far more than I think we could ever need (knock on wood).
Hope that helps....
Greg in Austin
2008 Ford 6.0PSD EB/E-PH SMB 4X4 Aluminess f/r bumpers (13.5mpg avg, 15mpg hwy) 52k miles [Texas McBeast]
2006 Toyota Prius (48 to 68 mpg) 120k miles [Penelope]
2013 Jeep Wrangler Unlimited Rubicon (15 to 18 mpg) [Johnnie]
2012 Mitsubishi MiEV (no gas required) ($.50/day in electricity) [Evie]