This looks like a nice solution for extra power but it is a bit pricey. I have a 450w power supply that cost around $220 in 2005. It's been very reliable for running the CPAP for a couple of nights between charges.
Plus on this one is the smaller size and weight
with about the same power. Also the USB sockets.
Minus is the higher cost.
1970 Trails West Campster
2008 Honda Ridgeline