I just acquired one of these Power Packs off fraz after doing a bit of research on different set ups. A dual battery kit isn't ideal for me as I'm always in and out of different vehicles. Having a portable power source also allows me to leave the fridge and wife at the campsite when I go fishing with the guys
The only issue I have with the ARK Power Pack is the charger output. It's only 1.5amps which is very slow. Going off figures on navara.asia, that means a half-discharged 130Ah battery would work out at 65/1.5 = 43 hours to recharge (at a minimum, it will actually take longer). Alright for at home but useless on the road.
If your battery will not run for the entire trip, you need to set up another charging system like solar panels or off the alternator.
The top of the range ARK PAK is apparently very noisey to the point where people say you can't travel in the car with it.