G'day & Welcome Ruk58.
The ArkPak is lovely, an all-in-one solution, but I reckon I can give you the components and most of the functionality for half the cost, and simple enough that most folks could assemble the same capabilty.
Here is what the latest ArkPak does:
Built-in 6 amp, 7 stage smart charger
Built-in 150 watt inverter & 240V socket
2 x 10 amp 12V accessory ports
1 x 50 amp Anderson Plug
1 x 5V USB Port
Isolator Switch
2 x Protected external high current terminals
Time tracker technology with LCD Screen
Strong easy carry handle
Suits all 4 main battery types
Suits batteries up to 130ah in size
OK, let's start with a box for the battery, this one by
Projecta has most of the bits on it. $89
Then a quality
smart charger by CTEK, $90 first item.
Next, an
inverter, 150W is nothing these days, will run a laptop and charge camera batteries but won't run appliances. This is a cheapie, but includes the 5V USB outlet as well. $12
Some
Anderson plugs, $20
Maybe you need some wire and few other bits, cigarette sockets, $50 tops. Still all up less than $250! which pays for your battery.