I either use ratchet straps or bungee cords. No reason to get too fancy IMO
That being said you can always shorten a bungee with another knot to make them fit perfectly between the two totes.
Depends on how much draw it has too, do you how many amps it pulls when on?
I run my IndelB on a goal zero battery pack next to the fridge. I have the goal zero being charged from the 12V in the cargo area when the vehicle is on.
