The lipos you linked are not really good for mountain boarding. You can either go with the recommendation on the trampa side or get some hk graphens or heavy duty 60C. You look up the size of the lipos in the specs on hobbyking.
There is also an opportunity to get a LiIon pack made or make by your own which will fit in this box. @taz made a nice 12s7p for his trampa box.
If you don’t know how to build LiIon packs and don’t have anybody to build you one than lipos are your way to go. As i said have a look at hobbyking graphens one Heavy Duty packs. Get high C rated pack, 45-75C is a good range. You will not regret paying a bit more for them.
One, I will parallel charge two at a time. I need to make a pig tail for my other charger so I can charge faster though. I’ve been using this charger for about 3 years though for my quads, and my newer one is much better lol
For general use, I prefer the li-ion pack.
Bigger range, easier charging, less finicky with storage charge status.
If I want, I can put in some 5Ah lipos I have to make the board lighter for jumping.
However, I have gotten used to the weight and I can get quite a bit of air now even with the li-ion pack.
I have not weighed the pack but my guess is 48grx12x7 + nickel + BMS + wires + heatshrink = approx 5kg
I did not have very good results with the Trampa motors. They lacked power and overheated easily. However one of them was defective so it could be due to that.
Keep in mind that my terrain is demanding.