[lurkingknight]

if you would double up 2 of those tubes with a parallel harness you'd effectively double the life and discharge of it, so yes, it would work better. Don't put them in series. The problem with that is the parallel harness will eat up some precious buffer tube space. It's a pain in the ass to get everything to sit well, especially if you add a mosfet into that mix... which you should, because it's going to be hard on trigger contacts.

I'd go with a full stock or brick in an external battery though, something in a mag pouch on the stock. not everyone likes this setup though.

For my mp5 I havea 7.4 30C 4200mah battery only driving a lonex A1 on 16:1s, but I know I don't have to change the battery in that gun during a game. The full stock gives you those kinds of advantages, but might not be so stylish on a shorter m4.

My g36 runs on a lonex A1 with 13:1s and the batteries I use are nanttech 11.1 20-35C 1600mah, bricks those are as big as I can fit in a g36C handguard, and a couple of them have gotten puffy. Not bloated, but puffy. So I figure I'm riding a threshold right there. Any mechanical jam, hiccup or failure that the triggermaster fet doesn't catch, it will probably damage the pack. There I don't have much of a choice. It's too bad I can't get packs that are that width and height, but longer length for more mah.

The ones that have gotten puffy I pull out of main service and use them on the test bench so I have quick access to them. For 12-13$ a pack, it's not worth fucking around with them and causing a fire, I just get new ones when I need them.