Fair enough, you don’t think you need much more battery capacity. And you seem pretty sure of it.
But, to the point, your thinking is flawed.
It makes no sense to spend ALOT of money to get a little more battery capacity, when there are so many options to spend less money to get ALOT more power.
Sure maybe you can recoup some by selling your used Battleborns. I’m just not aware of a market for used batteries. But heck, put them on Craigslist for however much will make it worthwhile to you. If someone wants ‘em, they take 5 minutes to disconnect and remove.