I use the Goal Zero Nomad 7 with a big Anker 26,800mah battery pack. In all honesty, the Anker will charge my iphone 5 or 6 times on its own, so its probably overkill. But the Nomad out all day will replenish the Anker enough that at the end of a 7 day hunt theres still some juice in the Anker. If Im going for shorter 3, maybe even 5 day hunts, I will just take the battery, and just be conservative with things. it helps that most places Im at, there is no signal, so I am not tempted to jump on Rokslide or watch Youtube videos hahah
I dont think that Nomad 7 will put a full charge on the Anker though, but again, it keeps it "topped off" for the most part