Kelly has an old Casio Brigade phone, but it can't hold a charge anymore, so he got a new Samsung Galaxy S5. But when he's out in survival training, he isn't much of a fan of the battery life. Leo says that the battery life isn't all that great, but the good news is that he can swap out the battery. He should buy a bunch of spare batteries and then he can swap them out in the field. And he can even buy a solar charger and charge them up when not using them.
He can also get the Anker 7500 mAh extended battery case. There's also the Jackery External battery charger that has up to a 10,000 mAh battery and can charge up to 2 devices at a time.