I picked up a portable 5v 3A power supply (uses and charges 4 18650s) with a USB out that runs great. Charges faster than my trustfire charger and at 12,000mah it doesn't require constant charging.
In other words... I can take my passthrough where ever I go. Now, it's only rated at 3A but so far, so good.
I'll upload a pic later if anyone wants to check it out.