What the port actually is
Inside the bag there is a female USB socket on a short lead. Outside, usually on the shoulder strap or the side panel, there is a male port. You put your power bank in the internal pocket, plug it into the internal socket, and then charge your phone from the external port with your own cable.
Three practical consequences follow, and every one of them is something buyers get wrong:
- You still need to buy a power bank.The bag supplies no power. A 10,000 mAh bank is the sweet spot for travel — roughly 37 Wh, comfortably under every airline threshold.
- You still need your own cable on the outside. The pass-through carries current from the bank to the port; it does not terminate in a connector for your phone.
- It is USB-A, and it is slow. These are almost always legacy USB-A pass-throughs with no fast-charge negotiation. Expect trickle charging, not the speed you get plugged into a wall.
The battery rules that actually govern this
Because the power is a loose lithium battery, the rules that matter are the ones about spare batteries, and they are strict and non-negotiable: power banks fly in the cabin and are prohibited in checked baggage. The FAA allows batteries up to 100 Wh with no approval, 101–160 Wh with airline approval and a limit of two spares, and forbids anything above 160 Wh outright.
The conversion you need is one line: watt-hours = (mAh ÷ 1,000) × 3.7. So a 10,000 mAh bank is about 37 Wh and a 20,000 mAh bank about 74 Wh — both fine. Anything above roughly 27,000 mAh is over the 100 Wh line and becomes a conversation at a gate. The full version, including what to do if your bag gets gate-checked with a bank inside it, is in power banks & lithium batteries on planes.
One more consequence specific to these bags: several airlines have recently added their own rules about using or charging power banks in flight. Because those are carrier-specific and changing, check your airline’s own page rather than assuming the strap port is fair game at 35,000 feet.
Why the good travel-pack brands skip it
Osprey, Cotopaxi, Eagle Creek and Pacsafe do not put USB pass-throughs on their travel packs. That is not an oversight, and it is worth understanding before you weight this feature heavily.
It is a hole in the bag. Any external port is a place water gets in and a place a panel has to be reinforced. On a pack sold on weather resistance that is a real cost for a small convenience.
It is the first thing to break.A soldered socket on a flexible shoulder strap is a hinge point with electronics in it. When it fails — and it is the most commonly reported failure on bags that have it — you have a dead port sewn into a bag you otherwise like.
A cable does the same job. Run your own short cable from the bank in an internal pocket out through a zip gap. It costs nothing, cannot break the bag, works with fast charging, and works on every bag you will ever own.
That last point is the honest verdict on this whole category: the feature is fine, and the workaround is free. Buy one of these bags because it is a good cheap personal item — which the MATEIN genuinely is — and treat the port as a bonus.
What to look for if you do want it
- Port placement on the strap or the upper side panel. A port at the bottom of the bag means the cable runs down your body and catches on things.
- A dedicated internal battery pocketwith an elastic retainer, so the bank is not loose against a laptop. Loose spare batteries against metal is precisely the short-circuit scenario the FAA’s terminal-protection rule exists to prevent.
- A cover or flap over the external port. An uncovered socket collects lint, rain and grit, and grit is what kills it.
- Everything you would want in the bag anyway— a padded laptop sleeve, a luggage trolley sleeve, and dimensions that let it fly as a personal item. Check those against your airline’s numbers before the port enters the decision at all.
A note on “anti-theft” on these bags
All three picks are marketed as anti-theft, and on this class of bag that word means a concealed pocket against your back and nothing more. It is genuinely useful against a casual hand in a crowd; it is not slash-resistant mesh or locking zippers. We rank the tiers honestly in our anti-theft travel backpacks roundup, and the pattern is the same as the USB port: a real small feature, oversold.
