Short answer: Sony’s NP-FW50 and the YO TNP-FW50 are not “genuine versus counterfeit” — they are products from two different brands. The quickest way to tell them apart is the USB-C port: the TNP-FW50 has a direct charging port built into the pack, and the NP-FW50 does not. Next come shell shape, contact finish and printed markings. Run those three comparisons and you will not mistake one for the other. The type that genuinely deserves caution is a third category: a blank-shell pack with no brand marking, no Sony marking, and “NP-FW50” printed on it.
This is worth a dedicated article because two misunderstandings keep appearing on the used market: a third-party direct-charge pack sold as if it were OEM, and the reverse, a legitimate third-party pack returned as a fake. Neither is necessary once you know what to look at.
Positions first: one OEM, one direct-charge replacement
Sony’s NP-FW50 is the original part for this battery system, rated 1020mAh / 7.7Wh / 7.2V — towards the small end of the range — and it fits earlier A7 bodies, the A6000/A6300/A6400, the A5100, the NEX series, the RX10 and the ZV-E10.
The YO TNP-FW50 is a replacement built to the same specification, with the same rated voltage and capacity, plus a USB-C port integrated into the shell so it can be topped up from a charger without a dock. That is a difference in design intent, not a shortcut in manufacturing — adding a port means another shell tool and a different circuit layout.
One common error worth ruling out: the A6600 uses NP-FZ100 and is not part of the FW50 family. Any bundle pairing an A6600 with an FW50 pack, whatever the brand, tells you the seller does not know the product.
Appearance: three differences you can see at a glance
| What to look at | OEM NP-FW50 | TNP-FW50 (direct charge) |
|---|---|---|
| USB-C port | None, only the contacts on the base | A USB-C socket on the side or end, for direct charging |
| Shell surface | Fine matte texture, rounded corners | Mostly matte, with an opening and reinforced edge at the port |
| Marking position | Large printed model and capacity on the face | Brand and model on the face, capacity details on the rear label |
| Thickness in hand | Fits the bay closely, comes out with a slight suction feel | Slightly thicker on some batches because of the charging circuit; check it seats fully |
The “slightly thicker” in the last row is not a defect but a consequence of the structure. Checking whether it is seated is easy: with the pack in, the battery door should close naturally without pressure. If it needs force, either the pack is not fully home or the dimensions are wrong — do not force the door.
Another detail that gets missed: under bright light the face printing on an OEM pack shows a fine dot texture with clean character edges. Counterfeit printing tends to be heavier with feathered edges and rubs off under a fingernail. That check applies to both types and is a general way of judging whether something came off a proper line.
Contacts, latch and markings: details beat appearance
Turn the pack over and look at the base. The FW50 is a four-contact design, and the contacts should be flat metal pads with an even metallic sheen, edges neither chamfered nor darkened. On a genuine part the spring contacts return crisply, with a clear detent when pressed.
The TNP-FW50 places its contacts in the same position as the original, which is the precondition for compatibility. The difference is in the plating: proper products are an even pale gold or silver-white, while poor ones show dull patches, blistering, or even the base metal showing through.
The latch is another checkpoint. The recesses on both sides should have clean edges without burrs, and fitting the pack into a body should produce one light, crisp click. If it goes in loosely and only powers up when you wiggle it, the tooling tolerance is poor, and such a pack is prone to cutting out under vibration even if it charges.
These are all observable differences in appearance and feel; none requires opening the pack. Any advice to “take it apart and check the cell brand” is not actionable for an ordinary user, and opening one is not recommended — once a lithium pack’s shell is breached, the risk far outweighs the benefit.
Markings and labels are worth reading too, and the way capacity is written should be consistent. The electrical ratings should read the same on both: 7.2V, 1020mAh, 7.7Wh. Those three figures define the NP-FW50, and no legitimate replacement should change them. If you see an FW50 labeled “2000mAh”, that is almost certainly inflated — it is not achievable at this volume.
The difference lies in the brand and model: the original carries SONY and NP-FW50 along with country of origin and a serial number; a replacement carries its own brand and the TNP-FW50 model, with the serial usually on the rear label. Either way the serial should be unique and traceable, and a repeated number is a clear anomaly.
Certification marks are worth a glance as well. Proper products carry the relevant safety marks, with crisp characters in orderly positions. Blurred marks, misregistered overprinting or missing strokes usually mean it did not come off a proper line.
Five checks, in order, for a used purchase
- Is there a USB-C port? If there is, it is a direct-charge pack like the TNP-FW50. If the seller calls it OEM, end the transaction.
- Read the face printing. Confirm that brand and model are consistent with each other: a TNP-FW50 will not say SONY, and the reverse holds too.
- Check the three ratings. 7.2V / 1020mAh / 7.7Wh — if the numbers do not agree, it is inflated or it is not an FW50 at all.
- Turn it over and inspect contacts and latch. Darkening, blistering or burrs — any one of them is a reason to walk away.
- Ask about its history. How many cycles, any swelling, any water exposure. Vague answers mean negotiate hard or do not buy.
One practical addition: if you were planning to buy a third-party direct-charge pack anyway, there is no reason to hunt for OEM on the used market. New prices for these packs usually sit at the budget end of the market, which is a better bet than gambling on an old pack of unknown origin. Body fit notes are on the TNP-FW50 category page, and general specifications are in the NP-FW50 series.
FAQ
I received a pack printed with a third-party brand — was I swapped a fake?
No. A direct-charge pack like this is an independent compatible product with its own brand and model, and it should not carry a Sony mark. As long as the ratings and contact layout match, it is a normal product.
Will a TNP-FW50 damage the camera?
Voltage and contacts follow the NP-FW50 specification, so normal use will not damage the body. The risk comes from poor products that omit protection circuitry, which is why contact finish and certification marks matter more than price alone.
How can I quickly tell whether an FW50’s capacity is inflated?
Look at how capacity is written. At this volume 1020mAh is the sensible ceiling for the format, and anything claiming 1800mAh or more is not credible. You can also shoot a full run and compare the frame count against a pack you know is sound.
Are the A6400 and A6600 batteries interchangeable?
No. The A6400 takes NP-FW50 and the A6600 takes NP-FZ100, and the bays differ in size. Check against the specific body model rather than reasoning from “Alpha 6000 series” as a group.