[rawr]

Not Pentax, but related - with Sony lithium batteries the most apparent difference between genuine batteries (bought off the Sony site) and 'genuine' Sony batteries bought off eBay was that the 100% genuine Sony battery weighed noticeably more than the fake battery (and the original lasted longer too). Packaging, labels etc however looked identical.

[glanglois]

I know many here would use third-party batteries without question but I would never use a fake. That's a whole different issue. Counterfeiting must be discouraged and, in a practical vein, I wouldn't know what else they're lying/cheating about.

But before we get excited, the email to Pentax is the correct next step. It will answer the question of authenticity and will alert Pentax if the seller is flogging counterfeits. The seller needs to be spanked in that case.

[Schraubstock]

So, buying older batteries off the shelf means they will have a shorter useful life.

And that is the reason why this battery has a prominent date label on it. (201010) These batteries start to deteriorate the moment they come off the production line. Makes no difference whether they are being used or just sit on the shelf. When people purchase cheap third party batteries and complain that they are not so good, it is usually a case where a dealer wants to offload old stock. They may already be half way through their life expectancy. The prominent date label is an attempt to circumvent this. And it has nothing to do with quality.

Greetings