Re hologram, IIRC Nokia said it took 3 days until the hologram was copied with such accuracy that their own people couldn't tell the difference...

That said, the Nokia logo is like a pretty tall button, and has round circles on the sides. In the photo I don't see that detail.

it's in the mail

I bought a BL-5J clone for US$3.72 each delivered.
http://www.dealextreme.com/details.d...691~r.60561251

Capacity is limited, but for the price it makes a good emergency backup.
I got less than 12 hours, including overnight, before it died with little warning. Maybe an hour of music, a little web. Its such a power-hungry phone, that you need as much battery capacity as you can get.
The cell is protected, and it even has a real hologram, but not as nice as the true nokia one.

(disclosure: referall code gives me 1c/battery:-)

Good news: I have my N900, and the cheap eBay batteries work. They are, as expected, worth exactly as much as I paid for them.

I'll post lshal results and use observations in the next day or two. For now, know that they report a design capacity of ~600 mAh. They hold this charge exceptionally well - after 5 hours of heavy use, still 100% charge. Can't beat that kind of staying power!

Summary: these work, but have less capacity than the OEM and have non-functional onboard controllers, so state of charge (SoC) and voltage are not correctly reported to the N900. For emergency/backup use, I'm fine with this, but I won't be using them under normal circumstances.

Has anyone else purchased cheap batteries that correctly report SoC?

Another HK/China seller, focalprice, has BL-5Js, but these are after-market branded, not fake Nokia, and have some packaging.
They are about us$6 each shipped, and _claim_ around 1000mAHr.

http://www.focalprice.com/MB097B/37V...L5J_Black.html
http://www.focalprice.com/MB105S/37V...okia_5800.html

Not much more to add on my eBay batteries. They are somewhere in the 400-500 mAh range and fail to report SoC, so they're useless as anything but emergency backups.

For $10, I now have an external battery charger and two emergency batteries. Well worth it!

Now to get a spare battery...

Dealextreme are now listing "100% Genuine" BL-5J for us$17 delivered. At that price it must be real!

guys, would a 1800 mAh capacity batter harm our N900 in anyway?
my place here sells BL 5J with 1800 mAh capacity.
the brand is called Sun Global.

Even if the stated capacity was true (it is not), it would do no harm.
Unless it exploded for being dangerously engineered to get that otherwise impossible capacity in that volume.

Are you sure it is not true? I purchased "big" replacement batteries on Ebay before and, though maybe the capacity does not match the labeling, it is still way better than original batteries (say,original BLB-2 is 700mAh, if you buy one marked "1200", you may get 1000-1100 or so). The question is how do i pick good ones? Any advices? I want bigger battery for my n900..