Hello

The 18650 is a great idea. Could the layer currently holding the battery and adding several mm be removed to help the 18650 fit? Then, while redesigning the backcover, 2 or 3 of them should fit without adding thickness to the mugen style cover.

IIRC, the idea is to make the N900 "long term" ie robust and less dependant on stuff than can only be purchased for a month on aliexpress like scuds, or openpandora batteries.

18650 wide availability is also a great plus -I remember "repairing" vaio batteries with a stack of 18650 purchased from ebay in 2004 or 2005.

IMHO there might be n900 parts long after openpandora becomes a rarity - if only because much more n900 where sold worldwide. And 18650 will certainly be available after other n900 parts start to fail (flash?) :-)

So going with the standard 18650 seems the way to go - but only if it doesn't cause Estel too much trouble or delays in the backcover redesign.

Any news about the barrel connector??

Considering the issues with the 5v/GND pins also lacking protective circuitry, this leaves only 3 options :
- adding a minimalistic protection, like a fuse, and hooking into them (someone in EE could help!) - the easiest solution
- using the battery pads with an external charging circuit like the one selling for $4, which will confuse the charging chip
- 4 wires lead, that one has to solder into the miniusb port, with something like the optocoupler hack. This might be complicated, but is
the safest route.

BTW charging only occurs when D+/D- are shorted. Could shorting them *while* using the external circuit help the charging circuit? (I don't know about it, but it won't help if it measures charging current during charge) Could it the charging circuit be forcefed information in the software space, when triggers such as D+/D- short are detected??

Guylhem