That's exactly what I though about It's also primary reason why it's going to be available only for body replacement, and not for "backcover only" - I would love to provide it for back's too, but it seems, that without changes in body itself, it's just not feasible.

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.[/quote]

4th option is to re-create lacking protective elements *before* pins, which, via initial consultations with specialists (joerg_rw) seems possible/feasible. Still can't promise anything, but will try.

Also would like to know, if it's possible to software'ishly "cheat" device, that wall charger is connected, without shorting pins. I would be useful for various purposes.

Even if not, and *if* (still not sure) it turns out to be feasible to use testpads, I would probably just add 2nd USB port - of course, it wouldn't allow to use 2 usb peripherals at the same time (via hostmode), but would allow to charge N900 with any charger/usb cable, and would also take care of pins shorting (wall chargers have this shorted internally or inside plug).

As for barrel connector, it's probably going to make it into final design - 90%, I would say. Even if testpads solution would fail, I can just leave it ready to be modded as per dr_frost_dk's instruction. Of course, it would be included *only* in "bigger" backcover, so people waiting for lite, flat one without much addons, don't need to worry.

No way, paralleling 2 batteries with different capacity won't bring any benefits (runtime = runtime provided by lower capacity one), and would definitely bring problems. Paralleled batteries absolutely *must* be of same type, chemistry, capacity etc = in practice it means same manufacturer and similar/same age.

I think that fund-rising via pre-orders is better solution - after all, it's niche project aimed @ our Community, and Community know about it already via this thread, IRC, etc. + kickstarter "steals" too much, 5x as much as "goddamn paypal" Everyone willing to support is really encouraged to do pre-order. BTW, thanks for kind words.

/Estel