hi guys,

just dropping by to say i'm very interested in this project. i joined this forum just to be able to vote the poll. unfortunedly it looks like the price will be to high for me. i would gladly pay 300 euro for a complete neo900, maybe even up to 400 euro's. but anything higher is to much for me . anyways, i really hope you guys will succeed! and maybe there will be enough demand so the price drops below 400 euros

Just a thought (that may be totally unrealistic due to my lack of knowledge concerning electr(on)ics):

The N900 battery BL-5J [1] has these specs:
3.7 V; 60 x 38 x 5.5 mm

A NiMH AAA (micro) battery [2] usually has these specs:
1.25V; 44.5 x 10.5 x 10.5 mm

A NiMH AA (mignon) battery [3] usually has these specs:
1.25V; 50.5 x 14.5 x 14.5 mm

So physically 3 AAA batteries or 2 AA batteries would fit into the battery bay if one has some custom back cover (the Mugen one should already be able to house AAA batteries) and some sort of adapter that would still have to be designed.
3 AAAs in series connection would even come pretty close to the 3.7V of the BL-5J. I'm not sure if 2.4 V that two AAs could provide might even be worth discussing.

So would it be feasible to design the board in a way that it can accept 3xAAA (or maybe even 2xAA) cells?
What I absolutely don't know is if NiMH and Li-Ion have some fundamental difference in behavior that would exclude an idea like this.


[1] http://www.cpkb.org/wiki/Nokia_BL-5J_battery
[2] http://en.wikipedia.org/wiki/AAA_battery
[3] http://en.wikipedia.org/wiki/AA_battery

NiMH an Li-Ion batteries are charged with a diferent system. And moreover that NIMH batteries will have much less mAh than a LI-Ion battery of same size so will last much less

I know. What I don't know is what exactly that difference is and if there is a way to reasonably implement both systems on the same board.

I have NiMH AAA cells with 1.1Ah at home. That's not that far away from the 1.32Ah of the BL-5J.

You need to supply ~3.3V MINIMUM for the n900 to not die on it's arse.

You can get a bl-5j with 1500mAh. I am sure I even had one that was 1600mAh.

Even if your NiMH are 1100mAh, you will need 3 of them in series to make the minimum voltage. But you would still only have an 1100mAh battery.

In short, it would be pointless.

Thanks!

Correct.

My point is, that there's a chance the Neo900 might be my very last "smartphone", most likely because one day my eyes will be too weak to decipher a 3.5" display.
That day probably is 15 or 20 years in the future. I'm not sure if BL-5Js or something compatible will still be around at that time. But I'm pretty sure AAAs will be.

Someone else (certainly not me) might bring up that even today out in the wilderness finding some spare AAA cells might be easier than finding a BL-5J.

3*AA = 3*1,65V(max_alkaline)=4.95V -> phone fried
3*AA = 3*1.20V(C60%_alkaline)==3.6V -> close to modem shutdown

So you can fry your phone with full alkaline primary cells, while discharging them from 100%->60% already gives you a non-operable phone.

http://en.wikipedia.org/wiki/Alkaline_battery#Voltage
/j

In 20 years in future, your mobile will maybe be an small on-ear gadchet, a molar implant and some glasses.

Or maybe just a direct brain implant XD.

gin 2ß years i will find my n900 and make some incredible things with it and smile

See also here. Some of these vendors may need to contacted to find out what's available. It seems Hynix also do an 8Gb LPDDR 168 ball PoP.