Friday, November 20, 2009

Ugrading a NEC 900c battery and WIFI antenna "Battery hack"

I have had for sometime now a NEC Mobilepro 900C upgraded of course with the newest possible software and Cmonex is the one to take all the credit for that.






However the battery hasn't been keeping a very healthy charge lately which is more or less normal since it is quite a few years old to say the least.










While trying to open up the power pack in order to change the old Li-Ion cells with newer ones, I made a hole in it :(((











The problem was you see that having opened other batteries in the past for the same reason the plastics were far too strong and difficult to separate them.
This one on the contrary was very easy to open, and the plastics quite soft.

Thankfully I was lucky not to damage anything in the controller circuit, or the cells themselves. Also another lucky thing was the position of the hole. Why ? Here is why:

Sometime ago I got a short WIFI PCMCIA prism card which was not protruding from the NEC. Unfortunately this card needed an MMCX antenna to work and I had gotten a very cheap bare antenna from an Ebay seller in China.










The antenna is a bare PCB, a cable, a core on the cable and the mmcx connector.

I used to have it with duct-tape glued on the side of the screen (after a bit of chopping) since it has approximately the same width. Now however I could put it inside the battery!










When the battery is opened, there are four plastic chunks. Their function to keep the cells steady into position. And there is quite a bit of free space in there. Especially since the antenna is very thin. 2-3mm thickness.










Hence it can be very easily be placed at the side of the batteries, with no problems in space requirements.










the finished product :)


And some photos with the whole assembly.




















I have to say that I don't know if the antenna so close to the battery could cause any disruptions on the signal, but I will keep you posted

The new battery cells are not in yet, but are on the way so in a few days I will be able to enjoy, if all go well, a few hours of NEC 900 use.

Update:
The new battery cells finally arrived from Dealextreme.com and were put to good use immediatelly. The results were more than awesome. With the previous aged cells There was barelly enough juice to keep the mobilepro alive for 1:30 hours watching a movie. With the new 3000 mAh pack I can watch the same movie 3 times over with the processor ovelclocked !!!

The soldered batteries can be seen bellow. Not very elegant work I must admit, but it works like a charm











Cost of the hack:
1£ for the antenna,
11$ for the batteries
20€ for the wifi card
all and all, not bad I 'd say

3 comments:

  1. HOLA BUEN DIA, Y LA NEC PRO 780 ES DEL MISMO TAMAÑO QUE ESTA

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  2. Si no prende al principio cuantas horas debo dejarla para que emita luz

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    Replies
    1. hi, it has been a long time since I used my NEC 900C. I still have it somewhere, but don't really use it. I hate the fact that windows CE must always be powered on to not lose data.
      I do not know why your light might not light up. Perhaps if the battery is very depleted, it will not charge straight away. You need to check for yourself how long it may take. You also need to check if you upgraded your 18650 cells, that it has strong solders and it has not desoldered. Best of luck

      hola, ha pasado mucho tiempo desde que utilicé mi NEC 900C. Todavía lo tengo en alguna parte, pero realmente no lo uso. Odio el hecho de que Windows CE siempre debe estar encendido para no perder datos.
      No sé por qué tu luz podría no encenderse. Tal vez si la batería está muy agotada, no se cargará de inmediato. Debe comprobar usted mismo cuánto tiempo puede tomar. También debe verificar si actualizó sus celdas 18650, que tiene soldaduras fuertes y no se ha desoldado. La mejor de las suertes

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