# Nokia BLJ-2 Battery Refurb

I have a couple of old Nokia banana phones, an 8110 and an 8146 which
both have dead batteries. If you should manage to find one of these
batteries second hand, they are extortionately expensive.


## Battery Disassembly 

Dismantling the battery is fairly easy, carefully insert a spudger /
guitar plectrum down the seam on the inside of the battery and gently
pry it up. There is some black adhesive used to stick the cover to
the battery so you may want to get something longer underneath to pry
closer to the adhesive until you manage to separate it.

Once the outer cover is off you can see the cells and the circuit
board. I carefully separated the battery cells from the casing along
with the circuit board. To separate the battery from the circuit
board I initially gently worked the circuit-board back and forth
until the metal battery tags sheared. After this I used a soldering
iron to remove the remainder of the pads from the circuit-board and
added a little fresh solder for later.


## Parts

The BLJ-2 battery is rated at 7.2v and had two cells. I figured if I
could find two 3.7v cells of a suitable size then I could wire them
in series to achieve close to the voltage I needed.

Having measured the available space inside the battery housing, and
looking around at various battery packs, I discovered that two 503040
battery packs could be fitted to replace the original cells. Each of
the packs is rated at 600mah 3.7v. 


## Fitting

The battery packs come with a circuit board attached to prevent over
voltage, and other things, but this seems to get in the way of using
them in series and also there isn't space inside the housing for the
batteries with these fitted, so I removed them. I cut the battery
tags as close as I could to the circuit board with side cutters,
being careful not to short the battery terminals.

Once that was done I tinned the battery tags with a little solder and
then placed them inside the battery shell along with the circuit
board ready to wire everything up. Here I think a picture best
explains what has been done[1].

The final assembly is quite snug once the cover is popped back in
place. I used no adhesive to secure the new cells or cover and
nothing appears loose.


[1](gopher://gopher.icu/I/images/blj-2.jpg)