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My 2225B Thinkjet printer battery pack is dead: How can I recell it ?

Posted by Etienne Victoria on 25 Oct 2005, 5:10 p.m.

Credits: Information in this article is sourced mainly from Tony Duell's and Katie Wassermann former posts in the MoHpc forum along with my own experiments.

To rebuild the 2225B battery, you will need : 6 Sub Cs Ni-CADs or NiMh, one picofuse if the one in the pack is burned, strength.

Choosing Ni-CADs or NiMh is a matter of use and taste. You'll get a higher capacity with NiMh but a higher self discharge rate. NiCads provide the reverse strongpoints and drawbacks.

DO NOT mix both types. If you're not sure of yourself about the charging mode, I advise you to use NiCads.

a) Open the thing : The case is not welded but snapped, just exert enough pressure with the largest flat screwdriver as the innards are tuck with very strong double-sided tape : after releasing the cover on all edges (it's got clips all round), use a flat blade to prise it from the cells.

NOTE polarity of the existing cells connection alongwith picofuse position!!!

The picofuse is a 25V 5A fuse as pictured:

b) Desolder and dispose/recycle the old cells SAVING the picofuse you'll find between them. Final empty shell looks like this:

c) Assemble the new cells in series with the picofuse (picofuse position & polarity not strategic)

d) Resolder to the pack circuit, respecting polarity (+ to red wire, - to black wire) to wires shown:

and insert in pack with very strong double-sided tape ON THE BOTTOM. This will avoid the cells moving randomly in the pack except if you want to build special marracas.

e) If you really wish to recreate new problems and stress when opening again, apply same tape to secure the upper cover.... Otherwise refrain...

f) Reassemble cover.

g) For the first charge, charge the pack OUTSIDE the Thinkjet, monitoring carefully smells, gassing, funny noise, sparkles....

g) Test voltage at 7,2V loaded and use.

Edited: 23 Feb 2009, 4:49 p.m.


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