Posts: 1,788
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Joined: Aug 2007
If you have the old battery pack, it can be rebuilt by Batteries Plus, Batteries, Etc. or other similar battery places for around 20-30 dollars depending upon the cells used. I prefer to use the highest capacity cells available (2000-2400 mAH). They are not as apt to be damaged by the rather high charge current that HP dumps into these packs if you leave it on the plug for extended periods.
If you don't have the old packs you can try to find them on the Classifeds here or Ebay.
A third alternative is to have a four cell (sub-C size cells) pack built up at the battery store with wire leads then either wrap the leads several times around or (gasp!) solder the leads to the terminals in the battery compartment.
Posts: 1,162
Threads: 26
Joined: Aug 2005
If you have the old battery packs, it's possible to rebuild them. You cut open the plastic housing along the joins, and take it apart. Inside are 4 sub-C size NiCd cells. Recover the terminal strips from the original cells and buy 4 new tagged (i.e. with solder tags) ones. Solder them together in series (to make a 4.8V or so battery), then solder the original terminal
strips to the 'ends' of the cells, making sure you get the polarity correct (same as the original of course).
Put the new cells into the housing and try it out. If it works, then glue the housing together again with something like 'plastic weld' or a similar solvent-type adhesive.