Custom battery replacement

Hey,
Any of you guys replaced the battery inside the Bionx case with a custom made replacement battery?

I was looking inside the case and the battery is a 20 D-cell configuration, 7/6/7 cells in 3 rows to make a common block.
It has three wires, +red -black and (NTC)white (discharge temp). There are also 2 black wire that attach to a charging temp. fuse glued to the outside shrink wrap.
All original wires could transfer to new pack.

Of course, also inside the case, is a circuit board that contains the alarm, relay, charging recepticle etc.

A 10amp pack could be made for about $200.00, with quality common available cells, which would be a 20% gain in duration. (based on 24v 8amp NiMH original) That seems like a cost effective option to buying a whole new Bionx battery/case, when the need arises.
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