My NOS Pismo batteries tend to last about a month on their own, but, need to be plugged in the night before use.
I have a pair of NOS 5300 packs. One holds a charge for a week (but runs for 4 hours under normal use) and is then useless. The other lasts 20min and then is "dead". both have excellent connectors/conductor pads.
The one that is near-death is going to get "chopped" and I will finish putting in new Enloop Pro cells (AA - 2500mAH). Factory cells were 2000mAH.
I did recell a NiMH battery for my old toshiba Satelite 133 pentium. I had to come up with a special adapter for holding the welding tool (10gage how wire that was 3mm apart at the tips) and used a 12v car battery with a car soleniod.
Scary as hell the first time I tested the setup, but, having practiced on some test strips and dead AA cells, I got the hang of it. I used cheaper Engergizer 2300mAH AA cells as they were 1/2 the cost of the Enloop Pro but still are better than the factory 2000mAH cells. [NOTE: Both the Enloop and 2300mAH energizer cells are "leak proof" designs]
I pre-charge all cells and run them down to ~10% using a flashlight and then charge them overnight before final installation.
I found that Loctite 2 part epoxy with a dab of Testors olive drab paint (kid makes models) got the color just about perfect.
The Loctite Epoxy "Plastic" Bonder is what I used and doesn't lend itself to cracking as bad. It is Nylon safe!