So my cordless phone died and at the end of troubleshooting I found that it was the battery that was no longer working.
Several phone calls (I used the old phone) later I found that the cheapest battery pack was $19 plus tax.
Some observations of the original pack revealed that the pack was the size and voltage of 3 Ni-MH AAA batteries.
I could buy 3 of these locally for less than $1.75 each.
NOTE do not use regular AAA batteries for this as you will produce battery waste and possibly electrically destroy your phone from the higher voltage that a regular battery has or start a fire if you forget and plug it into the recharger...
This procedure should work with most cordless phoned that have a molded battery compartment.
Step 1: Remove and disassemble
First you will need to remove the old pack and disassemble it for the parts..
You will need to cut the shrink wrap off and harvest the wires.
The wires will need to be either cut off or de-soldered.
I chose the later route and desoldered the wires from the pack, possibly from remembering all the movies telling you not to cut the red wire...