Right! As far as I can tell, the little "computer" inside the battery expects all the cells to be a minimum of 1.6 volts before it'll allow the main computer (iBook itself) to charge them. What happens when the batteries become un-chargeable, I've found, is that one or more of those cells dips below that minimum voltage, which deactivates the circuitry, and manifests to the user as a battery that won't take any charge (the computer will try, as indicated by the indicator light glowing amber for awhile), doesn't charge at all (the computer won't even try, and the light stays green to reflect this), or isn't even recognized (indicated by a battery icon with an 'X' through it in the OS).
In California, I've never seen soldering irons in any Walmart stores I've been to (I haven't even looked, honestly, mainly because I've never needed one except occasionally, and I never thought to look around Walmart to get it). Perhaps over there in Georgia, Walmart does carry such things.
c