@Ivan...I use a lot of NiCds and actually made up a "rejuvenator" for them to zap them with a high current for a short time, discharge, then zap again. I did this with a 555 and entered it for the 555 competition a couple of years ago, the circuit is here:
Mixed success, some batteries can't be fixed, but on some it works a treat. You need to put a battery on the rejvenator for an hour or two, then give it a full charge at the normal rate. I have specified 2C zap (ie a current of twice the AH capacity of the battery) but you can go to 5C or more for stubborn ones.
I just use a high current supply (eg a PC Power supply) but you can also use a capacitor to give the "zap". I prefer a high current supply as it gives a more sustained and controllable zap.
@Rgarvin640:Yes we used to manually use the lab power pack to step up the current to a dead NiCad untill the voltage started to drop and then discharge with a short, some times it would blow the short.
I have a lot of tales about battery use in London Underground Trains and before they were sold off Bus batteries.
I love the single cell lead acid batteries we used on the battery locomotives used to maintain track. They were very big 3 foot high an 1 foot deep float charged from the track 660 V DC during the day.
Ivan: Some where in your articles it would be helpfull to discuss the shipping issues with different battery chemistryies. This is something that can catch both designers and PM's off guard, at least the first time they go thru it. :)
Crusty1: There are many 'rejuvinator' devices that are used here in the states for large truck batteries. If you can get an extra couple of months usage out of a battery it is worth the 8-10 hours that the process takes.
Also, Nickel Cadmium types were notorious for growing metal-fiber 'wires', that would partially short out a cell. There appeared a capacitor-based rejuvenator that would pulse a high-current into the cell to blow out the metal fibers and breathe new life. A similar treatment was touted to break loose sulfation in lead-acid cells. The applied voltage waveform shape and duration was critical to keep from doing too much damage. In some cases, it killed the remaining life, but was sometimes worth the risk.