Renew NiCad Batteries

Don't toss those weak NiCad batteries...  OK, we have all experienced the NiCad Battery memory effect.  That cordless drill or saw begins to loose its vigor, doesn't last as long, and this can be maddening when you have a job to do.  My Ryobi 14.4 Volt cordless drill would drive 3 inch screws all day long when it was new.  But after a while it starts getting weaker, doesn't last as long.  A while later the thing is useless, and you have to buy new batteries, or at least the manufacturer wants you to...

What is happening to your NiCad batteries is there are microscopic shorts that form between the electrodes in the battery, and the short out parts of the battery.  This is a drawback of the Nickel Cadmium battery architecture.  These microscopic shorts form, and it creates the "memory effect" where the battery looses capacity over time, and is eventually worthless.  There are a lot of people that have worked around this problem with various techniques.  There are various ways to use high current pulses to annihilate the dendrites that short out the electrodes in the battery.  What I found through research is that you can use the battery's charger itself to do this for you.

This case is the Ryobi 14.4 Volt series, a strong battery, and device when its new, but when the dendrites grow in the battery it quickly becomes worthless.  When the battery get internally shorted out the green, and yellow lights on the charger come on together, and this indicates that the battery needs to be replaced.  You can find many people on the internet (You Tube) that have figured this out, and developed a work around to annihilate the dendrites.  Basically they use the inrush current of plugging the charger into the AC Voltage to generate high current pulses to the battery.

Plug the battery into the battery charger, then you will see the green, and yellow light come on simultaneously, indicating a not chargeable state.  At this point unplug, and replug the charger from the AC outlet, allowing the inrush current from the AC to generate higher than normal current pulses that hit the battery, annihilating those damn annoying dendrites.  The basic NiCad charging circuit could be redesigned with a pulsed high current technique that would make the dendrites, and the memory effect history.  I am putting this theoretical technique to the test now...

 The next morning I developed this into a process.  I'm lining up the batteries, and run all of them through the process several times.  When one gets the green light I'll pull it off, and put the next one in line on the charger.  Then cycle the AC power 10 times.  I think the process is working because they are charging longer, and getting stronger.  There was one battery that was dead dead, nuthin', and now its running the drill at full power.  The real test will come when the Sun comes up, and I can start using the power tools...