AllDodge, when I was still working, my Engineering team was tasked with building a better "mousetrap" (battery charger) for a unique battery pack used onboard certain aircraft. And while that battery pack was NiCad in design, we studied and learned so much about batteries in general. Seem NiCad's specifically, charge to what is called a "knee over" point. Basically as the batteries charge they get to a point of increasing voltage and then drop back just a little indicating a full charge. So we used a microcontroller to sample the voltage every couple of times a second and store that reading. Then after X numbers of stored reading we averaged them to see if the battery pack reached their knee-over point. And this continued for the entire charging process. Once the knee-over was reached, the charging system switched over to a monitoring system. So depending on the capability of any NiCad pack in existence, their fully charged knee-over could be slightly different then any other pack or that same pack previously. So there wasn't any preset voltage point that had to be reached to indicate a fully charged battery pack that we see used in most battery chargers. In other words each battery could have its own peak knee-over voltage point (fully charged) and not some predetermined set voltage that so often cooks batteries with normal charging algorithm that rely on continually charging until that set voltage is reached. That is an accident waiting to happen so many times... Are design made it so much safer to use that the battery packs actually started gaining amperage capability back to their original capacities. We interfaced this charger circuits via a digitizer (UE9 Lab Jack) to our computers and could actually see the knee-over curves so easily...
