Lately, I noticed that the battery capacity of my power drill has been diminishing. It has been my habit of fully charging the nickel cadmium battery pack before I store it. And every time I put the drill in action, it starts and slows down drastically. I have to throw it back to the charger and have it fully charged before I used it again.
So this time, with all the lithium ion batteries I collected from old laptops, I decided to replace the aging nicads with these high end lithium ions. I made sure that the batteries are all balanced charged to 4.25 volts and equal to their holding capacities which I measured to 2300 mAh averaged.
I was able to cut tin strips from the garbage biscuit container to connect the batteries together. I made sure I used the better power soldering iron. A 40 watts worked well, for quick solder transfer, dissipating the heat faster, avoiding too much heat to the batteries.
With one drill that uses 18 volts, I decided to install 5 lithium ions in series, that is 18.75 working volts. The 24 volts drill, I managed to put 7 in series, that is 26.25 working volts. So far, both drills has been working flawlessly with lots of power, no overheating. Next plan is to build or buy the suitable chargers. On the power and weight, what a huge difference!