Homemade Battery Charger for NiCD NiMH Lithium
Unless you use your cordless tool batteries, every day, they sit and when you do need them they often don’t have a full charge from self-discharge. Fast chargers are quick, however, they reduce the charge/discharge life cycle number from gassing which can’t be reabsorbed as quickly as the gas is generated.
Mike from Michigan shows you his solution.
How to build a trickle charger/battery maintainer.
It slowly charges NiCD, NiMH, and Lithium up to 18v. it can easily be built to include up to 24v. This device keeps your batteries fresh and ready for use for years by leaving them hooked until needed. It can easily be used with 120v or use with solar panels for a Solar Trickle Charge in remote barns and locations. It has onboard ammeter for individual current adjustment up to 100ma.