What is float charge?
It is simply a method for maintaining the charge in a cell or battery – float charging is used anywhere that batteries are used infrequently, but must be kept at full charge when not in use. While I do not intend this simple project to become a full scale article about batteries, it is very important that you understand that unless looked after very well, any battery will have a much shorter life than normal, and will prove very costly to replace. It is entirely up to the reader to determine the suitability of the charger shown to the intended application. Please note that any modifications to this project are left entirely to the reader, and I will not provide any further information via e-mail, so don’t ask! Description The charger is shown in Figure 1, and is a conventional (but very simple) regulator. A 3-terminal regulator is not suitable for this, as the voltage across it will be too high if the batteries are discharged. The charger uses a standard 15V transformer (which connects