73, Stefan

Am 27.09.2014 00:51, schrieb DK7FC:

Hi all,

Since today, my solar powered battery in the garden is charged by this solar battery charger, https://dl.dropboxusercontent.com/u/19882028/20140927_004153.jpg It took some time until i found the circuit that suits my requirements. The losses are very low! The supply current of the circuit is just 40 uA!. The circuit is a comparator design which generates no QRM during ON and OFF times. The switching transients are relatively slow (not like in usual switch mode supplies). The hysteresis causes a switch-off voltage of 13.9V and a switch-on voltage of 13.3V. The high current diode which is a very low forward voltage drop is taken from an old SMPS...

Just in case someone want to play with similar stuff and likes to have some ideas...

73, Stefan/DK7FC

PS: Yes yes yes, of course the may be similar circuits in the web and someone has done it before. But it wasn't the goal to do something the first time, as usual :-)