Interesting, will need to build something like this shortly, need to get parts 
first 

PE3ES

> On 27 sep. 2014, at 00:51, DK7FC <[email protected]> wrote:
> 
> 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 :-)
> 
>