14V(***better if 13.5V***) is MAXIMUM (!!!) for a normal-12V-car-battery (measured at the battery’s-terminals : “+”&”-”) … see 12V car battery FEATURES ( data about car-battery-PROTECTION ) ! … ( I presume you don’t want the battery to starts “BOILING” itself ! ).
With respect.
………………….
* NEW TUNER * : with *filament*(!)-car-bulb and diodes.
CIRCUIT – DIAGRAM.
7555 (Mosfet 555) & IRF640N.
*** Very low consumption : bright light with two LEDs-bulbs = about 0.5W !!! ***
*[ Two 12V(13.5V)-LEDs-bulbs (modified from 230V-LEDs-bulbs) !!! ]*
Small Battery : 12V/10Ah (type: UPS).
When the solar panel generates 22V (on a sunny-day), the NEW TUNER keeps the voltage at ab. 13.5V [ 22V before the TUNER, 13.5V after the TUNER (13.5V sent to Battery)].
The Battery must be protected with voltages between 12.5V and 14V(MAX.) !
PS :
About 22V ONLY from the Solar-Panel (when sun), ( without the Battery and also … without the Electronic-Circuit ! ).
About 17V ONLY from the Solar-Panel (when cloudy), (without B & without E-C !).
About 13.5V with all (S-P & B & E-C).
NOTE :
*14V* is *MAXIMUM*-”feed” for a normal *12V-car-BATTERY* !!!
See the features of a normal Car-Battery-system ( the Alternator-*RELAY*-*BATTERY*-section !!! ).
***The Voltage measured directly at the battery-terminals should NOT exceed 14V [ I do NOT want to "boil" (ruin) the battery(type: lead&lead-oxide) ! ].
NOTE2: (19 February)
It is very stable (it works very good), also when cloudy ! (normal solar-panel)
Post time: Jul-17-2017