i have made a solar charger using this circuit:http://electroschematics.com/4746/solar-charger-circuit/
it works fine but the problem is that my solar panels are giving an output of around 600ma, but when i test the battery to check how much current it is taking i find out that that its only using 300ma, thus it charges very slow.
why is this and how can i fix this? should i use a constant current supply (using lm317 as a constant current supply) but then how will i regulate the voltage, should i use 2 lm317 one for voltage and one for current would that work???
That circuit senses the battery voltage and backs off the charging as the battery becomes fully charged - it also is adjustable. Perhaps the battery isn't flat? Perhaps you haven't calibrated the adjustment.
You can't separately control both voltage and current, the battery constrains the relationship between voltage and current - indeed that is its function.
Also what is the voltage of your solar panel - you'll need overhead to deal with the regulator drop-out and the fact you want to draw full current. If its less than 10V that might account for lower current.
thanks for your help
my solar panel is giving aroung 18volts, and if i max the pot on the regulator i get 12v at 220-300ma only.
http://www.diypvsolarenergy.com/typical-solar-panel-system-schematic/
Simple charging technics:
http://www.evilmadscientist.com/article.php/solar
Smart charging:
http://www.lged-rein.org/archive_file/01057.pdf
Google for "Solar Panel Controller Charger schematic" to find more.
The Arduino playground could use some work on this ever popular subject....