charging 12v battery with solar panels

[innovationhut]

Solar circuit

Hi,

I am thinking to do a project on solar panels. For that I have chosen to charge a mobile phone. I found out that the phone require 8 w to charge and a maximum of 0.8 A current.

Up to now i figured this out:

I am thinking to get SOLAR PANEL which outputs 12 w energy. so in theory this solar panel must be able to charge the mobile phone.

PLEASE advice me are there any other considerations that I need to think about. Moreover, any start up circuit on solar panels will be a great help.

Thanks

 

[BABESH]

Solar circuit

As solar energy changes, so does the o/p power from panel,
will this fluctuating solar energy be able to charge mobile battery successfully????, is there chance of over charging which may heat up battery...

--babesh.

 

[kspalla]

Solar circuit

you can adopt protection circuits like zenor, and I belive it should be possible.

first list out the specification of solar cell, driving another battery? then to cell phone battery.
check also on the battery charging circuit.

 

[Jcouls29]

Re: Solar circuit

12 W will work. The voltage won't change very much due to the sunlight, but the current will. So if you have sporadic cloud cover, the current will change a lot and their may be issues. There are a few things to consider doing for this circuit:

1) Put a schottky diode in series with the panel to protect it from battery back-feeding.

2) You may want to have a middleman battery as a buffer for current spikes. You will lose a little efficiency but it'll protect the phone battery from current spikes.

3) Definitely have some decoupling capacitors to smooth out the spikes.

Otherwise you just need to make sure the panels output the necessary voltage for the battery to charge. Good Luck

----------------
Justin
TheModernEngineer.blogspot.com