There are always caveats to everything however.
Do i need a charge controller for solar panel.
Keep in mind that you don t need one when the panel releases less than or equal to two watts for every fifty battery amp hours.
If you have a five watt panel in the above example you take 100 divided by 3 300ma and you come up with 333 3.
Since this is larger than 200 you do not need a charge controller.
Since this is less than 200 you need a charge controller.
If you have an mmpt solar charge controller you have the room to get higher wattage solar panels at 24v or 48v without loosing to much power.
In general you do not require a charge controller that usually requires the minimum maintenance or drop charge panels including but never limited to the one to five watt panels.
Last summer i finally had the opportunity to set this up for demonstration with a small 12w solar panel and two different battery banks.
However you still need a blocking diode to prevent the battery from discharging to the panel at night.
For further reading mppt pdf.
It does this by using a transistor to shunt the pv charging circuit.
I get asked this question quite often and the answer is almost always a resounding yes.
This means if your battery is full it stops the charging and if your battery is reaching an unhealthy.
The charge process is performed in a smart or intelligent way.
Solar charge controller functions.
A solar charge controller is designed to receive power from a solar panel or array of panels and use it to charge a battery or bank of batteries.