solar battery charger

Hi everyone


So this is a circuit of a charge regulator for solar panels. the aim is to charge the battery with 14V then 13V after a moment before its totaly charged. To do so we will need the PWM of arduino to open the MOSFET when the voltae of solar pannel is higer then the battery's then when its opposite arduino shut down the mosfet. the zener diode is here to limit the voltage to 15V.

so what do you think ? is there something to correct ?

Hi,

Both voltage dividers are not correct.
Add some headroom for the measurement range.

The zener's anode needs to be connected to GND if you want to limit the voltage.
Be aware that it will disspate all the solar power into heat. I don't think it's a good way.

There are no capacitors to store energy and reduce EMI.

Klaus

This is the third forum that this horrible circuit is shown in.
The little zener diode is rated at only 17mA so it will instantly burn out if it is grounded.
The Mosfet is a follower so for it to turn on then its gate must be fed about +25V from the Arduino.

The zener will drop about 15V and you will be left with around 2V to manage your affairs.

Therfore you cannot charge a 12V battery with only 2V with a Mosfet that does not turn on.

If your battery is big (say 100AH), then perhaps you can directly connect the solar panel (only 20W) via 2-3 diodes (in series). The max battery voltage will be 14.4-14.6V, the three series diodes will drop about 2.4V and if the solar panel is giving full power then your battery will get happily charged. Usually solar panels can be considered as const voltage devices in the sense that the current output depends on the light intensity but not the voltage (within limits). But the voltage will depend also on the load because they DO have finite impedance.

ELSE, you will need a regulator.

If your battery is small (compared to the capacity of the solar panel, 20W in the present case), then you MUST control the current and monitor the voltage- continuously.