Solar light ics are very handy they have the dark detection circuit and the voltage multiplying led driver built into one small four pin component.
Solar panel circuit.
When you connect two or more solar panels like this it becomes a pv source circuit.
In this circuit the solar panel charges up a 3 cell nimh battery 3 6 v.
This circuit makes sure that the voltage from the solar panel never exceeds the safe value required by the battery for charging.
Dc is then converted into alternating current ac through a device called an inverter.
Between the two is a reverse blocking diode.
Dividing by 50 depth of discharge as you choose flooded that is 18000 0 5 36000wh or divde by 0 8 if for agm batteries that is 18000 0 8 22500wh.
In order to regulate the voltage from the solar panel normally a voltage regulator circuit is used in between the solar panel output and the battery input.
When you connect the positive terminal of one panel to the negative terminal of another panel you create a series connection.
Ac electricity flows through every outlet of your home powering the appliances.
Using the solar light ic all you need is the solar ic an inductor and the ultra bright led to make the circuit.
He needs batteres to supply the 1500w loads for 12hours at night.
Add the battery and the solar cell and you have a solar light.
A relay is introduced in the circuit and is wired with the led module such that it s switched on only during the night or when it s dark below threshold for the solar panel to generate the required any power.
One positive and one negative.
This one way valve allows current to flow from the solar panel to the battery but does not allow current to flow backwards out of the battery through the solar panel.
The solar panel voltage specs may be anywhere between 18v and 24v.
I am not sure why you said 2pcs of 120ah12v battries in series.