How to Build a Solar Panel Optimizer Circuit

A very easy yet useful solar optimizer circuit can be created by utilizing a LM338 IC and a few opamps.
Let’s appreciate the offered circuit (solar optimizer) with the aid of the following points:
The figure demonstrates an LM338 voltage regulator circuit which contains a current control function also by means of the transistor BC547 linked across adjustment and ground pin of the IC.
The two opamps are set up as comparators. The fact is a lot of such phases might be provided for improving the results.
In the existing design A1’s pin#3 preset is modified such that the output of A1 goes high when the sun shine intensity over the panel is all about 20% lower than the peak value.
Likewise, A2 phase is changed such that its output goes high when the sunshine is about 50% much less than the peak value.
When A1 output goes high, RL#1 causes linking R2 in accordance with the circuit, disconnecting R1.
In the beginning at peak sun shine, R1 whose value is chosen a lot lower, permits highest current to reach the battery.


When sunshine drops, voltage of the panel also drops and now we are not able to manage to obtain heavy current from the panel simply because that could reduce the voltage below 12V which may completely quit the charging method.
Consequently as described above A1 comes into action and disconnects R1 and attaches R2. R2 is chosen at a higher value and enables only restricted amount current to the battery such that the solar voltage is not going to crash below 15 vots, a level that’s imperatively needed at the input of LM338.
When the sunshine drops below the second set threshold, A2 triggers RL#2 which often switches R3 to render the current to the battery even lower making certain that the voltage at the input of the LM338 by no means drops below 15V, yet the charging rate to the battery is actually preserved to the closest optimum levels.
If the opamp phases are improved with more selection of relays and following current control actions, the unit may be fully optimized with even better effectiveness.
The above process charge the battery quickly at high current during peak sunshines and lowers the current as the sun intensity over the panel falls, and in the same way offers the battery with the right rated current such that the it gets totally charged at the end of the day.
What Goes On with a Battery Which can not be Discharged?
Believe in the event the battery is not optimally discharged to be able to undergo the above procedure the next morning, the circumstance could be fatal to the battery, because the initial high current may have harmful impacts over the battery mainly because it’s yet to discharged to the stipulated ratings.
To verify the above issue, a few more opamps are launched, A3, A4, which monitor the voltage level of the battery and start the identical measures as done by A1, A2, to ensure that the current to the battery is optimized with regards to the voltage or the charge level present with the battery throughout that period of time.