As a disclaimer, I'm a novice when it comes to electrical engineering and I am looking for assistance in order to complete my endeavor. I have spent the past few weeks teaching myself concepts and have designed the following circuit, but still have a few questions.


I am building a project with a goal of having on-board electronics (ESC, motor, receiver, etc.) get power from solar cells when there is enough sunlight, and get power from both solar and battery when there is not enough sunlight. Additionally, if there is excess power from solar, the extra power should trickle charge the battery, since the battery and solar cells are connected in parallel and the energy flow is decided by Kirchhoff’s current law. A receiver controlled switch will be used to connect/disconnect the solar cells depending on need.

Below I have attached the circuit I designed and the questions I have about it.

block diagram of design

My questions regarding the circuit design are the following:

  1. How can overcharging the battery be avoided?
  2. I am thinking that an MPPT is not needed since the battery and solar panels are well adjusted in parallel. Is this a good idea to not have a MPPT because of that and because a MPPT is a heavy device with some power dissipation?
  3. Is the Schottky diode necessary in the setup (since the solar cells themselves act as a diode and would only be damaged if there is much higher voltage)?
  4. Would my current setup achieve my goal?
  5. Do you have any other recommendations?
  6. Is there any small electronic device that I can add that will help me monitor the voltage of battery from a far away distance?
  7. I think that LiPo balancing is not an issue since the LiPo will not be too deeply discharged or with high current. Is my thinking correct and if not how would the battery be balanced while charging through solar?

Thank you very much for your time and help! Have a great day.

  • \$\begingroup\$ You cannot renumber the questions after you've received any answers which use the "old" numbers, because that changes the meaning of those answers. Instead I've added your new questions, with new numbers, and removed questions which you no longer want, by using HTML "strikethrough". \$\endgroup\$ – SamGibson Jul 9 '18 at 13:48
  • \$\begingroup\$ Thank you sir. Sorry I am a bit new to this and didn't look at it. \$\endgroup\$ – krishna Jul 9 '18 at 13:52
  1. It cannot.

  2. wrong MPPT will improve efficiency and regulate Vbat charge CC, CV and cutoff if you buy the right one.

  3. Wrong , diode is necessary

  4. No it won’t work . Look harder for solutions


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