I want to ask a few questions that relate to solar panels and the charging of batteries. I have looked all over the internet for answers but have not found anything that answers my concerns. The most obvious ones I think I know already but just want clarification. Thanks in advance and I appreciate all the help offered.


1) If charging a battery by solar, could I theoretically wire many parallel solar panels together to increase the speed of charge without damaging the batteries, given the voltage is correct?

2) If I had a 12v 1amp panel, and 8x 1.5v batteries in a series, would that be ok to wire together, or must the voltage supply be 1.5v?

3) Connecting the positive and negative of a battery creates a short circuit. Does the same circuit, with the inclusion of solar panels create the same short circuit?

4) My background is programming, not electronics. Is writing my own MPPT algorithm and wiring up a charge controller feasible, or just a ridiculous idea?

5) If a series of batteries are charged, do they all charge roughly evenly, or does the last in the chain charge first?

6) What happens if batteries are charged in a parallel configuration?

7) To charge one battery, then the next and so on, is done with a device that I believe is called a charge controller. Is this correct?

8) If this is correct, is an MPPT controller the same thing, just with the addition of the MPPT algorithm?

9) Using panels with an output of 12v, 1amp, if I were to wire them into two series of 2 parallels...Is that 24v at 2amps, or 48v at 2amps?

Please be advised, I know C++, Java, PHP and such, not electrons and protons etc. Please respond in as simple way as possible. Cheers guys.


closed as too broad by Andy aka, Voltage Spike, winny, MCG, Finbarr May 22 '18 at 9:57

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    \$\begingroup\$ Have you googled any of these 9 questions? \$\endgroup\$ – Andy aka May 17 '18 at 9:53
  • \$\begingroup\$ Yes, I struggle to understand the way things are written sometimes. I think I know the answer to most, but simply wanted confirmation that I have interpreted it correctly in a yes/no format. I appologise that it's rather simple for you, but was just looking for clarification. \$\endgroup\$ – user4163554 May 17 '18 at 10:04
  • \$\begingroup\$ @user4163554 There are a few resources available on the internet, the first one being google.com/… you could adapt that tutorial to your micro or get a PIC and build an MPPT tracker to get a handle on the algorithm \$\endgroup\$ – Voltage Spike May 17 '18 at 17:10

Not the best answer, but considering the huge questions you're asking, here's my shot:

1) You need to wire the panels up depending on the panel output and cell requirement, this varies a lot between batteries and solar panels. I would suggest you research battery charging to understand this better. But yes.

2) The main issues you've got with this one is you're assuming PV panel have constant outputs. A 12V 1A panel will provide 12V and 1A under ideal circumstances, so depends on what you've got depends what they output. I think you need to do a lot more research about charging batteries to understand what you're really asking here

3) Yes, panels are often rated at an open-circuit voltage (voltage across panel under ideal lighting with no load) and short circuit current (current through a short circuit of the panels output under ideal lighting set up)

4) MPPT algorithms vary a lot depending on lighting and set up of panels, so I would say that making your own one is the better way forward.

5) Depends on the batteries. Another "do so research into batteries to understand" answer. But (all other things being equal) charge up at the same time, so be careful if they are not equally charged, as they could easily become overcharged

6) Depends on the batteries. Another "do so research into batteries to understand" answer. But with the correct setup, they will share the charging current between them

7) There are lots of things with that name, but probably.

8) No. An MPPT gets the most of the solar cell, it is nothing to do with batteries

9) That is parrallel vs series question. Currents add in parrallel, voltage adds in series.

  • \$\begingroup\$ Thanks for the advice. Most I already knew, I just needed them explaining to confirm. Thanks so much. \$\endgroup\$ – user4163554 May 17 '18 at 12:42
  • \$\begingroup\$ Again thanks for the response, each of your answers pretty much answer the other questions and clafifies most. However, there was something I wanted to ask as I am still unable to get my head around it. Question 9. I understand that voltage increases in a series and amps in parallel, but I am uncertain of the answer in terms of volts. I think after all you have said that the answer is 24v & 2a. \$\endgroup\$ – user4163554 May 17 '18 at 12:50
  • \$\begingroup\$ If you have two 12V in series, you have 24V. If you have two 1A in parallel, you have 2A. So, with four cells in a 2S2P set up, you have 24V at 2A. \$\endgroup\$ – Puffafish May 17 '18 at 12:55
  • \$\begingroup\$ Brilliant. That helps a ton. \$\endgroup\$ – user4163554 May 17 '18 at 13:11

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