Mismatched Solar Panels- Same amps, different volts and watts

Here’s another of our mismatched solar panel series,. We’ve taken two solar panels, one 24V 100W and one 12V 50W. They both have a current rating of 3 amps. We tested to see which method of wiring them together, series or parallel, works best. We have an MPPT solar charge controller and a 12V battery, with meters measuring the volts in, volts out, and current out.





  • I have 3 solar world 60 cell panels, 290 watt. I want to install 6 canadian solar 315 watt in parallel with the 3 290 watts panels. The voltage, amps are very closely the same. I know that the the system is going to work at the lowest rate, but is any additional info to consider for this combination??

  • Please suggest me 250 watt 24 volt pannel 150watt 24 volt pannel joined together series or parller

  • There is a reason solar panels are measured in WATTS. Watts is what is important and a much better use of comparison.

  • Hi, can we connect 24v solar panel to 12v battery….suppose if not means why and what is reason?

  • Hi Amy,
    I have 2 * 265 PC in series 24v system.
    I have issue: my MPPT chage controller ( 60A )gives 2 to 4 amp normally in very good day and volt about 26. However when I turn off and ON again then for while it gives high amp to 14 or 16
    After half an hr or so it go back to same problem. I bought new MPPT charge controller 60A it behave same way…

    What could be the problem?

  • Max Power Point Transfer. mppt. each panel has a different mppt point. how does a charge controller know at what voltage and amps the mppt should be at if every panel in series is different. answer. it doesn't and most mppt controllers will go into limp mode with this set-up . best off with the less efficient but more suited pwm charge controllers in this case.

  • Great vedeo. I will like a video connecting different charge controller into a battery bank. Like a solar panel charge controller and a wind turbine charge controller together. Or 2 solar panel charge controller together.

  • Hi Amy I have 2 miss matched solar panels 1 is 300 watts open circuit voltage 22.32 – short circuit current (A)17.83 -max power voltage 18 – max power current (A) 16.67. second panel max power 175watts – voltage at Pmax 35.2 v – current at Pmax 4.7 A – open circuit voltage 43.6 V – short circuit current 5.48 V if I understand you correctly if I buy 2 separate mppt controllers I can connect the both individual to my caravan batteries and have them produce there max output. cheers Bill

  • What kind of monster actually puts a thumbs down on these videos..

  • Can we connect same voltage different watt and amp

  • This helped a lot! Thanks! Would it be too much to combine a 36V 50W panel with a 12V 200W one?

  • How much amps is ok to charge a 200 ah battery?

  • Great explanation, thanks! Would you be able to test solar panels in series (as per your last test) and then cover up one panel to see if the performance is still ok?

  • You're going to want a voltage passthrough between them in series or you're going to burn one of those panels up.

  • im sorry I've cant follow you at all you are throwing out a million numbers and phrase's and I still don't have the answer .

  • How this setup works with 12v panels but 1- 200w; 1-100w with a PWM charge controller, any help will be appreciated, again thanks.

  • I have to say your videos are spectacular, thank you for putting them together! 🙂

    I had a related question, I have two mismatched panels, same Watts (100 each) & same Nominal voltage (12V) though the Vmp/Imp/Voc/Isc are slightly different.
    Panel 1) Voc 20V Vmp 16v Isc 6.45A Imp 6.25A
    Panel 2) Voc 22.5V Vmp 18.9V Isc 5.74A Imp 5.29A.
    The difference is small but wanted an expert opinion as I'm new to solar.
    Based on your videos if I have an MPPT controller it seems the best option would be to connect the panels in series so Volts into the MPPT is boosted, the MPPT would lower V out and boost Amps out (12v bank).
    Question: what if i used an PWM type controller? I understand if the panels are in series the whole system must be configured for 24V and if in parallel configured for 12V but which would be the best option? If in series would the system be limited to the lowest Imp? and if in parellel would the system be limited to the lowest Vmp?

    Any help is appreciated!

  • It's all right, not alright

  • Nice explanation…thank you. But the thing that i dont understand is, in series connection, the current should be the lower current of the two sources, whiches 3.08 A, from where we got 8.38 A ?

  • Heard your comment about separate charge controllers for the different panels as an option… how does such an arrangement feed into say a 12v battery bank. I'm a novice.
    Thanks for the very informative videos I do like the way you present the data.

  • hi Amy, These are the best videos on the net. I have a simple question/request. I have three panels going into a 4 battery bank. panels are old and have been in the sun for years. Could you do a video on how to tell what output your getting from panels without a readable sticker. I need to add a or multiple charge controllers. Thanks in advance for your videos.

  • hello altE

    can you please clarify my dought.

    If we connect 4 arrays in single mppt/ inverter with 3 arrays at 15 degre angle and 1 array at 25 degre angle.
    what will be the losses in that. is that effect a lot to system.

    B.K Reddy

  • Thank you for these videos. However, I am not convinced that these are accurate tests; the battery load and capacity status will vary the load factor.. I would think that for accuracy, one would need to use a dummy load at a fixed nominal load (12v in this case), and then use Ohm's Law to determine wattage produced; A(I) x V = W(p,e). Watts, not current is the key.

    I do like that you're testing with MPPT and PWM units as they could vary results; depending on brand, method, component quality, etc. Thx.

  • anyone? can you use a 24 volt 300 watt panel  with a mppt and a 12 volt bank?

  • The series connection makes so much sense !… great video Amy

  • love this!! what is the difference between mppt and pwm charge controllers? does it affect battery charging?

  • Great series on mixing and matching panels! How about a similar topic with batteries? My RV currently has four US Battery US2200XC2 6 Volt 232Ah Batteries wired series/parallel to make a 12 volt bank. Sadly I don't really have room for more RV (Travel Trailer) mounted batteries. I could add some truck or ground batteries for extra capacity, but do they need to be the same? Could I add 12 volt batteries in parallel with a different Ah rating or do they really need to be matched. even if I bought New matching batteries, they will perform different than this bank of much older batteries that I currently have.


  • Hello, I have a 24v 2.4w solar panel. Can I charge 12 v battery?

  • nice explanation but the best way is to buy same specifications solar panel while installing solar pv system.

  • Thank you so much for explaining these things! I've been searching for these answers for months and you're showing me exactly what i need to do for my situation! Best on youtube!!!!!

  • Nad

    still waiting for your mppt with PWM together on same battery bank, Video 🙁

  • i love all of your videos. much more detailed and informative than tbe rest.

  • Excellent and professional demo of set up…loving this "series" you are doing! hahaaa!

  • I'm enjoying leaning from these test rigs and I always have a go at guessing in advance which arrangement will result in the highest MPPT power output. Really educational videos; thanks Amy (and team)!

    I wonder, how does partial shade on one panel affect the overall series performance? If only the voltage drops, not so bad, but if one panel limits the current then it might be worse than if the panels had been wired in parallel.

    The shading test could also look at the differences between partial shading on the low voltage vs. high voltage panels. I'm thinking in parallel, if you knew one panel might be in shade occasionally, you'd make that the higher voltage panel.

Leave a Reply

Your email address will not be published. Required fields are marked *