How to Wire Different Sizes of Camper Solar Panels Together - Effects of Mismatched Solar Panels

hey everybody it's nate from explores.life i teach people how to build diy campers and in this video i will teach you what happens when different sizes or brands of solar panels get wired to each other in the same solar array now this video is episode number 12 in a series of videos where i teach you all the basic electrical skills and concepts you'll need to tackle the next electrical project in your camper now two quick things before we get started number one i'll be going through this information pretty quickly now if you need this information slowed down you can find all the diagrams and the math involved in this video in the accompanying blog post number two i'll also briefly cover the effects that wiring solar panels in series parallel and series parallel has on the array now if you already grasped that concept i've included some time stamps at the bottom of this video where you can skip ahead to the appropriate section as you wish now let's get started so before we talk about mixing solar panel sizes let's have a crash course on how wiring solar panels in parallel versus series affects their voltage and amperage two key points here number one wiring solar panels in series will add their voltages together while their amperages stay the same and number two wiring solar panels in parallel will add their amperages together while their voltages stay the same so let's check out some math in more detail on how this actually works here we see four 100 watt solar panels wired in parallel which means that all of the positive wires are connected together and all the negative wires are connected together and then they go to the charge controller now since wiring solar panels in parallel will add their amperages while their voltages stay the same we would add 5 amps plus 5 amps plus 5 amps plus 5 amps to get a total of 20 amps at 20 volts headed into the charge controller now we installed 400 watts of solar panels and by using watts law of volts times amps equals watts we can see that 20 volts times 20 amps equals 400 watts for 100 array efficiency now this means that of the 400 watts of panels that we installed we can expect to see all 400 watts of power heading into the charge controller under ideal conditions in this next example we see four 100 watt solar panels same as before except this time they're wired in series which means that the positives and the negatives of neighboring panels are wired together with the positives and negatives of the end panels going to the charge controller since wiring solar panels in series will add their voltages while their amperages stay the same we would add 20 volts plus 20 volts plus 20 volts plus 20 volts to get a total array voltage of 80 volts and 5 amps heading into the charge controller now we installed 400 watts of solar panels and by using watts law of volts times amps equals watts we can see that 80 volts times 5 amps equals 400 watts for 100 array efficiency this means that of the 400 watts of panels installed we can expect to see all 400 watts of power heading into the charge controller under ideal conditions now in this example it's the same four 100 watt solar panels shown as before except this time they are wired in series parallel in this array pairs of panels wired in series with the two resulting series strings are wired in parallel since solar panels wired in series adds their voltages together while their amperages stay the same we would add 20 volts plus 20 volts which gives us 40 volts and 5 amps for each of the two series strings since series strings wired in parallel adds their amperages together while their voltages stay the same we would add 5 amps plus 5 amps for a total of 10 amps at 40 volts heading to the charge controller now we installed 400 watts of solar panels and by using watts law of volts times amps equals watts we can see that 40 volts times 10 amps equals 400 watts for 100 array efficiency this means yet again that of the 400 watts of panels installed we can expect to see all 400 watts of power heading into the charge controller under ideal conditions so now that we have our solar panel array basics covered let's talk about wiring different sizes of solar panels into the same array for this first example we have two 200 watt solar panels and two 100 watt solar panels the two 100 watt solar panels are operating at 20 volts and 5 amps while the 200 watt solar panels are operating at 25 volts and 8 amps now if we were to wire all of these panels in parallel solar panels wired in parallel as their amperages while their voltages stay the same this means that we would add 8 amps plus 8 amps plus 5 amps plus 5 amps for a total of 26 amps heading to the charge controller now although the volts stay the same in a parallel wired array since we have different panel voltages we must use the lowest common denominator which is 20 volts so we have 20 volts at 26 amps heading to the charge controller now we installed 600 watts of solar panels and by using watts law of volts times amps equals watts we can see that 20 volts times 26 amps equals 520 watts for only 86 array efficiency so this means that of the 600 watts of panels installed we can expect to see only 520 watts of power heading into the charge controller under ideal conditions for this next example we have the same two 200 watt solar panels and two 100 watt solar panels the two 100 watt solar panels are operating at 20 volts and 5 amps and the 200 watt panels are still operating at 25 volts and 8 amps now if we were to wire all of these panels in series solar panels wired in series adds their voltages while their amperages stay the same so we would add 25 volts plus 25 volts plus 20 volts plus 20 volts to get a total of 90 volts heading to the charge controller now although the amps stay the same in series wired arrays since we have different panel amperages we must use the lowest common denominator which is 5 amps so we have 90 volts at 5 amps heading to the charge controller now we installed 600 watts of solar panels and by using watts law of volts times amps equals watts we can see that 90 volts times 5 amps equals 450 watts for only 75 array efficiency so this means that of the 600 watts of panels installed we can expect to only see 450 watts of power heading into the charge controller under ideal conditions now let's say we were able to find solar panels of different wattages but their voltages are the same or at least really close this array shows mismatched panel sizes of 100 watts and 200 watts but we were able to find panels with similar voltages wiring the similar wattage solar panels in series would yield 40 volts at 10 amps for the 200 watt panels and 40 volts at 5 amps for the 100 watt panels now wiring those two series strings in parallel would yield 40 volts at 15 amps since 10 amps plus 5 amps equals 15 amps and the volts stay the same at 40. now we installed 600 watts of solar panels and by using watts law of volts times amps equals watts we can see that 40 volts times 15 amps equals 600 watts for 100 array efficiency so this means that of the 600 watts of panels installed we can expect to see the full 600 watts of power heading into the charge controller under ideal conditions great so we can just always wire similar panels in series and wire those series strings in parallel right not so fast same solar panels as last time but this time we're going to try to get an 800 watt array by using three 200 watt panels and two 100 watt panels if the three 200 watt solar panels were wired in series and the two 100 watt solar panels were wired in series and then those two series strings were wired in parallel here's how the math would look solar panels wired in series gets their voltages added together while their amperages remain the same so for the 200 watt panels we would add 20 volts plus 20 volts plus 20 volts for a series string total of 60 volts at 10 amps for the series string with the 100 watt panels we would add 20 volts plus 20 volts for a series string total of 40 volts at 5 amps since series strings wired in parallel gets their amperages added together while their voltages remain the same at the lowest common denominator we would add 10 amps plus 5 amps for a total of 15 amps at 40 volts headed to the charge controller now we installed 800 watts of solar panels and by using watts law of volts times amps equals watts we can see that 40 volts times 15 amps equals 600 watts for 75 array efficiency now this means that of the 800 watts of panels we installed we can expect to see only 600 watts of power heading into the charge controller under ideal conditions which means that the two 100 watt panels are effectively useless in this array and by using just the three 200 watt panels in series we could expect the same amount of power output with fewer panels and lower cost and finally and perhaps the most dramatic example this is a specific question from somebody in my diy camper crew private group and i thought it was a great example to bring up on the channel here they had six 200 watt panels wired in a series parallel configuration for a total of 1200 watts of solar with 100 array efficiency everything was perfect but they found they had room for one more panel on their roof and wanted to wire it into the array in parallel with the other series strings now i had to talk them out of it and here's why since series wired solar panels get their voltages added together while their amperages remain the same this means that both of the series strings have a voltage of 51 volts and an amperage of 11.76 amps now solar panels or series strings wired in parallel get their amperages added together while their voltages operate at the lowest common voltage this means that the entire array would operate at 17 volts and 35.28 amps so using watts law of volts times amps equals watts we can see that the maximum amount of watts that we could see out of this system is 600 watts so since they already had 1200 watts of solar in a perfectly configured series parallel configuration to total 1200 watts heading into the charge controller adding an additional panel would actually cut their array output in half so moral of the story unequal solar panels can be used in the same array but proper array planning is critical to avoid array inefficiencies and if array and efficiencies are unavoidable just make sure that you know this ahead of time and account for this in your power audit and once you understand these concepts you can really have some fun mixing and matching solar panels to work around vent fans air conditioners or whatever else you have mounted up on top of your camper and that wraps up this video now in the next video i am going to teach you when you need to versus when you do not need to use fuses in your solar array so hit the notification bell if you want to be notified when that goes live now i hope you found this video helpful and if you did it'd be awesome if you'd share it with somebody or a group who you think could benefit from it and leave this video a thumbs up drop any questions you've got in the comments section below subscribe if you want to see more diy camper building tutorials and i will see you in the next video

Channel: EXPLORIST life - DIY Campers

Views: 50,752

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Keywords: mixing solar panels, mixing solar panels of different wattage, mixing solar panel, mixing solar panels from different manufacturers, mixing solar panel types, mixing solar panel voltages, mixing mono and poly solar panels, mixing different solar panels, mixing wattage of solar panels, camper solar panels, mixing camper solar panel sizes, mixing RV solar panel sizes, Mixing Camper van solar panel sizes, solar panels for rv, solar panels, diy solar

Id: jejro4zkl8I

Length: 12min 19sec (739 seconds)

Published: Sun Nov 15 2020