Replacing the panels on my RV which have failed. Setup has two MPPT 100/30 and originally was (8) 100W panels, 4 to each controller wired series/parallel. Replacing panels with (4) 200 W which have 31.1 V max, 6.43A and 36.4 open V. Was just going with 4 and keeping the series wiring but just realized I have room for one more, so I could run 3 to one of the controllers but am not sure if it’s a good idea or not. I would have to run one set parallel since the voltage would exceed the controller capacity and the other in series, but wasn’t sure if it would work out with them running separately or if the increased amps would be an issue. Would appreciate any feedback.
I guess I should’ve phrased my question a little different. I know I can run the panels, my question really is, if I run one controller with the 2 panels in series and the other with the 3 in parallel is that an issue since ultimately the two outputs terminate at the same place.
3 in series will go over the 100v max in cold temps. So not a good idea.
Each string in parallel would need to match in voc. So a 3 and a 2 are not an option anyway.
You could to 3 in parallel 3x 6.43 if that is isc will be under the max for the 100/30.
But if your system is 24v it may be a problem for charging well.
If 12V then 3x200W panels in parallel would exceed the MPPT 100/30 capacity as it has potential to exceed 30A on output.
3 panels in series x 36.4Voc exceeds 100V input so that’s not viable.
Since you have 2x MPPT 100/30 it seems 2 panels in series to each MPPT is the most practical setup. Will not reach 100V pv input and will not exceed 30A output (each) to a 24V or 48V system.
If you are feeding a 12V system then 400W of panels per charger is a bit much for MPPTs limited to 30A output.
Battery system is 12V, as posted i am aware that 3 in series would exceed the capacity of the controller, was looking for feedback on whether running 2 in series on one controller and 3 parallel on the other was feasible or desirable.
This is not the issue, as the controller will internally limit to 30A. However the input max current must be respected. Some over paneling (Having excess power available) on the input is usually a good idea, as then performance can be maintained in cloudy weather.
As long as you are within the capabilities of each MPPT you can set up the individual solar arrays however you want. Am I missing something here @lxonline ? Seams like a pretty simple set up.
I don’t understand. If one MPPT has 2 panels operating at one voltage and another MPPT has 3 at a different voltage and both MPPTs are connected to the same battery bank what does it matter? Both will track maximum power for their panels and both with reduce the voltage according to the battery’s requirements properly assuming they are set up with the same charge parameters. This kind of thing that he is asking is done all the time.
I was covering bases in case the OP meant one more panel. Not one more string of 2 more panels. Sometimes people mean one thing but type something that can be understood a different way.
Which is also why the mppt calculator link was added, so they can then run the scenarios themselves and see.
@ TherealKT, Thanks for the reply. As you can see from the responses here I was told by many that I could not have mismatched panel arrays or run one set in series and the other parallel, but as you had stated, I thought the controller would take the input regardless and adjust to proper output. Just wanted some confirmation to clear the dust of so many differing opinions.
Mixing different panels on the same MPPT is not recommended. It does work, the MPPT does not care (apart from surpassing max input voltage) but its not optimal, you might only get 3/4 or half of the rated panel output, or not get a stable power output since theres no uniform MPP to track.
Same goes for alignment, the panels of one MPPT should all be aligned the same, if not then performance will be lower.
Putting one type of panel onto one MPPT and another type onto its own is not mixing , its just two seperate systems.
There might be some naming conventionas to what is a string and what is an array, but im sure people coming from different regions does not help
Thanks, yeah I am not mixing on the same system, just running one system with 2 series panels and one with 3 parallel panels. I was told not to do this by several people but could not understand why when they are completely separate and the output will be adjusted accordingly by each controller.