Controller - Solar Max Power Rating...I'm so confused??

[gillsimo]

Not easy to have to admit but despite plenty of research over many a month now, I'm still barely any the wiser re solar systems.
So...keeping it simple, for my own benefit at least...
I have three 170W panels in series....connected to a Epever Tracer 2210AN controller (20A/100v)....to two 12V/200aH batteries in parallel.
It works so far as my ignorance can tell....I rarely place any load on the system bar a few low wattage led lights for an hour or two over a month so the batteries are constantly charged...nothing has burnt out...the 20A trip fuses have never tripped, so a big sigh of relieve & happy days for a numpty!
But....is this set-up actually ok, like for sure, 'cos I really haven't a clue beyond ` Don't breathe/move...it's working`
My one brain cell has managed to grasp that my three panels in series gives a correct reading of 71V at the controller & that 100V is the max allowed but what is this `solar output max power` quoted for this controller please....260W at 12v?
I'm kinda freaking out because I've got three 170W panels in series, suggesting to me a figure of 510W...way over the 260W.
As everything works then I have to assume that whatever this max input power is...it's not what I'm thinking it is?
Any simple enlightenment would be very much appreciated please.
Gill

 

[Mattb4]

You are over paneled. This is not necessarily a problem. Your controller rating is 20 amp. This means that it outputs a maximum of 20a to charge the batteries. 20a X 13v = 260w (W=VA) This is the amount you will pull from your 510w worth of panels. In good conditions sun wise you are not using their full potential 510w/13v= ~40a

Your panels also have ratings for voltage and amperage. The Voc (Volts open cell) is particularly important because your SCC (Solar charge controller) is easily damaged if you exceed its max PV voltage rating. Since your panels are wired in series you add up all the Voc for each panel. Example: One panel Voc=25vDC thus 3 in series is 75vDC
Yours are what they are and as you report you are getting 71vDC to the SCC. If this is below max voltage by 10-15% you are good. Though you may be better off at a voltage closer to 1.5 to 2 times battery voltage.

When you are over paneled you can gain production during lower light conditions that may make up for the fact you are not using the potential of the panels in full light conditions. The major concern can be that extended charging time at the max of your SCC can be harmful. Not all of these devices are built to run full out for long hours.

ETA: BTW with real small amount of loads you could end up in the situation that you are not sufficiently cycling your batteries. Every now and than a good discharge and recharge helps knock off the chemical cobwebs.

 

[gillsimo]

Many thanks for your detailed reply...very much appreciated.
Apologies also for my apparent ignorance in responding....I fell quite ill within hours of posting this request for help & have only now recovered enough.

 

[740GLE]

That and knowing that panel “name plate rating” is never achieved in real world applications, I wouldn’t consider any issues with your set up.

Sounds like you just need more load to capture the possible Whr the system can generate.

 

[gillsimo]

I'm actually intending to transfer this set up to a bus conversion that I'm about to start.
This will be static & hopefully lived in 24/7....so `more load` is guaranteed.
So...I've no means of assessing if this will be adequate for my needs. Lacking the knowledge means that my only option is to just wait & see.
That said, then needing more load suggests good in terms of adequacy & not using panel full potential suggest bad.
All I'm really wanting/trying to achieve is some expectation of what I'm likely to see, without having to wait.
Perhaps, if I give a rough idea of the needs, then someone might be able to assist?
The bus has a 3Kw/12v Inverter (an overkill I appreciate) that will serve a small 80W freezer regulated to fridge temp....bar this, a small led monitor/Xbox/laptop & small powered speakers (on average, around 4hr per day for each) & chargers for cordless tools occasionally.
12v will supply half a dozen or so led lights, a few 5V usb's, two water pumps for basin/shower...none of these things constantly/prolonged of course.
And I'd add 30% to all of that, 'cos I'm bound to have forgotten a good few needs....a fan or two in the summer immediately springs to mind for instance.
Should I expect to see, no problem, no chance or somewhere in between please?
If improvement is required then where best please?