To clarify, the Eco-Worthy 20a MPPT controller works well, but it does have a rated 42v Voc input limit, which should mean it can only do one 24v panel at a time, and cannot do two 12s (22v each)
Somebody is getting away with running two 12s in series and it did not eat the controller, but I don't know if that can be expected or is a fluke.
My Eco-W and 230w panel combo performs according to ambient temp which also affects panel temp very much. This is normal for MPPT and you get fewer amps to the battery when it is hot out.
The panel gets Isc whether hot or not, same as a 12v panel does. The difference with PWM and 12s is that you keep getting that Isc to the batteries even when it is hot out, but with the MPPT you have a different action, where now you get your amps dependent on voltage which drops in the heat, so
When cool out, I get 15.5a with MPPT compared with 14.5a PWM, but
when hot out, I get 13.5 with the MPPT instead of 14.5. (as observed at different times on average)
So I like to get the "expected amps" all the time and it seems to be hot out when it is nice out, which is when solar works, so generally speaking I would prefer PWM for when and where we camp and not MPPT.
That means if I have a choice of 12v or 24v and want 240w, I would take two 120s and PWM over a single 240 and MPPT every time. Except if there is some very good reason (money, roof space) to take the single 240 instead of the two 120s.
I found the cheap $15 ebay 20amp controller I had works very well but has no adjustable set points. For $35 I found the Solar30 controller to be superb. It has 30 amps so it can do more panel wattage, it has adjustable absorb and float voltages, and it has a built in ammeter--very neat feature!
The Eco-W MPPT has adjustable float and absorb voltages too and is proving to be trouble free as reported by JiminDenver a couple years ago.
It is hard to recommend any combo of panel/controller when panel prices are so different all over the map and where shipping can be a killer if you can't pick them up yourself from the factory outlet. ( a solar dealer has to pay shipping, so that means you do too if you buy there)
It is horrifying still to see otherwise reputable general hardware/auto stores selling little solar kits or portables for horrendous prices like $300 for a 60watt job ($5 a watt!) when a real solar place here sells 12v panels for $2 a watt. You can sometimes find better prices than that too. You have to feel sorry for all those people who are buying those things, but the worst is any local RV dealer's store, where they want say $700 for a 140w panel plus some stuff worth maybe $50 in a kit, and at least that much more to install it for you!! But people are going for that. Amazing.
