Well, a couple of questions:
Are you likely to be adding more panels any time soon?
Do you think you may want to add ground panels?
For the two Eclipse panels that you are mounting, and presuming the answers to the above questions are "No, not likely" (of course feel free to change your answer
), this is what I'd choose:
1) I'd run the panels as a series pair, so then I'd be going MPPT. (If you decide to do this, we can talk specific wire gauge vs. voltage drop, but the wires could be smaller since the voltage is higher.)
2) I'd choose either the Morningstar Sunsaver 15 MPPT, or the Blue Sky SB1524ix. We can get into detailed reasons if you like. I agree with you on the Victron. I love their stuff, but with lead-acid batteries I want temperature compensation on them, and you can't get that with the Victron controllers until you get into their very big units (way overkill for us). Boo! And yes, of course this is just one more "thing that won't be a thing" with lithiums, but most of us don't have those now (and they have other "things that are things").
Both of the controllers I mention above have remote temp comp. I like them both for different reasons (and they both have things I don't like, but on balance I'd still use one of the two vs. any others for your setup).
I've been running a Morningstar Sunsaver 15 MPPT for two years now with two 100 watt panels. Even though mine are ground panels (so I can site them advantageously, tilt them, etc.), I've only gotten the "you could have been taking in more than 15 amps except, sorry, the controller limited it" notification a couple of times (in July, on the prairie, in full sun). So for that reason I don't think a 15 amp controller is a limitation. After all, if you needed those extra few amps on those two perfect July days, how would you get by the rest of the year?
Actually, I'm going through this exact same decision process right now for a different project that has two of the same 100 watt panels. And I'm waffling between the same two controllers.
I do have a fondness for the "sturdy goodness" of the Morningstar, with its big heat sink fins, reasonably spaced terminal screws, and high voltage limit (even though I'm not using that now). No glitz, all function. And mine has worked perfectly for two years. Also, I helped a friend install one and it was making a barely detectable whistling noise. I contacted them (this was a year later), and they immediately shipped out a new one, with a tag in the box so we could send back the other one at no cost. No "Are you sure it's whistling?" or "We've never heard this complain before," or "We'll send you a new one once we receive the old one." Just bang and we had a new one. It's warrantied for five years.
What don't I like about it? Mainly that I have to use a Windows computer to program it. Also the remote meter (RM-1) isn't super fancy (it works well, but it doesn't show you multiple things at once, although it's intuitive to scroll through the various items).
On the other hand the Blue Sky has some slick features. The optional IPN Pro remote meter shows two fields at a time, can be used to program the controller, AND has a shunt and works as an amp counter battery meter (vs. a stand alone Victron BMV 700 or the like). It costs more than the Morningstar basic meter (and I already had a Victron BMV 700), but its slick (especially if you still need a battery monitor). Another cool thing is that if you were to add, say, another Blue Sky controller, the meter puts them both together to make them function as one. (The Morningstar would still work "fine" if you had two similar setups, with the same settings, and two Sunsavers; but it doesn't literally make them one controller, like the IPN Pro remote meter does.)
Also, the Blue Sky can use "end amps" to end the absorption time. This is sweet and avoids the figuring for how to set the parameters on the Morningstar (although you don't have to do it very often).
But of course there are some downsides too, as there seemingly can't be one controller with ALL the good features
. The max voltage is lowish (compared to Victron's 100 volts, or Morningstar's 75 volts). And they kind of use tricky terms (like a controller is a 40 amp controller but if you use X panels it's really only a 30 amp --- stuff like that). Not that that matters if you don't need the extra capacity*. And of their array of controllers, the 1524 is one of the higher voltage ones (the reason it's a thing is that with these controllers, if you go over the amp rating (on those two days in July
) they just slough off the extra; but if you go over the volt rating, they die).
Another minor negative (to me) is that it's an aluminum face plate for a heat sink vs. big ol' fins. But again, as long as it stays cool, that's what counts. The terminal screws are also a bit crowded, but that can be worked around. Especially if I didn't already have a battery monitor (or even if I had a Smart Gauge but wanted to add an amp counter), I'd be strongly considering the Blue Sky 1524ix plus the IPN Pro remote/shunt combo. It would also be a bit nicer if you added panels (as long as you stuck to something like pairs of 100 watts).
So, in summary, if it were me (and it kind of was/is since I have a similar setup), I'd run the pair in series, and then run either a Morningstar Sunsaver MPPT 15 with RM-1 remote meter, or a Blue Sky 1524ix with IPN Pro remote meter. A Smart Gauge is a nice addition for reading SOC, but an amp counter meter also has its place (so with the Morningstar I'd go with a Victron BMV, or with the Blue Sky the shunt/IPN Pro remote combo already do that).
If you are running a series pair, then you can still have a junction box on the roof, but you can also just run your single pair of 10AWG wires in through a roof gland (say a pair of right angled ScanStrut DS-H6 glands or a Go Power plate) and then put your switch/junction inside either the upper cabinet forward end or maybe in the overcab. I found that things would be kind of tight if I wanted to put a junction box on the roof (it would either make the panels have to be higher up than I wanted, have to be on the top hump, or in front of the panels - none of which appeal). Plus how convenient to have them "indoors."
I like a simple "on/off" M-series switch from Blue Sea, but there are other options.
If you want to give some input on whether any of this interests you, then if you like we could talk specific wire gauges and runs, etc. As always, these are my opinions (but there are many others of course).
BG
*So the 1524's recommended maximum PV open circuit voltage is 45.6, and the absolute max is 57 volts. So you might think, geez, that's plenty high. And it probably is, but it's slightly close and here is why: In the morning, JUST as the sun is coming up, you can hit higher voltages than you'd think. It's cold out, which makes the voltage higher, and the voltage isn't "working" yet so it's free to ramp up. So for example, let's say it's 15ºF at 6a.m. just as the sun is coming up, and you have your two Eclipse panels. The open circuit voltage rating (VOC) on those is 21.2 volts. Now let's say you are running them as a series pair. So now the VOC is 42.4 volts. Now let's go back to that 15ºF morning (or, brrr, let's not!). At that temperature in the morning, you'd hit 23.24 volts. So in series that would be 46.48. That's still fine on the 1524ix, but it would be a bit too close for comfort on, say, their 25 amp controller (50 volt dead max vs. 57 for the 1524).
Sorry for all the "math" above, but I just wanted to show how a "simple" pair of "12 volt" panels in series can actually get up there in voltage at times. It's just easy to have the 75 or 100 volt maximum of the Morningstar or Victron units. But, even -20ºF with the Eclipses would only be 45.72 volts on that record cold morning, so would still be fine with the 1524ix.
