Francesfree, I own and use two Blue Sky 3024i with a ProRemote(S). Blue Sky Energy makes top notch products and has fantastic customer service. If you go with Blue Sky, you will be getting some of the best equipment made today. Some may argue that other controllers are better, and they would not necessarily be wrong, but no one will say they are anything but top notch. If you are learning and need help, you will not find a better company to deal with.
How are you planning to wire in the four or five panels? If they will all be in parallel, the 3024i can handle that by itself, but that will be too many amps for the wire. You can run two panels and be comfortable with the amps. Any more and you would need very short wires to handle the amps. If you wire two panels in series, then wire those in parallel, the 3024i can still handle that and the wire will be able to handle the amps (The 3000i would not). But then you are stuck at four panels. You could add another controller later, though, then add another panel.
Adding another networked controller is nice because you can add any kind of solar panel. Matching panels is a non-issue. Technology marches on and you will begin to have trouble finding a panels that match your old panel(s). Panels fade over time, too, so no matter what, they won't match.
I had made a mistake of getting only one controller for two, 285 watt, 60 cell panels. Ended up getting another controller so each panel now has its own controller; that has allowed me to use all of the available power the panels provide. It has been a big help. I also have room for growth.
In the future I am considering replacing my panels with four, 180 watt, 36 cell panels. I would wire two in series to make in effect one 72 cell panel. Then each pair of panels would go to their respective controllers. The 3000i wouldn't be big enough to handle that; only the 3024i could. I considered getting smaller controllers and having 4 controllers, each with one panel, but that starts taking up space inside and creates more holes in the trailer.
Keep in mind you can network only ONE 3000i because it can ONLY be a master. It CANNOT be a slave. In a networked system, one is the master with the rest of them slaves. Therefore, in the future, if you want larger panels or want to connect panels, whether parallel or series, you will need a controller that can handle the power. The 3024i right now is your only option. With the increase in power from solar panels, I suspect Blue Sky will eventually release a controller that can handle more powerful panels, but that doesn't exist yet.
Another thing to consider is if you want to wall mount the 3000i, you will need a box, which then brings the price close to the 3024i that doesn't need a box to wall mount. The 3000i is flush mount without the wall mount box option. The 3024i is wall mount only.
The Midnite Kid, which also can be networked, is an appealing option. It doesn't need a separate remote panel to get detailed information and ability to fine tune your settings like the Blue Sky systems needs. Two Midnite Kids cost $600. One 3000i, one 3024i, and one ProRemote(S) costs $700. You don't need the ProRemote, not even to be networked. If you opted to get the 3000i and the 3024i by themselves, you are looking at $490. The Midnite can handle higher voltages, but can handle only 30 amps. The 3024i can handle 40 amps, but less voltage. The Midnite Kid also has fuses built in, which is quite convenient. I started out with one controller then added the rest a year later. I recommend the ability to fine tune your charging parameters with a control panel of some sort, but it is a lot to learn at first.
A side note: A battery temperature sensor really ought to be used when charging AGMs.
Blue Sky Energy is specifically designed for the RV industry. Many of the other companies started out with home solar; that's probably why you see much higher voltage capabilities. The altestore is the cheapest place I've found for controllers. You may want to check out their 330 watt, 96 cell solar panel made by Panasonic. Blue Sky wouldn't be able to handle that panel, but the Kid easily could.
You are smart in getting a higher end controller that has more safety features built in. For example: If you hook up your solar panels backwards (which can be easy to do because both the positive and negative wires from the solar panels are almost always black and can be easily confused) you can fry some controllers. Both Blue Sky and Midnite are reverse polarity protected. Handybobsolar has some good information. He doesn't approve of the Midnite brand at all. With controllers you get what you pay for.
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