Higgs

The first one looks like a bona fide MPPT controller, and with a remote. The second one, I'd not trust.

This doesn't give the best information, so I would not speculate on the voltage input here. Perhaps somewhere it says what the controller's limit is. I don't think this controller is top notch. There is a spelling mistake on the face, and the heat sink would make me suspicious of it overheating easily. I'd also gamble on it not being MPPT. MPPT is incorporated into the unit's name, which could lead to an assumption of the capability of such types of product.

There should be a sticker on the back of the panels. And if they don't have diodes, they will be even less efficient, as they maintain a better output when the panel is partially shaded in one area or another.

There is a lot of standard output panels around. I'd guess his 100w panel is no more than 18.6v, 5amps.

The calculations are based on Watts divided by Voltage. 100 watts/18.5v = amps.

The maximum voltage is fairly standard at 18.6v. More with an open, no load, circuit. Delivering about 5amps. Optimal.

Add the voltages up of 4 regular 100w panels and it is still well under the limit of his controller. I run 4x100 on two separate controllers, I'd be happy, if they managed the expected 36 volts from two panels in series.

Most regular 100w panels can, under the right conditions, can produce about 18.6v. You will be well within the limit of the unit.

It also says that your maximum allowed PV input voltage is 150v. That would be impossible, from a 260w panel. I think the extra panel will be ok.

It isn't my cup of tea. Too stark and characterless, even taking into account that is has no personal items knocking around. Some of these ads have presentation problems. 9 photos and non of the workings, for £89,000. ?? It's a boat, not a flat being advertised in an estate agent's window.

Tidy looking, but it's annoying, when they don't think to show the outside.