Aiko solar panels review, from an installer

Why ordinary panels handle shade badly

To understand why this panel matters you need to know how a normal one fails.

A conventional solar panel is wired as three sections, and each section is protected by a bypass diode. The diode exists to stop a shaded cell being driven backwards and cooking itself, which is a real danger, so it is not a design flaw.

But it is a blunt instrument. When shade falls on the panel and the diode activates, it switches out the entire section. A shadow covering one cell can therefore cost you about a third of that panel's output, not a thirtieth.

Worse, panels in a string interact. One badly shaded panel drags on the others around it, so the loss on a partly shaded array is routinely far larger than the shaded area would suggest. This is why people are surprised: a small shadow, a big bill.

What Aiko does differently

Aiko's Neostar uses ABC cells, which stands for All Back Contact. The electrical contacts sit on the rear of the cell rather than on the front, which is why the panel has no visible busbars and is part of why it looks the way it does.

Putting the contacts on the back has a second consequence, and this is the one that matters here. Aiko's own technical material explains that a shaded ABC cell enters a non destructive state called semiconductor breakdown, allowing it to pass current around itself. The cell effectively steps aside on its own, and the cells around it keep working.

The numbers Aiko publish are the point: shading one cell results in only single digit percentage power loss, and the bypass diode does not activate until four cells are shaded. Compare that with a conventional module, where Aiko note the diode activation costs one third of the module's maximum power.

So the difference is not that Aiko panels ignore shade. It is that the response is proportionate. A small shadow costs you a small amount, instead of triggering an all or nothing switch.

Aiko state this behaviour requires back contact cells and their interdigitated contact design, because it depends on the cell tolerating a lower reverse bias voltage. That is consistent with why no ordinary front contact panel does it.

What it replaces: the optimiser question

The conventional fix for a shaded roof is to add optimisers, a small electronic device fitted behind each panel that manages it independently so one shaded module stops dragging on the rest.

Optimisers work. But they have costs that do not show up on the quote as clearly as they should.

They are more hardware on the roof. Every optimiser is another device, another pair of connections, and another thing sitting in Queensland heat and weather for twenty five years. Roof mounted electronics are not where failures are convenient to find or cheap to fix.

They add cost per panel, so the more panels you have the more the fix costs.

And they can add a dependency, because some optimiser systems tie you to a particular inverter brand for the life of the system.

A panel that handles shade in the cell removes that decision. Fewer parts on the roof, fewer connections, nothing extra to fail, and no tie to an inverter brand. On a shaded roof that is a genuinely different proposition, and it is the reason we added the panel rather than simply quoting optimisers as we would have before.

I would still put optimisers on a roof where they are the right answer. I would just rather not need them.

The temperature number worth knowing

There is a second specification on this panel that deserves attention in Queensland, and it has nothing to do with shade.

Panels lose output as they heat up, and the figure that describes how much is the temperature coefficient of Pmax. On the Neostar 3S54 it is -0.26% per degree C.

Lower is better, and that number is better than most panels on the market, which typically sit around -0.29% to -0.30%. On a dark Queensland roof in February, where the module runs far above the 25 degrees its rating is measured at, that difference shows up in real generation on exactly the days you want the air conditioning running.

It is not a headline feature and nobody sells it hard. It is the sort of thing that quietly makes a panel better than its nameplate suggests.

The rest of the specification

The panel we install is the Neostar 3S54, model AIKO-A475-MCE54Mb: 475W, 108 cells, all black, with a 30mm black anodised frame and 3.2mm tempered front glass.

The warranty is 25 years on the product and 30 years on performance, with no more than 1% loss in the first year and no more than 0.35% a year after that, which puts the guaranteed floor at 88.85% of nameplate at year 30. For comparison, the Tindo's floor is 87.4% at year 25.

It is 21.1 kg, 2.4 kg lighter than the Tindo. That sounds trivial and it is not when you are carrying modules up a two storey ladder all day.

It carries IEC 61701 salt mist corrosion and IEC 62716 ammonia corrosion testing, which is worth having on this coast, and it is hail tested to 25mm hail at 23 m/s with a 5400Pa front load rating. The junction box is IP68 with the three bypass diodes described above, on original MC4-EVO2A connectors.

Where it suits, and where it does not

It suits you if there is real shade on your roof: a tree that is not coming down, a chimney, a vent stack, a gable, a neighbour's second storey. That is the case it was chosen for, and on those roofs it is the panel I would reach for first.

It suits you if you like the idea of fewer electronics on the roof. Solving shade in the cell rather than with a device behind every panel is a simpler system, and simpler systems age better.

It suits you less if your roof has no shade at all. There is no shade problem to solve, and an open roof is the job of the Trina Vertex S+, the panel we install as standard. Each of our three panels has its own job, and we will not put a shade panel on a roof that does not need one.

It will not rescue a roof that sits in shade most of the day. No panel will. If that is your roof we will tell you from your photos rather than sell you a system that cannot earn its keep.

It suits you less if buying Australian made matters most to you. That is the Tindo, built in South Australia.

One honest note on the frame. At 30mm it is the standard frame, not the heavier 35mm on the Tindo. On a very exposed roof, or one in cyclone country, that difference is worth weighing, and it is a fair trade to discuss rather than something I would gloss over.

The full specification sits on our Aiko solar panels page, and how long solar panels actually last explains what those warranty percentages mean in practice.

Common questions