{"id":21572,"date":"2018-05-24T16:34:16","date_gmt":"2018-05-24T06:04:16","guid":{"rendered":"https:\/\/www.solarquotes.com.au\/blog\/?p=21572"},"modified":"2025-09-30T10:04:22","modified_gmt":"2025-09-30T00:34:22","slug":"half-cut-solar-cells-panels","status":"publish","type":"post","link":"https:\/\/www.solarquotes.com.au\/blog\/half-cut-solar-cells-panels\/","title":{"rendered":"Half Cut, Split-Cell Solar Panels: Higher Efficiency & Better Shade Tolerance"},"content":{"rendered":"
\"half-cut

Don’t let a half-cut solar installer install your half-cut (AKA split-cell) solar panels.<\/p><\/div>\n

Silicon solar cells of the type now used for almost every residential solar installation in Australia have been around for a long time.\u00a0 They are 64 years old.\u00a0 This makes them the same age as nuclear power generation.\u00a0 They’ve come a long way since they were first made at Bell Labs<\/a> in the United States.\u00a0 Originally they were only able to convert around 6% of the energy in sunlight into electrical energy but now the most efficient solar panels on the market manage 22%.<\/p>\n

Unfortunately, the days of large improvements in efficiency have long been over.\u00a0 Now we only see small incremental improvements and one of these in use that will be much more common in the future are panels that use half-cut solar cells. These panels are known as both half-cut and split-cell solar panels.<\/p>\n

Luckily, explaining what half-cut solar cells are doesn’t involve complex scientific explanations involving quantum mechanics.\u00a0 They are literally normal solar cells that have been cut in half.\u00a0 Instead of having 60 solar cells, as most panels put on roofs do, they have 120 half-sized ones.\u00a0 This results in lower electrical resistance that improves efficiency.\u00a0 An additional benefit is half cut panels resist the effects of shade better than standard solar panels.\u00a0 This isn’t directly due to the cells being cut in half but because of the way they are wired together.<\/p>\n

While the increase in efficiency is only small, several large manufacturers are convinced modern production techniques make half-cut solar cell panels worthwhile.\u00a0 At the moment REC Solar<\/a>‘s TwinPeak panels are the only half cut ones widely available in Australia, but with many large manufacturers either starting to produce them or planning to we will soon be spoiled for choice.<\/p>\n

How They Work<\/h2>\n

A conventional solar panel typically contains sixty 0.5V solar cells wired up in series. Voltages add in series, so this example solar panel operates at 30V.<\/p>\n

\"Solar<\/p>\n

If you cut a solar cell in half it will produce half as much current, but its voltage will stay the same.<\/p>\n

You’ll also have twice as many of them so, if half-cut cells were wired together as in a standard panel, they would produce twice the voltage.<\/p>\n

This would not be appreciated by installers using normal solar inverters<\/a> or trying to stay within Australian standards for residential solar voltage.<\/p>\n

\"Half<\/p>\n

To make their voltage similar to standard panels the half-cut cells are wired together differently. There are 2 lots of sixty series-connected cells that operate at 30V each. These two 30V halves are then connected in parallel. Voltages in parallel stay the same, so the panel remains at the standard 30V.<\/p>\n

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Bypass diodes not shown<\/p><\/div>\n

Why are panel manufacturers going to the trouble of cutting cells in half?<\/p>\n

Two main reasons:<\/p>\n

    \n
  • The lower current in each half of the panel means lower resistive losses. This increases the solar panel efficiency<\/a> slightly.<\/li>\n
  • Improved shade tolerance in certain situations.<\/li>\n<\/ul>\n

    Shade Tolerance<\/h2>\n

    A standard solar panel has 3 strings. Thanks to bypass diodes (shown in red below), one small spot of shade on a panel, caused by, say, a leaf or bird poop, will knock one entire cell-string out of action, but not affect the others.<\/p>\n

    Standard panel shade behaviour<\/strong><\/p>\n

    Here’s what happens on a standard solar panel. The current flow is shown in orange, with the bottom bypass diode activated:<\/p>\n

    \"\"<\/p>\n

    Two-thirds of the cells are active, so you get approximately two-thirds of the power.<\/p>\n

    Half-cut panel shade behaviour<\/strong><\/p>\n

    Instead of having 3 cell-strings like a standard solar panel, the half-cut panel has 6 cell strings making it a 6 string<\/a> panel. \u00a0One small spot of shade on a half-cut panel makes things interesting.<\/p>\n

    The current can either go through the bypass diode, in which case, only two-thirds of the cells are active – the same as a conventional panel:<\/p>\n

    \"\"<\/p>\n

    The alternative path for the current is via string (3), avoiding the diode, in which case five-sixths of the cells are still active.<\/p>\n

    \"\"<\/p>\n

    Half-cut shade performance depends on your inverter’s MPPT algorithm:<\/strong><\/p>\n

    You need a good inverter to make the most of half-cut panels. They need to find just the right amount of current and voltage to either activate or not activate the bypass diodes, to get the most power from the particular pattern of shade on the panel at that moment in time.<\/p>\n

    To make the most of a half-cut\/split-cell solar panel’s improved shade tolerance you need to use an inverter with ‘Global Maximum Tracking’ MPPTs, so they don’t get stuck on the wrong power curve maximum. GSES’s excellent new video explains this really well:<\/p>\n