Inverter Monitor
Dealing with clipping
What is clipping?
It is not uncommon for the total power of Solar Panels installed to exceed the power rating of the Inverter to which they are attached. This means that there is more generation on dull days, without incurring the extra expense of a more powerful Inverter.
However at peak times on sunny days, the generation might be limited. This loss of generation is known as clipping and if you have a hybrid battery system, you can reduce the clipping by controlling the charging of the battery.
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The image shows what can happen if the battery is simply left to charge from the solar generation. By around 11am, the battery is full, and from that point on generation is clipped and the curve has a flat top.
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If you want every last watt of power from your solar investment, try this method to take control of clipping.
Three simple entries in the schedule
When a sunny day is expected, it can be better to export the early energy, saving the battery for later. Only start charging the battery just before the generation reaches the capacity of the Inverter. To do this set the charge rate to zero before sunrise, in this example 5am.
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Estimate the time when the clipping would start; this will vary with time of year so no need to be precise. If it's around 10:30, set the battery to start charging at 10:15. Estimate the time when clipping would end, and set a charge rate so the battery reaches full around that time. This is best done by trail and error, but if you are able to check the app at 10:15, use the battery bar on the main screen to see the forecast of when the battery will become full.
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Finally if you have a cheap overnight tariff that you use to charge the battery, set the charge rate back to whatever is needed for the overnight charging.
Tip: In the app you can use battery above 0% to mean an action should always be done.
Perfect Results
Check the graphs to see how successful your strategy has been. It may take a few attempts and adjustments until you reach the best settings.
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In this example, using the Octopus Flux tariff, there is some cheap rate EV charging, then a bit of battery charging just to get through to sunrise. By controlling the charging of the battery, clipping has been totally eliminated, and a full charge reached just in time to benefit from the peak export rate.
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This image has all the options turned on, so you can see the power, voltage, and current for all the energy flows in one graph. Compare to the image at the top of the page, where the home consumption was turned off to focus on the generation and export in relation to the battery.