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Say I have a solar panel setup which can produce a total of 16 kW peak. With an inverter that has a maximum PV input of 6kW, would this be an issue that could lead to defects? Or is it just inefficient, because I would waste (or rather not utilize) 10 kW on hot summer days from the modules? Assume everything else is dimensioned correctly (max string voltage etc.) With my understanding, it shouldn't be a problem, since the inverter will only consume up to its rated maximum power (current) from the modules. I came accross different opinions on this.

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    $\begingroup$ It depends on the inverter design. On larger inverters, there is usually some current protection, but on small, cheap units, you can definitely fry them. On small, cheap installations such as a boat or RV, I try to provide headroom of about X 2 on inverter power. $\endgroup$
    – Phil Sweet
    Commented Feb 5 at 12:17
  • $\begingroup$ @PhilSweet but how? The current isn't getting "pumped" into the inverter. Isn't it only consumed on demand, when there is load connected? $\endgroup$
    – arminb
    Commented Feb 5 at 14:33
  • $\begingroup$ You'll have to read the specs for the controller/inverter. The controller I have to hand is a reasonably high quality, small, unit and has max input current 40A, max panel voltage 100V. It doesn't mention whether it can protect against higher currents (not an issue, I rarely see 25A). $\endgroup$ Commented Feb 5 at 22:13

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Peak / surge current can fry an inverter, as can inductive voltage spikes.

Peak / surge current and inductive spike happen when the inverter input switches -- it's not related to output power value or rating.

A good inverter will be good for its rated panel input. A cheap inverter may not have been designed / tested for input surge or avalanche absorption peaks.

There is nothing wrong or unusual about over-provisioning your solar panels -- it allows you to get full power in off-season, when there is less sun. But inverters are also cheaper now, which allows you to match your inverter to your peak panel input.

You should read your inverter specification for maximum rated panel over-provision, or talk to the inverter manufacturer. If you can't get that information, it's because the information is unknown -- that's why there are different opinions out there -- some unknown inverters are good for lots of over-provision, some are not.

(PWM battery chargers are likely to be more sensitive to overprovision - for PWM battery chargers 10% overprovision is a better guess than 2*)

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