Fact check: Do All-in-ones burn off unused PV power as heat?

The fellow behind the counter at a solar store gave me some good advice, but stated a few things on which I'd like to get a second opinion. Here's one: The MPP Solar Hybrid LVX 6048 all-in-one inverter will waste excess power coming from the solar panels by burning it off as heat.

Is that true? Or will the all-in-one just refuse to accept excess power which it can't feed to a load, and so cause the solar panels (not the inverter) to waste the power as heat (like this thread thinks - https://diysolarforum.com/threads/panels-and-inverters-voltage-or-current-sources.24880/)?

I call false on this. No solar controller will create and shed excess solar power as heat. Same for the all-in-ones and the rest. They just do not have that function or the ability to dissipate that much heat. Where would 1000+ watts of heat go?

timblack1 said:

The MPP Solar Hybrid LVX 6048 all-in-one inverter will waste excess power coming from the solar panels by burning it off as heat.

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You should have asked him if it wastes all the excess power from the grid by burning that off as heat too.

timblack1 said:

Is that true?

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No.

It's an inverter, not a heater. It only draws the power from the PV array that it needs to supply to the connected loads. If there is zero load (aside from the little bit of power the inverter itself needs to stay operating and monitor the status of the array), then there is all but zero current flowing in from the PV panels.

if panels don't convert the incident radiation into electrical energy, then instead they will heat up a bit (just like leaving anything in the sun does) and eventually reach a thermal equilibrium as they will also dissipate heat to the surrounding air.

timblack1 said:

Or will the all-in-one just refuse to accept excess power

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This. The power drawn from the PV array is only as much for which there are loads to feed, up to the maximal output capacity of the array in those light and environmental conditions.

If an inverter attempted to dissipate heat equivalent to the energy potential of a 5-6kW array, it would melt/catch fire.

timblack1 said:

The fellow behind the counter at a solar store gave me some good advice

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The above is such egregiously bad information it suggests they have little understanding of what they are selling.

Just ask the guy if he has only 100W lamp plug into the AC outlet that can supply up to 1800W (typical US home) of power, will he be wasting 1700W of power?
I wonder where these fellows get the info from?

Those inverters do have a high "no-load" current and are also running fans all the time to help dissipate heat from the inefficiencies and compact size.. maybe that is what was meant?

rhino said:

maybe that is what was meant?

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I doubt it. He said "inverter will waste excess power coming from the solar panels by burning it off as heat".

Most likely meant that if the inverter is 96% efficient - the 4% energy is “lost” as heat internally within the unit.

A 10kw inverter running at full load produces significant heat - i keep mine in a climate controlled enclosure.

Just guessing here, but maybe he meant that it "could" burn off extra power (by connecting a diversion load, such as a water heater or an air heater).

I think many of you are too kind in your interpretation. I think he has a fundamental misunderstanding of electricity. Current is on demand. Pulled, not pushed. Should be flipping burgers, not selling electronic equipment.

TomC4306 said:

I think many of you are too kind in your interpretation. I think he has a fundamental misunderstanding of electricity. Current is on demand. Pulled, not pushed. Should be flipping burgers, not selling electronic equipment.

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Ya, the other thread has idiocy from the same source.

Don’t go to that store. Ever. Again.

12VoltInstalls said:

Ya, the other thread has idiocy from the same source.

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Not entirely sure this 'fellow behind the counter' actually exists.

Rider said:

Not entirely sure this 'fellow behind the counter' actually exists.

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He does exist. He was right to caution me that I needed to be sure the all in one has adequate ventilation to dissipate the heat it will produce; I think that was the main point he was making.

Regardless, you either need to shop at another store with more knowledgeable sales people, or just stop listening to this guy. Fool me once, shame on you . . . . fool me twice, shame on ME - Because I had fair warning you weren't very smart!

Don

Such righteous indignation. I see a vast number of this board giving wrong answers on a variety of subjects. We don't know what he said, only what was thought to be said. And to a question he thought he heard.

my SPF3000TL (48v) growatt does NOT burn off extra solar via heat. THe MPPT SCC that these units have simply "turn off" the pannels when the battery is full and load is low.