Clipping

[Sparky7]

I just came across a YouTube video on clipping. I've never heard of it before. It may not be an issue for me but I'm looking for advice.

What are my options and is it worth it?

I have a magnum 4400 w inverter and 8910 w of solar panels. The main reason for so many panels is to get more power during the cloudy winter months (NE U.S.).

Thank you

 

[Rednecktek]

Don't worry about clipping, it's not a bad thing per se. It just means that if you're generating more power than your SCC can handle, it'll just max out what you can feed the system.

In worse weather it lets you harvest more power in krappier conditions. No worries.

As long as you're not putting in too much voltage nothing should cause any issues.

If clipping is a major concern, you can always get another SCC and move some panels over to it.

 

[MisterSandals]

I have a magnum 4400 w inverter and 8910 w of solar panels.

What solar charge controller (SCC) do you have?
What panels does your array consist of, how is it configured and what are the panel specs (watts, Voc and Isc)?

 

[MrM1]

When applied to Solar panels and charge controllers, the term Clipping is used to describe what happens to excess power as a result of being Over Paneled. The power the system cannot use is "clipped"

Here is the forums guide on which solar charge controllers can be safely over paneled

Overview of Over-paneling an MPPT controller

To get to the paper, click on the orange button at the top of the screen. There is a misconception that putting more panels on an MPPT controller than the controller is able to use will damage the controller. However, in almost all cases it is...

diysolarforum.com

 

[MrM1]

Over paneling is worth it in small amounts if the charger can handle it.

Growatt is pretty specific from my understanding. 3500w per pv input on the Growatt 12kW is pretty much max as stated in the manual.

Midnite solar is very forgiving. I have a Single classic 150 that was "maxed" out in usable array size (according to their sizing tool ) at 2500w. I double that array size to 5000w and the single classic made more power in mornings afternoons and cloudy days, but it ran (charged) pretty much full Amps most of the day on sunny days . It built up a lot of heat

I recently added a 2nd classic 150. The 2 classics run much cooler, and obviously I generate a lot more power now because I can take advantage of the full 5000w array ... No Clipping.

So over paneling can be worth it in small amounts (if the charger can Handle it) , but when you add double the amount that can b used, you're wasting money on too many panels because all that excess gets clipped.

 

[SpongeboB Sinewave]

Clipping = output current limiting

OR Clipping = maxed out

The term I'm pretty sure comes from the audio/hi-fi industry which means the amplifier is putting out all of the voltage it can supply.

That's all it is.

boB

 

[Ampster]

This issue with clipping when viewed as a flat top of a typical production curve, is that it is viewed as a loss. Unlike the audio examples other less visible things may be happening from over paneling as well that may be compensating. Earlier production in the morning and later production in the afternoons may also be occurring.

 

[fromport]

My fronius primo 3.8kW was clipping today:


It doesn't generate more than 3832 watt of what is specified as 3800 watt inverter.
In the summer when the temperature of the panels go up, the PV power will go down.

 

[Mattb4]

I dislike the word clipping used to describe a SCC max output current effect on the load on solar panels. You do not say you are clipping speed from your car when you drive it at less than full out. You do not say you are clipping the output of a gas generator when you only load it to 50%. You do not say you are clipping grid output at your home when the only thing running is a light bulb.

Solar panels only have watt output when they are loaded.

 

[Danke]

I dislike the word clipping used to describe a SCC max output current effect on the load on solar panels. You do say you are clipping speed from your car when you drive it at less than full out. You do not say you are clipping the output of a gas generator when you only load it to 50%. You do not say you are clipping grid output at your home when the only thing running is a light bulb.

Solar panels only have watt output when they are loaded.

So as long as you keep the voltage in the inverter range, there is no worry about “clipping” doing any damage?

 

[Mattb4]

So as long as you keep the voltage in the inverter range, there is no worry about “clipping” doing any damage?

There is some concern based on duty cycle of the SCC. Not all SCC can handle being driven full out for long periods of time. Unfortunately SCC manufacturers do no list a duty cycle for their units.

 

[MrM1]

So as long as you keep the voltage in the inverter range, there is no worry about “clipping” doing any damage?

Not sure that's always true (and assume u mean SCc range or at least least the SCC of an All In One) . My understanding (I didn't want to try it) was if you over panel a Growatt too much , even though you were keep the DC voltage under the SCCs VOC max input, you'll get white smoke. I didn't want to test the wisdom, so I just decided to add a second charge controller to that system

I would suggest reading the guide I linked above, @FilterGuy went to greatly lengths to detail the process and SCCs that can and can't take it.

Overview of Over-paneling an MPPT controller

To get to the paper, click on the orange button at the top of the screen. There is a misconception that putting more panels on an MPPT controller than the controller is able to use will damage the controller. However, in almost all cases it is...

diysolarforum.com

 

[FilterGuy]

Definitely pay attention to the manufacturers recommend limits. A lot of the value priced inverters can be bricked with too much over paneling

 

[Sparky7]

Don't worry about clipping, it's not a bad thing per se. It just means that if you're generating more power than your SCC can handle, it'll just max out what you can feed the system.

In worse weather it lets you harvest more power in krappier conditions. No worries.

As long as you're not putting in too much voltage nothing should cause any issues.

If clipping is a major concern, you can always get another SCC and move some panels over to it.

Is SCC the charge controller?

 

[FilterGuy]

Is SCC the charge controller?

yes. SCC = Solar Charge Controller

 

[SpongeboB Sinewave]

As long as the charger or inverter is UL/ETL or otherwise NRTL "listed" (tested/approved) they will be tested for full output until at least they are temperature stable and lower than a certain temperature. Then another test or two are done.

Doesn't mean their life will not be reduced a bit if they run balls out every day but you over-panel because there are days when there are clouds and lower power than normal. If you're doing this every single day in and day out, then a second charger or inverter it probably a good idea.
Heat can slowly kill but should be OK. For a SCC/MPPT higher input voltage when running full power will generally heat the units up more for the same output power.

So if you can wire the unit for more power but less input voltage but reducing the number of PV in series and maybe parallel a string or two, the voltage will be lower and when it clips, it should run a bit cooler than with the higher voltage with same power of PV connected

There is another word used beside clipping... Flat topping. These refer to the output being limited like in the graph that was shown. Not the input.

boB

 

[Sparky7]

Don't worry about clipping, it's not a bad thing per se. It just means that if you're generating more power than your SCC can handle, it'll just max out what you can feed the system.

In worse weather it lets you harvest more power in krappier conditions. No worries.

As long as you're not putting in too much voltage nothing should cause any issues.

If clipping is a major concern, you can always get another SCC and move some panels over to it.

Ok I understand what you meant scc (solar charge Controler). I thought the guy in the video was talking about the inverter being too small. Maybe he misspoke or I misunderstood. My cc are sized properly to the panels. I have two midnight classics. One is a 150 and the other is a 150s.

 

[FilterGuy]

For MPPT controlers,

1. The first thing to look at is the max Array Voc (Adjusted for cold temperatures). If you go above the max specified by the controller you are likely to burn out the controller.
2. Then look at min start up Voltage. (Some MPPT controllers will not start working till the voltage is fairly high).
3. The next thing to check is overpaneling. Different controllers will specify this differently, but it will usually be either a max Array wattage *or* Max Array Isc.
   Note: I recommend staying withing the over-paneling limit of the controller However, If you have panels facing different directions (like East and West), you might be able to do more over-paneling, but I don't know a way of quantifying it

 

[Sparky7]

I have two midnight classic cc. They were sized by the company I bought most of my equipment from so I believe they are good (maxt out though at full sun).

So this doesn't (clipping) have anything to do with my inverter size?

 

[Rednecktek]

Nope, the clipping is on the SCC, the inverter doesn't care about how much your panels are producing, just that there's enough voltage in the battery to run.

Oh, and we call the 180mph speed limiter in sports cars clipping as well.

The More You Know! ?