Clipping calculation

[NullSlayer]

Hello all,

I currently have a 7.1kw system which is getting expanded to a 9.3kw system. We are currently running a Solaredge SE6000 and my installer is recommending I keep this invterer. I know I'm going to be clipped and am wondering if there's a fairly simple way to calculate how much I'm going to lose.

My system will be 18 South facing panels, 6 West facing and 6 East facing. All 310W Q-cells. I tried doing some calculations on PVwatts but wasn't sure if my results were any kind of accurate. I live in zip code 23320. (Butch if you see this I appreciate your advice from reddit. I'm already fuming at their response you debunked).

Thanks for any advice.

[ButchDeal]

Hello all,

I currently have a 7.1kw system which is getting expanded to a 9.3kw system. We are currently running a Solaredge SE6000 and my installer is recommending I keep this invterer. I know I'm going to be clipped and am wondering if there's a fairly simple way to calculate how much I'm going to lose.

My system will be 18 South facing panels, 6 West facing and 6 East facing. All 310W Q-cells. I tried doing some calculations on PVwatts but wasn't sure if my results were any kind of accurate. I live in zip code 23320. (Butch if you see this I appreciate your advice from reddit. I'm already fuming at their response you debunked).

Thanks for any advice.

You can get hourly output from pvwatts, and then look for the amounts over 6kw...
you can also model your system as is now to see how close you are getting to actual since it has been running for a little while.

[nwdiver]

Hello all,

I currently have a 7.1kw system which is getting expanded to a 9.3kw system. We are currently running a Solaredge SE6000 and my installer is recommending I keep this invterer. I know I'm going to be clipped and am wondering if there's a fairly simple way to calculate how much I'm going to lose.

My system will be 18 South facing panels, 6 West facing and 6 East facing. All 310W Q-cells. I tried doing some calculations on PVwatts but wasn't sure if my results were any kind of accurate. I live in zip code 23320. (Butch if you see this I appreciate your advice from reddit. I'm already fuming at their response you debunked).

Thanks for any advice.

What region are you located in? Do you have net metering? I expanded a 4.45kW to a 5.7kW system recently and kept the 3.8kW inverter. The customer is losing ~3% this month due to clipping but all panels face south and I expect clipping to be higher in the spring and fall.... BUT Xcel in NM doesn't carry over monthly excess at full retail so the energy lost in the spring and fall when HVAC consumption is lower is worth 75% less.

Kind of interesting... since SMA inverters only clip one MPP channel you have a basis for determining how much energy was ACTUALLY lost due to inverter saturation. So even with an oversize ratio of ~1.5 not all that much clipping... <3%.

Screen Shot 2019-08-27 at 8.50.19 PM.png

[NullSlayer]

What region are you located in? Do you have net metering? I expanded a 4.45kW to a 5.7kW system recently and kept the 3.8kW inverter. The customer is losing ~3% this month due to clipping but all panels face south and I expect clipping to be higher in the spring and fall.... BUT Xcel in NM doesn't carry over monthly excess at full retail so the energy lost in the spring and fall when HVAC consumption is lower is worth 75% less.

Kind of interesting... since SMA inverters only clip one MPP channel you have a basis for determining how much energy was ACTUALLY lost due to inverter saturation. So even with an oversize ratio of ~1.5 not all that much clipping... <3%.

Screen Shot 2019-08-27 at 8.50.19 PM.png

I live in Virginia. My net metering agreement is we get a credit for excess energy created which is good for 1 year. After looking at PVwatts it looks like the max my system will ever hit is 6.2kwh and for at most 4 hours a day. So maybe my concern is overblown.

[ButchDeal]

I live in Virginia. My net metering agreement is we get a credit for excess energy created which is good for 1 year. After looking at PVwatts it looks like the max my system will ever hit is 6.2kwh and for at most 4 hours a day. So maybe my concern is overblown.

6.2kW does seem a bit low considering your current production even with the different azimuths.

Can you post a graph of your daily output from SolarEdge monitoring on a decent day?

There are some settings for PVWatts for optimized system set up you should set https://www.solaredge.com/us/node/8195

[NullSlayer]

20190828_084302.jpg

[ButchDeal]

20190828_084302.jpg

ok from your reddit post you stated "We typically hit around 5-5.5 kw max production, but we did hit 6 a few times in July."

If this is more typical then you are not going to be clipping all that much.

[NullSlayer]

ok from your reddit post you stated "We typically hit around 5-5.5 kw max production, but we did hit 6 a few times in July."

If this is more typical then you are not going to be clipping all that much.

This makes me feel better. I appreciate your insight!