Solaredge HD Wave adding a second inverter

[Rmusclow]

Hello,
We have a grid tied 13.8 Kw system with an SE10000H inverter which states it's maximum output is 10,000 watts. We had a company design the system and I installed. I just realized that the inverter will not realize the maximum potential of the solar array (not sure what the designer was thinking). We have 3 strings on the array each with 4,620 watts. I'm going to install a 5,000 watt second inverter and move one string to the second inverter. My question is can I connect the AC lines from the two inverters together prior to going into the DC disconnect. I would connect them with an insulated terminal block. I tried contacting Solaredge Tech support and that is beyond worthless.
Thanks for any advise!

 

[BentleyJ]

If 13.8kW is the STC rating of the system its doubtful it will consistently produce more than 10kW except for under rare, ideal conditions. Have you verified the system is in fact "clipping"? Its easy to see on a daily production chart. The curve will increase as the sun comes up and instead of the typical smooth, rounded top peak, it will cut off and go horizontal until afternoon then will start to fall off.

 

[Rmusclow]

If 13.8kW is the STC rating of the system its doubtful it will consistently produce more than 10kW except for under rare, ideal conditions. Have you verified the system is in fact "clipping"? Its easy to see on a daily production chart. The curve will increase as the sun comes up and instead of the typical smooth, rounded top peak, it will cut off and go horizontal until afternoon then will start to fall off.

I haven’t been able to use the Solar edge monitoring app. The inverter is in a building 400 feet from our house and even with a repeater I can’t get a signal. SolarEdge tech support was no help. The few times I have looked mid day it is maxed out at just under 10,000 watts. We are in the 4 corners region and near ideal location for Solar.

 

[BentleyJ]

At that elevation and average temps., you do have great conditions for solar. It still makes sense to verify how much clipping is actually happening. When you say the inverter is maxed out at 10kW mid-day, how long does this condition last, 30 min around noon? Not much being lost in that case. If you are maxing out at 10:30 am and this persists till 1:30 pm then maybe its worth adding the 2nd inverter.

Regarding your question about combining AC. Ultimately the AC would get combined at the panel with each inverter having its own back-feed breaker in a conventional 2 inverter set up. Alternately there could be a combiner box where each of the 2 inverters has its own breaker then feeds into the panel. Theoretically, combining them upstream would essentially be the same as far as the inverters are concerned but the protection provided by properly sized, separate breakers for each inverter is lost.

 

[Rmusclow]

At that elevation and average temps., you do have great conditions for solar. It still makes sense to verify how much clipping is actually happening. When you say the inverter is maxed out at 10kW mid-day, how long does this condition last, 30 min around noon? Not much being lost in that case. If you are maxing out at 10:30 am and this persists till 1:30 pm then maybe its worth adding the 2nd inverter.

Regarding your question about combining AC. Ultimately the AC would get combined at the panel with each inverter having its own back-feed breaker in a conventional 2 inverter set up. Alternately there could be a combiner box where each of the 2 inverters has its own breaker then feeds into the panel. Theoretically, combining them upstream would essentially be the same as far as the inverters are concerned but the protection provided by properly sized, separate breakers for each inverter is lost.

Thank you Bentley for the input. I’m still working on trying to get the monitoring up and running. I’ll take your advice and hold off on a second inverter until I can adequately monitor what they are producing.

 

[zanydroid]

I haven’t been able to use the Solar edge monitoring app. The inverter is in a building 400 feet from our house and even with a repeater I can’t get a signal. SolarEdge tech support was no help. The few times I have looked mid day it is maxed out at just under 10,000 watts. We are in the 4 corners region and near ideal location for Solar.

I hate to say it but you might consider Powerline networking. Usually it's a pile of turd to install such a system for regular use cases, but I bet you can reliably get telemetry through it. And probably simpler to make work than EG directional WiFi or pulling some cat6 or fiber.

 

[zanydroid]

Not sure what was meant by the breaker discussion but by default you need to put each inverter on its own branch circuit, unless the manufacturer says otherwise (EG for microinverters). And feeder/subpanel config to be determined by load calculations.

 

[400bird]

You should use a breaker box so you can have circuit protection on each inverter individually.

However, as has been mentioned, you probably aren't missing much production.
Over paneling is pretty standard practice as panel output normally maxes out at about 80% of nameplate. So, for those rare days where we get more output it probably isn't worth the expense.

 

[zanydroid]

The telemetry is a good investment. Maybe someone knows how much SolarEdge saves locally when it can’t find the network (otherwise will have to wait 9 months for data, ?)

 

[400bird]

Very little. I had my Solar Edge hardwired network connection unplugged for 3 months. I didn't notice any of the missing data update when I reconnected. I never went looking deep for it, so I might have missed the small amount of locally stored data that it uploaded

 

[BackyardBandit]

SolarEdge has a 5G cell card that is pretty much plug and play for communication instead of Wi-Fi. Pretty simple to install and configure in SetApp.

 

[Hedges]

Hello,
We have a grid tied 13.8 Kw system with an SE10000H inverter which states it's maximum output is 10,000 watts. We had a company design the system and I installed. I just realized that the inverter will not realize the maximum potential of the solar array (not sure what the designer was thinking). We have 3 strings on the array each with 4,620 watts.

Are all panels oriented the same, or are some on different roof faces?
If different, what orientations and slopes? How about a photo, from google satellite etc?

As was mentioned, actual power output (PTC or NOCT) is generally less than under standard test conditions (STC) meaning flashed with one full sun in a lab while at 25 degrees C. Even oriented the same, 10kW is about the right size inverter to fully utilize the panels. We call that "overpaneling" and do it on purpose.

If you want to add an inverter, consider one that offers backup when grid is down. Some are batteries optional, so you can have limited daytime power without a battery. Just get separate panels for such an inverter; the mounted panels have Solar Edge optimizers. You can get a StorEdge inverter that takes a battery but I think those batteries are more expensive.

 

[Rmusclow]

Are all panels oriented the same, or are some on different roof faces?
If different, what orientations and slopes? How about a photo, from google satellite etc?

As was mentioned, actual power output (PTC or NOCT) is generally less than under standard test conditions (STC) meaning flashed with one full sun in a lab while at 25 degrees C. Even oriented the same, 10kW is about the right size inverter to fully utilize the panels. We call that "overpaneling" and do it on purpose.

If you want to add an inverter, consider one that offers backup when grid is down. Some are batteries optional, so you can have limited daytime power without a battery. Just get separate panels for such an inverter; the mounted panels have Solar Edge optimizers. You can get a StorEdge inverter that takes a battery but I think those batteries are more expensive.

Thank you, all panels are on a south facing roof with a 4/12 pitch.

 

[Rmusclow]

I hate to say it but you might consider Powerline networking. Usually it's a pile of turd to install such a system for regular use cases, but I bet you can reliably get telemetry through it. And probably simpler to make work than EG directional WiFi or pulling some cat6 or fiber.

I don’t think it will work because the power line goes from our service panel to a sub panel in a barn then to a sub panel in the shop where the panels are installed. From the little research I did it looked like it would not be a viable alternative.

 

[Rmusclow]

SolarEdge has a 5G cell card that is pretty much plug and play for communication instead of Wi-Fi. Pretty simple to install and configure in SetApp.

After buying the antenna, gateway, and repeater, I’m reluctant to spend 400 plus dollars on the cellular card which only will cover access for 5 years. I think I will run a hard wire first. I’ve ordered a new router to see if that may help, ours is needing updating anyways. It is frustrating when solar edge advertises that their repeater extends the wi fi signal 1,200 feet which it clearly doesn’t. Solar edge support is of no use, there only suggestion was to hire a certified installer.

 

[zanydroid]

I don’t think it will work because the power line goes from our service panel to a sub panel in a barn then to a sub panel in the shop where the panels are installed. From the little research I did it looked like it would not be a viable alternative.

The 400ft is pretty rough to deal with.

The consumer grade power line and cable equipment is pretty cheap to try. You lose a few dB potentially across the breakers. Not sure how that compares to the dB you lose from going 400 ft.

Is there TV cable going there? That would allow MoCA (assuming any splitters on the path are accessible be upgraded to broadband frequency, a lot of old ones cut frequency that MoCA uses).

I believe directional WiFi antennas can make the distance if it’s unobstructed.

i believe for wired connection going 400 ft people would strongly recommend using fiber to avoid ground loop and issues.