SolarEdge question

[ggunn]

I have a design on my plate using a SolarEdge inverter and bifacial modules, specifically the Sirius ELNSM54M-HC-410. Maximum string lengths (STRMAX) for a given optimizer is a maximum connected DC power divided by a single module power. The module data sheet shows FRONT STC as 410Wp and BACK STC as 287Wp. Incidentally, this system will be a low slope flush mounted array, so I do not anticipate much contribution from the back side of the modules.

Here's the question: for STRMAX calculation purposes are these 410W modules, 697W modules, or something in between?

 

[jaggedben]

That's a good one. I think if you want to be sure the Solaredge warranty isn't affected they are 697W modules. Unless they tell you otherwise.

 

[ggunn]

That's a good one. I think if you want to be sure the Solaredge warranty isn't affected they are 697W modules. Unless they tell you otherwise.

I haven't run the numbers yet but I am concerned that doing that may drive STRMAX below the minimum string length.

 

[Zee]

All I know is to expect 5-30% extra for bifacial, per Google AI.
The rated 287W seems very high at 287W/410W = 70% .

My guess , either find Code (doubt it addresses this) or find the absolute maximum gain if it were on a white roof tilted way the hell up.

Maybe use micro-inverters instead? Then it limits the issue to clipping at worst.
Not to mention avoiding solaredge.

Or maybe another RSD solution. I used SMA inverters plus APsmart or something on a big bifacial job tilt racked over white metal roofs.

What pitch are they at?

 

[ggunn]

All I know is to expect 5-30% extra for bifacial, per Google AI.
The rated 287W seems very high at 287W/410W = 70% .

My guess , either find Code (doubt it addresses this) or find the absolute maximum gain if it were on a white roof tilted way the hell up.

Maybe use micro-inverters instead? Then it limits the issue to clipping at worst.
Not to mention avoiding solaredge.

Or maybe another RSD solution. I used SMA inverters plus APsmart or something on a big bifacial job tilt racked over white metal roofs.

What pitch are they at?

The array will be flush mounted on a roof with 5-10 degree pitch. Modules and inverter are set - not my decision. I agree that the backside Wp seems very high. There is nothing that I can find in 690 which references bifacial modules.

 

[jaggedben]

Maybe try to get the module manufacturer to stipulate an appropriate STC to use given the mounting specs?

 

[solarken]

I have a design on my plate using a SolarEdge inverter and bifacial modules, specifically the Sirius ELNSM54M-HC-410. Maximum string lengths (STRMAX) for a given optimizer is a maximum connected DC power divided by a single module power. The module data sheet shows FRONT STC as 410Wp and BACK STC as 287Wp. Incidentally, this system will be a low slope flush mounted array, so I do not anticipate much contribution from the back side of the modules.

Here's the question: for STRMAX calculation purposes are these 410W modules, 697W modules, or something in between?

Use the Solaredge designer tool and if that module is not in the library pick list, add it manually using the data sheet info. If this is flush mounted on roof I would not worry about any bifacial increase from the back side. I would use 410W.

 

[ggunn]

Use the Solaredge designer tool and if that module is not in the library pick list, add it manually using the data sheet info. If this is flush mounted on roof I would not worry about any bifacial increase from the back side. I would use 410W.

It's not that I am concerned that the back side would contribute much if any additional current to Isc given the nature of the array design, it's that I want to make sure that I don't put the SolarEdge inverter and optimizer warranties in jeopardy. Your point is well taken, however; if the SE design tool passes a design it would be something that could be used to defend it should the necessity arise.