Inverter Choice: SolarEdge, SMA SB3600TL or SMA SB4000TL?

[JH69]

This is for the OP, I fully understand your queries, however your chosen supplier should be specifying the inverter for you and explaining the reasons why.
There are many you could use, and also some can be set with different options to minimise the shading issues that you have.
So my advise would be to choose a supplier that understands how inverters really work, just one example would be how optitrack works on an SMA, and would you benefit from using this facility on your installation.

Without surveying your house it really is impossible to suggest which inverter would perform the best, although for different reasons many have their favourites.

I hope this helps.

Ps Most, not all but most DNO's require a maximum output of 16A, which is 3.68 KW without having prior permission to connect to the grid, some inverters are supplied this way(G83 approved), and some can be set to this.

Thanks Earthstore,

To be fair to the installer, I approached him to enquire about pricing for a SolarEdge system, and to ask how it would compare to SMA (as I’d had other quotes for SMA systems).

He’s had a look at the house, and listened to my thoughts and proposed an SMA system with 10 panels in one string, and 5 panels in another. The 5 panel string will cover the area that will get some shading to minimise the effect of it.

He’s said DNO approval won’t be a problem, but I asked him to quote for both the 4000 and 3600 so I could compare the difference in price.

I’m leaning towards the SMA system, but I’m undecided on which out of the two inverters to go for. This thread was about ensuring my thoughts were on the right track.

 

[Earthstore]

The only thing about putting 5 panels on one tracker is it may be doubtful if it would have enough voltage to kick a 4000TL inverter in IE 5x30V=150V, Of course it depends on the orientation of both arrays.
So it depends on the panel voltage really, and total system design.

 

[JH69]

The only thing about putting 5 panels on one tracker is it may be doubtful if it would have enough voltage to kick a 4000TL inverter in IE 5x30V=150V, Of course it depends on the orientation of both arrays.
So it depends on the panel voltage really, and total system design.

Both arrays would have the same orientation. Basically all south facing on the same roof.

 

[Somecamel]

I Thought SMA inverters couldn't handle uneven strings, I tend to use the Powerone 3.6 which is a lot more versatile

 

[SibertSolar]

Uneven strings are fine, so long as they are on different/independant MPP trackers.

 

[Somecamel]

Uneven strings are fine, so long as they are on different/independant MPP trackers.

I stand corrected then Is this just on the 4000TL I assume or does the 3600 do it as well?

 

[JH69]

Uneven strings are fine, so long as they are on different/independant MPP trackers.

Sunny Design seems to default to uneven strings (10 and 5). Anyone know why this is? What are the considerations when deciding how to spilt panels over 2 strings?

 

[SolarCity]

I can't be sure but I would say that this is due to the fact that one of the strings will be running at a higher voltage and will therefore start up earlier - although I would say that the actual benefit would be minimal.

Far better would be to consider the shading (however small) and adjust to suit.

 

[wstevew]

Yingli panda 265w are 31v

4000TL default startup voltage is 150w (can be dropped to 125)

Mppt input range 175 -500v per string.

Voltage out of tracker range?

 

[sedgy34]

Power one for me 2 individual strings on trackers
string of 10 no problem the 5 may be under voltage though would need to run through the design

 

[moggy1968]

Yingli panda 265w are 31v

4000TL default startup voltage is 150w (can be dropped to 125)

Mppt input range 175 -500v per string.

Voltage out of tracker range?

bear in mind output will drop with age, climatic conditions and installation losses.
You don't want to find that in 5 years time your voltage isn't enough to kick start the inverter 'cos you cut your calcs too fine. You need to give yourself a bit of margin

 

[JH69]

Yingli panda 265w are 31v

4000TL default startup voltage is 150w (can be dropped to 125)

Mppt input range 175 -500v per string.

Voltage out of tracker range?

I spoke to both my installer and SMA today about this. They both said pretty much the same thing: If Sunny Design accepts it, then the installation will be ok. While Sunny Design can't advise on what's the 'right' balance of panels on each string - that's location specific and up to the installer to figure out - it will flag it as an issue if there aren't enough panels on a string.

 

[cjapeterborough]

Based on your original post I would cast my vote for the 4000TL as you shouldnt imho design your system to limit your output to the max 3.6KW.

I purchased a 4KW system last June and the various software packages predicted an annual output of around 3000KWh/pa

I have a more or less East facing roof in Cambs and my total for the year was 3600KWh -on cool sunny days peak output hits 4KW

I am sure I have gained an extra 5% at least by not limiting the output to 3.6KW

Depending on the panel spec tolerances you could in theory end up with say a 4.20KW system (some panels are up to +5% output spec)
Dont know the yingli spec but again another reason not to cap the potential of your system.

If you are south of me in the uk I would expect a well designed south facing system to outperform mine by perhaps 10-20%
So the 3600 would hold you back certainly more than the £100 difference or 1-2% inverter efficieny differences
I have a 19 panel Schuco system split 10+9 on each mppt with no shading issues.
Sunny Explorer is all you need for monitoring and there is also additional software for android and such -the sunny beam again imho is
not really needed.

Hope this helps

 

[JH69]

Based on your original post I would cast my vote for the 4000TL as you shouldnt imho design your system to limit your output to the max 3.6KW.

I purchased a 4KW system last June and the various software packages predicted an annual output of around 3000KWh/pa

I have a more or less East facing roof in Cambs and my total for the year was 3600KWh -on cool sunny days peak output hits 4KW

I am sure I have gained an extra 5% at least by not limiting the output to 3.6KW

Depending on the panel spec tolerances you could in theory end up with say a 4.20KW system (some panels are up to +5% output spec)
Dont know the yingli spec but again another reason not to cap the potential of your system.

If you are south of me in the uk I would expect a well designed south facing system to outperform mine by perhaps 10-20%
So the 3600 would hold you back certainly more than the £100 difference or 1-2% inverter efficieny differences
I have a 19 panel Schuco system split 10+9 on each mppt with no shading issues.
Sunny Explorer is all you need for monitoring and there is also additional software for android and such -the sunny beam again imho is
not really needed.

Hope this helps

Thanks!... that's really useful info and it has just confirmed my thougths on the subject: I'm going for the SMA SB4000TL.

I know it will be a rare occasion, but it will be nice watching it peak at around 4Kw.

Interestingly I spoke to SMA today (to ask about # of panels per string), and also asked them about 4000 vs 3600. They said that apart from the capped output they are otherwise the same. So there should be no efficiency differences at lower outputs. The only reasons to not go for a 4000 is the extra cost and the need for DNO approval.

 

[cjapeterborough]

I think they are shipping the 4000TL-21 now which may be slightly improved.
Make sure you get it installed with the latest 3.20 firmware as there are a few annoying
reporting bugs in sunny explorer (inverter doesnt know that sometimes there are more or less than 30 days in a month

 

[Durky]

Solar Edge has the added benefit of a 12 year warranty over SMA at only 5 years. My customers really like the added peace of mind.

 

[Mr.Shing-A-Ling]

The SolarEdge has a 12 year warranty which is another consideration. I have just had a SolarEdge SE4000 fitted with 12 x SunPower E20 333

 

[danesol]

If you go SMA, save your money and don't go for the sunnybeam. Laptop does all and more for free (bar the cost of a wireless dongle if you don't have wifi built in to the laptop).

^^^^ agreed

 

[Eco Deal]

Solar edge as online monitoring which can also pin point under performing panels.

 

[Mr.Shing-A-Ling]

Solar edge as online monitoring which can also pin point under performing panels.

The SolarEdge Monitoring Portal is a nice feature.