Why a SB 3000TL-20 for a 4kW array?

[clivep]

My installation has just been completed.

I have 16 x Hyundai HIS-250MG panels connected in 2 x 8 strings to a Sunny Boy SB 3000TL-20.

This inverter and configuration is as recommended by Sunny Design.

However...

The evaluation of design sheet gives PV peak power of 4.00 kWp, max. DC power of 3.20 kW and max. AC power of 3.00 kW with a nominal power ratio of 80%.

This appears to me to be saying that no more than 3 kW AC can ever be generated. My installer assures me this is not the case. What am I missing?

 

[pvman]

Although the Sunny Design software shows the configeration will work, this is not the same as it being the correct inverter for your system. There will be times when the the inverter will be overloaded, by the DC power, and shut down. The max input for a SB3000TL is 3.2kW
A more suitable inverter may be the SB4000 but this would depend on your DNO, another alternative would be Aurorra 3.6 (these last points may not be valid because of the inverter situation).

Tom

 

[SolarCity]

I would say that a 3000TL is a bit undersized for a 4kWp system

 

[Somecamel]

The SMA 3800 is a much more suitable inverter

 

[northernsun]

Although I'd say your inverter is a touch undersized you will still have a decent system. Yes, you are tight that the system will never have an AC output of greater than 3kw- but it will be working a lot better when the DC input is lower than a bigger inverter would. So , although you will lose a bit off the top end, you will gain from having a better performing inverter in less than perfect conditions- which is a lot more common than perfect conditions, over the year your system will be running at 2-3kwp a lot more than 3-4kwp. Hope that makes sense!

 

[sharpener]

Not sure about that, I know it's conventional wisdom but the efficiency curves are almost identical right down to 200W, and the 4000 actually has a lower minimum MPP voltage.

Hopefully armed with these responses you will get him to agree to change it for something more suitable and deal with the resulting MCS/FIT paperwork issues. What did the contract say? My installers changed the spec at the last minute from SMA 4000TL to StecaGrid 4kW, but at least it is rated for the full output.

 

[clivep]

I originally anticipated the SB4000 would be the inverter for the system but this was not recommended by Sunny Design. Sunny design definitely gives the 3000 as the recommended one.

In fact Sunny design did not show the 4000 as a highlighted option but if you manually put it in then it says it is compatible with a marginally better annual output (a handful of kWh from memory).

I think all the other Sunny Boy ones between the 3000 and 4000 were reported as not compatible.

 

[powervan]

sunny boy 3300 or 3800 the way to go!! though HF range good!!TL4000 not for me on this occasion but im lazy and dont like EARTHING THE ARRRRRRRRRAY

 

[Maff]

After Thursday I dont think you will need to earth the array anymore:hurray:

 

[powervan]

YEH BABY!!! is this the new WOTEVA it is?? be good to stop that debate on hear!!!!!! how i like it ONE RULE SIMPLES for a simple person!!