Oversizing S3300 with 3.5kWp West facing panels.

[michaelwr]

Hello,
I am looking at pairing a S3300 with 8 x Jinko 440w JKM440N-54HL4R-B (Vmp 32.99, Imp13.34).

I had originally planned for 7 panels but the roofer can make my toilet stack flush with the roof so 8 are now possible. I would now be putting 3.52kWp through the S3300.

Does the inverter do any oversizing and am I worrying too much as I have a 35 degree pitch west facing roof, based in central Scotland so the chances of lab conditions is pretty low or does this look a good pairing?

p.s. I already have a 3.68kw system so have chosen the S3300 as it is G100 compliant should I be requested to throttle back output by the DNO. Has anyone used the FoxESS CT clamp with this system and is running the CT cable alongside the AC output cable for inverters sensible?

Thank

[Dave Foster]

It looks a good match, the voltage and max current of the panels are all within range and the inverter will clip the output should that one perfect day a year exceed it’s maximum output.

Is your 3.68kW system Foxess or another supplier ?

I’ve seen quite a few systems such as this using a CT clamp (or meter) with an export limit set to limit the output.

The only real issue with the CT clamp is the distance it runs, 10 metres is the standard but it can be extended up to 25 metres using CAT5 cable - if you are running for 25 metres next to the AC cable I would recommend using CAT5e cable because of the extra screening.

[michaelwr]

Hi, my 3.68 inverter is an SMA SB3800, it is no longer giving stats and the start up voltage is around 200V so with 8 panels I need something a bit quicker.

[Will]

You won't need an export limit set on an S3300 which a g98 as the default allowance is normally 3.68kW
Also worth noting that the S series doesn't come with or require a ct. Out of the box it will just push all the power up to the mppt limit down the AC connection which is really what you want.