The GoodWE 3648-EM supports 27.8% PV oversizing (confirmed by GoodWe support)

[cpbotha]

I am posting this information here, because I could not find anything online before.

I just received confirmation from [email protected] that the GoodWE 3648-EM 3.6kW inverter, rated for 4600W max PV input, does support PV oversizing by ~27.8%.

(In the brochure for the ES units, GoodWE explicitly advertises 30% PV oversizing. However, this is not mentioned in any of the EM-series documentation, which is why I sent them this request for information.)

This is the email reply I received from [email protected], within one business day:

Quote

Hi,Charl
This is jesse.I will give you the info.
As for GoodWe 3648-EM, it supports ~27.8% PV oversizing.
Hope that could help you.

Dear Customer, Goodwe HQ will close for Spring Festival from 2nd-11th Feb.2019, back to work at 12th Feb., please be noted. Thank you.
（Goodwe customer satisfaction survey 2019: https://www.wenjuan.com/s/qmuYryZ/, welcome to participate. Thank you.）

Best Regards

Should you have any questions, please do not hesitate to contact me.
Jesse Lee 
Overseas L2 Technical Support Engineer
GOODWE POWER SUPPLY TECHNOLOGY CO.,LTD.
—————————————————————
M  +86 13057431082    T  +86 512 67375149
A  189 Kun Lun Shan Rd, Suzhou, Jiangsu, China

 

[___]

That may be true, but watch out for the current limitations. I don't know about this one specifically, but on some of their models they have something like an 11A maximum current on the MPPT. That means that to get the full power out of the unit you have to push the voltage up, and to do that you need long strings all pointing in the same direction, which means you need plenty of north-facing roof space.

Then again, it does have two MPPTs which also helps a bit.

[cpbotha]

26 minutes ago, plonkster said:

That may be true, but watch out for the current limitations. I don't know about this one specifically, but on some of their models they have something like an 11A maximum current on the MPPT. That means that to get the full power out of the unit you have to push the voltage up, and to do that you need long strings all pointing in the same direction, which means you need plenty of north-facing roof space.

Then again, it does have two MPPTs which also helps a bit.

Indeed, the specs of the ES and the EM even state that you can only have one string per MPPT. On the other hand, you get two MPPTs, each of which can go up to 550V.

[cpbotha]

I continued the conversation with GoodWe, and now have more clarity.

The 27.8% oversizing they claim, is on the nominal PV input of 3600W, bringing the maximum to 4600W. In other words, the maximum PV input they state in the specs, already has the oversizing calculated in. The 3600W nominal PV input is not mentioned in the manual anywhere, but can be derived from the 36 in the model number 3648.