question

anieuwstadt avatar image
anieuwstadt asked

ESS feeding into grid when AC PV and DC PV feed-in is disabled

SCENARIO:

  • Venus: V3.00~37 and V2.94 (did not try other versions)
  • System: 6x MPII 5k (v502), 3ph, Freedom Won, 2x RS450/200
  • ESS> Gridfeed-in> DC & AC turned OFF
  • ESS> Gridmetering> External EM540
  • ESS> Mode> Keepcharged
  • Input current limit: 36A

ISSUE: Grid feed-in occurs when excess feed-in is turned OFF. When the RS450s are disabled there is no feed-in (which makes sense). When the RS450s are enabled, grid feed-in occurs even though the Cerbo is set as below (does not make sense).

QUESTION: Are there conditions under which Excess PV grid feed-in should occur even when the Cerbo is set as below?


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ESS
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52913-1682690688695.png (135.3 KiB)
52905-1682690700988.png (113.4 KiB)
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3 Answers
nickdb avatar image
nickdb answered ·

Are all the inverters the same/same age, with similar serial numbers (4 digits after HQ)?

Have you verified all cabling is symmetrical?


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anieuwstadt avatar image
anieuwstadt answered ·

Hi @nickdb ,

Thanks for the help. The cable is symmetrical. The inverter pairs are not all the same version, but this is going to be resolved.

How would mismatched HW versions cause the ESS Feed-in when there this function is turned off?

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nickdb avatar image nickdb ♦♦ commented ·

There are differenct powerpacks if the gap is large enough.

I have personally experienced large amounts of constant feeding back with older and newer inverters paired in parallel.

Interestingly, making the newer one master yielded better results.

You should try keep each parallel pair as similar as possible, variations across phases are less important.

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anieuwstadt avatar image anieuwstadt nickdb ♦♦ commented ·
Dear Nickdb,


Will be sorting out the hardware revisions and will let you know if we experience the same.

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pete60 avatar image
pete60 answered ·

Have had the same issue with 6x MPII 5k (v502), 3ph system, it drains batterie to grid as soon as i connected the AcIn. Even if DC and AC PV feed in is disabled.

At last i "switched " master and slave units and vice versa......and now it works...yes crazy i know !

Dont ask me what causes this problem.


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