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thanar avatar image
thanar asked

MultiPlus 12/800 doesn't connect AC-in

Having issues with a new Multiplus 12/800 here, that I got to use as a UPS unit on a solar plant… inverting from DC works fine, however connecting to AC-in fails.

356193770-10163099046241110-6276306342242535870-n.jpg

As you can see in the screenshot, AC-in is healthy, however as soon as the internal switch closes, it opens immediately and pops an “under voltage” error on the NS protection log, accessible through VE.configure.

Charger-only mode doesn’t work either, internal relay again trips every now and then and the unit doesn't charge.

Any ideas?

ups
356193770-10163099046241110-6276306342242535870-n.jpg (67.3 KiB)
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mvas avatar image mvas commented ·

I do not see any screenshot?
Could it be a Neutral-to-Ground issue?

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2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Maybe a bad/loose connection somewhere in the AC input that cause a voltage drop as soon as there is a load.

Check that the GST18 connector sits firmly.

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thanar avatar image thanar commented ·

I'll make sure I double-check that one, I'll replace the whole cable to be sure. However, this happens even with no load connected. What would be the AC-in current when switching with no load?

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thanar avatar image thanar thanar commented ·
All cables redone. Same issue persists.
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JohnC avatar image
JohnC answered ·

Hi @thanar

The main clue is the 'under voltage' notification. You've discounted that, but best not to do so until you've checked it thoroughly.

No load you say, but do you have the batt charger enabled?

Try limiting the AC Input and Charge Amps. Also, enable Dynamic Current Limiter, so it will bring on the ACIn slowly, not in one hit. With a little luck, you may actually be able to spot a dip in the AC voltage as this happens.

You could also try unticking the Ground Relay to see if that makes a difference. Already mentioned, but might be that too.

Even Live/Neutral swapped?

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thanar avatar image thanar commented ·
What do you mean “I’ve discounted the «low voltage» notification”? I definitely have not. The AC-in is connected to a tested AC supply, able to provide at least 16A at 230V.

Anyway, just to be sure, I tried all of your suggestions, even reversed L/N, with no change whatsoever.

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