question

matthieujacobs13 avatar image
matthieujacobs13 asked

When is AC output 2 disconnected on Multiplus?

Hi,

The explanation of the AC output 2 is a little contradictory.

The datasheet of the multi II says that AC 2 is disconnected when AC in fails, while the manual says AC out 2 is disconnected in case of battery operation?

Which of these is correct?


Thank you

Multiplus-II
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Rob Duthie avatar image Rob Duthie commented ·

Depending on what model you have? The AC1 is the no break loads and AC2 is normal loads. So all critical loads are connected to AC1 in a power fail mode AC2 loads are all disconnected in a power fail mode.

Note: there are some mistakes in there manuals there were they have being transposed in the diagrams.

Regards

Rob D

NZ

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3 Answers
ejrossouw avatar image
ejrossouw answered ·

@MatthieuJacobs13 Both are correct. When mains fails AC2 "passthru" is disconnected and depending on your setup, the inverter will kick in and run off batteries. Typically AC2 is connected to non-critical loads In an off grid setup AC2 will also be disabled, but this function can however the changed, but it not recommended.

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matthieujacobs13 avatar image matthieujacobs13 commented ·

I understand this situation. However in the installation we are designing we will combine a solar inverter on the AC output and a mppt charge controller with solar power on the dc side. When the batteries are full, this power can be used to power the loads on the AC side, but I'm afraid the multi will then switch off the ac output 2 as it thinks the batteries are supplying power?

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ejrossouw avatar image
ejrossouw answered ·

Will the system run ESS in a grid parallel configuration? What is the purpose of the system? UPS or batteries used for self consumption? The deciding factor then typically is whether mains is available or not and not whether the batteries are in use. The ESS manual explains the modes e.g keep batteries charged etc. Self consumption systems typically off batteries in parallel to the grid and the inverter is on all the time. Power is always first diverted to loads, then batteries charging and finally feedin if required.

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matthieujacobs13 avatar image matthieujacobs13 commented ·

The system will function as a UPS. However in normal operation there will be surplus solar power and we want to use this to power loads on the ac out 2. There is solar power on the output (via a solar inverter) and on the DC side, with a charge controller. Other loads will run parallel to the Multi and do not have UPS functionality. Also no feed in is allowed.

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ejrossouw avatar image ejrossouw matthieujacobs13 commented ·

Do a search in the forum as the programming of the AC2 relay has been discussed. Apart from that, using ESS will do what you want by making use of all sources to limit grid consumption, store excess energy in the battery for use e.g when there is no PV or the grid fails etc. Hope it clarifies your concerns.

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matthieujacobs13 avatar image matthieujacobs13 matthieujacobs13 commented ·

Without feed in is it still possible to use surplus solar power to power the loads connected in parallel to the Multi?


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ejrossouw avatar image ejrossouw matthieujacobs13 commented ·

Yes, if you use it with an ET112 energy meter so the multi can have a view on total grid consumption and manage that aspect of the system. The multi is bidirectional and you can actually connect it via the ACIN only. AC1 is only really necessary if you require critical load functionality.

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safiery avatar image
safiery answered ·

@MatthieuJacobs13 Just write an assistant using relay and ACout 2. You can then configure to what ever you want.

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