rvicev avatar image
rvicev asked

MultiPlus-II and APsystems DS3-L

I recently contacted APsystems EMEA with a technical question relating to dimensioning of DS3-L microinverters and Victron´s MultiPlus-II (Victron´s Factor 1.0 Rule).

Instead of an answer to my question, they responded : ¨our micro-inverters can not be used with microgrid or off-grid installations. If you do so : warranty void¨.

This is most unusual as APsystems have a white-paper on their site detailing how their YC500´s can be used in a Victron microgrid and in off-grid installations. I believe to have read elsewhere that since then all their micro-inverters support frequency shift power management for AC-coupled batteries.

I pointed this out to them, but got no further response. Don´t know why, i.e. whether they have changed their policy, whether there have been technical problems, or whether I simply got to the wrong support person (??).

Anybody using Multiplus(-II) in combination APsystems DS3-L micro´s ?

AC PV Coupling
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2 Answers
rvicev avatar image
rvicev answered ·

Well, in the mean time I have found the answer : they have changed policy for reasons unknown.

Back in 2018 APsystems published a white paper on the certification of Victron Multiplus and their YC500 micro-inverters in microgrid & off-grid environments :

but this no longer appears in the visible part of their website(s) now.

Don´t know why, but any current info on APsystems website(s) says : off-grid and micro-grid are not supported and any ¨AC-coupled¨ PV should not require frequency shift power management ......

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klim8skeptic avatar image klim8skeptic ♦ commented ·

You might be better of looking at Enphase.

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rvicev avatar image rvicev klim8skeptic ♦ commented ·

I did look at Enphase (7-series,as the 8-series are not available here yet), and got confused every time.

Enphase appears to me as a very much ´closed´ system, unable to communicate with Victron Multiplus, and :

- it´s not clear to me whether Enphase supports frequency shift power management (needed to lower output in case batteries are almost full),

- all examples given by Enphase suppose a grid connexion,

- it´s not clear to me which components components of the Enphase biosphere I would need as a minimum :

a) IQ7(-X, -A, -+),

b) Envoy (probable needed for config and updates?)

c) Q-relay (apparently this shuts-down the IQ7s (via CPL communication) in case of grid failure - I suppose if you are off-grid this may no longer be needed ?)

d) other ?

Dimensioning (in view of Victron´s 1.0 Rule) is also unclear. For example, for the Enphase 7+ they state :

- recommended modules : 235 - 440 Wp

- output (AC) : max 295 VA

I can not possibly imagine that a 235 Wp panel gives an AC output of 295 VA, nor a 440 Wp panel giving only 295 VA. So how do I apply Victron´s 1.0 Rule if I intend using 390 Wp panels ?

Enphase marketing really excels in HBSC ........

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jfbo37 avatar image
jfbo37 answered ·

Je suis tombé sur ce site espagnol, ils parlent de compatibilité avec le Multiplus en AC-Coupling avec Frequency Shift

Microinversor Apsystems DS3 de 880 W para instalaciones residenciales –

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rvicev avatar image rvicev commented ·
@jfbo37 Oui, ça doit fonctionner (car APSystems prétend de repondre aux exigences de VDE-AR-N 4105). Seul bemoil : ils refusent de donner de support pour une solution ¨AC-coupling / off-grid¨, donc en cas de soucis pas de support / garantie ......

Enphase doit fonctionner aussi, mais ne sont pas très enthousiast non plus à propos d´un tel solution.

Hoymiles dite de supporter AC-coupling / off-grid sans problèmes.

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honu avatar image honu rvicev commented ·

VDE-AR-N 4105 is not good enough for Frequency shifting, VDE-AR-N 4105 is only a ON/OFF system. For AC coupling you need a progressive shifting.

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honu avatar image honu commented ·
Information found on this Spanish website : 

Operating modes
Grid connection: This microinverter works connected to the grid, synchronizing with it. It can be placed in existing inverter installations. In the event of a power outage, the equipment will be disconnected.
Isolated: This microinverter does not work in offgridd mode.
AC-Coupling: This inverter can work in AC-Coupling with Victron Multiplus inverters. It is installed in the AC-Out of the inverter. When the battery is full, the Multuplus increases the frequency and stops the microinverter from producing. In a few months it will be available with an update that includes a specific network code for this operation, so that it is capable of Frequency Shifting. With this operation, the microinverter will regulate to produce only the power demanded by the load instead of cutting off.

Well ... do not know if this update had ever gone live.
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