What is your questions excatly?
For the AC Coupled PV inverter -
- If the power of the AC inverter is less than the power of the multiplus, it may be connected to AC out1.
- If the Power of the PV inverter is greater than the multiplus, it has to be connected to AC in. However, this will not work in the absence of a grid connection, and other equipment will be needed. See tutorials on ESS systems.
- You cannot operate the multiplus without a battery. This will lead to damage.
- AC out2 is normally only powered when AC in is connected, however this can be changed by programming.
I had some explanatory description but it has not been posted for some reason.
Now I do post three different layouts from which i cannot figure out which is the best.!!!
I am using dummy load to accept surge current in case the main load is cut off abruptly
and the battery is full !!
Layouts A and B will NOT work, as there is no grid connection. so the PV inverter will not operate.
The inverter power needs to be greater than or equal to the PV inverter power, so you’ll need 5000W as minimum.
The ‘dummy load’ is not the way to deal with surges, a proper surge arrestor should be permanently wired to the output of the PV inverter.
Ok. layout_c
I used the wrong term referring to the “surge current” .
I agree that the surge arrestor has to be placed directly and not through any switch
I am referring to the situation when the load for some reason is cut off abruptly and
pv continues to provide power.
When this happens
Victron plus II sees that there is power excess (since its battery is fully charged ) and increases frequency.
Fv sees the increase of frequency and it reduces power until it shuts down. T
his short time o fexcess power can damage the equipment.
What solution do you suggest ?
If your system is configured correctly on the Multiplus 2 GX or a separate GX (cerbo), and the PV inverter supports freq shift or direct comms to the GX, there is no problem and no extra safety equipment is needed
Is there any other reason than the information that can be given by the Multiplus 2 GX model ?
You need a GX to have freq or direct control of your pv inverter, so either a cerbo/ekrano or an multiplus 2 GX
-
The only reason I see you suggest the GX model
is that there is an integrated information center in it.
-
i,e.
”The core difference is that the Victron MultiPlus-II GX has an integrated communication center (a “GX device”), while the standard MultiPlus-II does not.It seems to me that if i do not wand to spend more money than it is needed
Victron Multiplus II can be used !
Is that wright ?
( from a first look multiplus 2 gx here is much more expensive than multiplus 2.
If the difference in price is small obviously the gx will be preferred .)
No thats not right, you need an GX to use a battery with bms or when you use a separate shunt,
some assistants like ESS can not run without a GX,
A lot of specific settings are only available from the GX,
and there are a lot of other scenarios where you need a GX…
I do agree with you for all the information that GX model can supply
since i have been doing this job for 35 years with many apps in
industrial automation scada ( citect )and industrial communications.
The layout we are discussing will be installed in existing remote stations
and will be only for heating the premises, and nothing else.
The SMA Sunny Boys 3300 are existing (as leftovers)
Is there a point of using a GX?
( or just a simple Multiplus II )
you can always use a ras pi or beaglebone to run Venus instead of an official GX device. You may need some additional interfaces e.g. Mk3/USB to communicate with the inverter.
If you are using lithium batteries, the you really need this and the BMS to run the system correctly.