Do I need the GX feature?

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1-victron-user asked Jul 6, '23

Do I need the GX feature?

Hi everyone.

I am considering a home battery storage system and gathering as much information as I can in order to have everything ready for the eclectrician.

I am thinking to go with the Victron Multiplus II 48/5000 and 15KW EVE battery racks. I can see that there are 2 inverters, one with and one without the GX feature. As I don't know what this actually does, I am wondering if the non GX will do everything for a setup without solar PV. I might have one in the future though.

Another question... Can the CT clamp be connected near the inverter or has to be at the house board? The inverter will be located in the garage, about 10 metres away from the consumer unit.

Thanks in advance for your help.

ct

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matt1309 commented · Jul 06, 2023 at 12:57 PM

I would go with GX device as it allows for far more functionality, especially if you're grid connected. You can use a raspberry pi (cheaper DIY option) or external gx device but built is in about the same cost I think.

In terms of CT clamp it goes on income grid connection wherever that is.

Personally when you run grid power from house to garage i would run a couple of cat 6 ethernet cables one for internet connection and CT clamps.

If you have no loads on grid incoming supply you can put CT in garage ie.

if you wire it:

1. Grid -> garage -> inverter -> house loads. then you can just use CT in garage as there's no loads between grid and garage.

But if you've got

2. Grid -> House loads

2. Grid <-> garage <-> inverter then you'll need CT as soon as grid comes in before House loads and before inverter.

Essentially if you're wiring loads and inverter all in parallel with house loads on ACIN of multiplus then yes you do need CT at income grid (likely at house).

If grid goes straight to the garage and then house is powered on ACOUT of multiplus then CT can just be down in the garage.

Not option 2 means house loads wont stay on when grid goes down as you would back feed into the grid. Whereas option 1 all loads are on output of inverter so would stay on if grid goes down (and earth arrangements are setup correctly for islanding)

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1-victron-user matt1309 commented · Jul 06, 2023 at 01:45 PM

I am not sure if the electrician will be using the last available fuse space from the house consumer unit or if he is going to tap before the consumer unit... Sorry I am not an electrician.

In my mind I think:

1) 32A fuse from the consumer unit > Garage > inverter ACIN.

Then AC Out 1 to several sockets just for the garage.

2) As 1 but first connection before the house consumer unit, with the 32A RCD fuse before reaching the inverter.

In both cases connecting the CT Clamp in the garage.

If possible I would want to have only 1 armoured cable to the garage as it's detached from the house and it will need to run underground for a few metres.

Also, can't the multiplus II communicate through WIFI?

I can't see a way for my router to have a cable connection from the house to the garage.

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matt1309 1-victron-user commented · Jul 06, 2023 at 03:20 PM

I would run cat6 when you run the power wire down to the garage.

I would also run 4 cores to garage, so you can have ACOUT power running to the house also. So you have offgrid sockets in the house (nice to have feature).

You'll need CT before any loads house or inverter.

You can maybe using ET112 and send that over internet/lan but CT is less laggy if you can get away with running another cat 6 down to garage for that.

Personally If it's only 10m and the inverter is 5kva+ i would ask electrician to run 4 core armored cable to garage with cat 6 for internet, 2 cores for grid power to multiplus and then the other 2 cores to run ACOUT of inverter back to the house.

So house power essentially runs via the garage ie

grid -> (via 2 cores) garage ->ACIN inverter ACOUT - > (via other 2 cores) house

That way house will stay with power on in grid outages. And the cost difference between 2 and 4core wire over 10m is minimal compared to price of overall system. You'll also need a few extra disconnects but again minimal cost in grand scheme of the system (and if nothing else it's pretty cool having power on when no one else does)

Not sure rewifi question. I'd highly recommend running the cat 6 ethernet at the same time, it's just more reliable even if wifi is supported.

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Answer 1 · 2023-07-06T13:09:30Z

nickdb answered · Jul 06, 2023 at 01:09 PM

Get a standard inverter without a built-in GX and rather add a cerbo separately. The cost is about the same but you get more connectivity and performance, so it is better in the long-run especially if you intend adding things later.

The GX is required for managing multiple charge controllers and smart (managed) batteries.

It also provides a ton of monitoring and remote control and is the heart of the Victron Ecosystem.

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1-victron-user commented · Jul 06, 2023 at 01:52 PM

If GX is required for managing the batteries, then there is no point tho get the inverter without it, or am I missing something?

This is the system I am thinking of purchasing:

https://www.fogstar.co.uk/collections/server-rack-batteries/products/fogstar-energy-48v-15kwh-rack-battery-bundle

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nickdb ♦♦ 1-victron-user commented · Jul 06, 2023 at 02:36 PM

It comes in two flavours, built in or external. External is better.

Get normal inverters, and buy a separate Cerbo GX.

That is also an uncertified battery.

Certified and supported ones can be found here:

https://www.victronenergy.com/live/battery_compatibility:start

You don't have to use a supported battery, you just must appreciate that it may or may not work as expected, and that can change as software changes. You and the battery manufacturer have to sort out any issues.

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kevgermany ♦♦ 1-victron-user commented · Jul 07, 2023 at 03:03 AM

If the compatibility is good, the batteries/BMS manage the multiplus charging through the GX device. Not the multiplus managing the batteries.
But there are plenty of posts here with incompatibility issues, despite battery makers' claims.

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