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mikemynis avatar image
mikemynis asked

Move from Growatt to Victron

I have 2 Growatt SPF 5000 ES (Solar Inverter+Charger combined) in parallel mode. This system can deliver up to 10 kW power out (230V) in single phase mode. I have 2 solar arrays. Each array connects to it's own Growatt. Both Growatts are connected to 5 parallel connected Pylontech US3000 batteries (48 volt).

Now I want to replace the Growatts with Victron equipment, because the Growatts have proven to be unstable and unreliable the last 12 months. I need something more stable, more reliable and more professional. So I want to switch to Victron.

But there are too many different types of Victron equipment. I don't know what to choose.

So, what do I need? Apparently I need an inverter that can deliver 10kW / 230V in single phase mode. (I have two groups behind this)

I also need to connect it to the battery bank, so it must charge the batteries during the day, only from solar. (never charge from grid). Grid must be used when solar is not available and battery SOC drops below 30%.

And I need to connect 2 different solar arrays. So I guess I need 2 MPPTs.

I was thinking of a Quattro or Multiplus 10,000VA or even 15,000VA plus 2 MPPTs. But which ones?
Or do I need two in parallel mode? I don't know what's the best combination. The Growatts are All in One. But I think Victron doesn't have AIO's.

Can someone help me out? What do I need and how do I connect them (schematic) and how to configure everything?

Thanks in advance,
Mike

victron products
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matt1309 avatar image matt1309 commented ·

Hi @MikeMynis


Massive question so I'll just answer the big parts.

Inverter: 1x10kva inverter, or multiple 5kva in parallel.

For ease of install I prefer just one unit so I'd go 10kva or 15kva but note these can't be paralleled with another 10kva for example whereas the 5kva models can be paralleled together (assuming same age/hardware revision).

I'd go multiplus unless you have multiple input power sources ie grid and generator. If you have gen and grid go quattro. If you just have grid input I would stick with multiplus (save your pennies a little).

Victron do offer an all in one Easysolar however given the size of your system I personally would go for mulitplus and separate charge controllers.


In terms of what MPPTs it depends how the PV panels are wired. ie how many in parallel (max amps) and how many are in series (max voltage). This will help determine what MPPT's are right for you. This might help:

MPPT Calculator - Victron Energy


In terms of a schematic I couldnt give one detailed enough but I prefer having central bus bars. With fused connections coming off the busbars, then a disconnect before each device.

So inverter, MPPT's and battery all connect to the centralised busbars via disconnects and fuses. VIctron does offer central bus bar type products however they are quite expense so I personally just use generic bus bars and fuse holders.


Hope this gives you a head start. Once you've narrowed down inverter/MPPT's I'd maybe watch a few install videos on youtube/victron professional website. Even if you're not installing yourself it's great for understanding the system and components.


In terms of configuring the devices I'd look into the manuals section and have a skim of multplus, MPPTs and any busbar/smart shunts you use. They have really detailed instructions. Only other point to mention is if you dont get a multiplus gx version you may need a seperate cerbo gx or similar device. I think of it as the brain/control panel of the system.


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frankmsc68 avatar image frankmsc68 commented ·
Hi Mike,i'm considering moving to victron equipment....Reducing a bit your actual needs to about 6kw...you could try the Multi RS Solar.It has 2mppt's with a good voltage range.If you're not interested in feeding back to the grid this might be an option,which i am thinking of going into....Everything else,i beleive, needs again more than one equipment....Best of luck,Frank
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7 Answers
Mike Dorsett avatar image
Mike Dorsett answered ·

Do note that you will also need a Cerbo or other GX device to interface the pylontech BMS data with the inverters and chargers for controll and protection. It also gives you useful system reporting functions that are essential in such a large system.

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ejrossouw avatar image
ejrossouw answered ·

Be aware the 8 & 10kVA units deliver 6.4 & 8kW which. Depending on where you are, not all models may by fully type tested and as such, approved for parallel connection to the grid by your DNO. As with your PV, I suspect you will have to look at a MPPT RS string inverter depending on your existing panel wiring configuration and the number of panels. The MPPT sizing tools now has a search function which should help a lot to identify the correct MPPT.

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Mike Dorsett avatar image
Mike Dorsett answered ·

I've not read a lot about Solar Assistant, but don't see it's need with the facility offered by the VRM portal. 2 second real time remote monitoring equals a LOT of data, 5 to 15 minutes is usually sufficient for remote monitoring. There is now also the Ekrano as an alternative to the Cerbo.

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mikemynis avatar image
mikemynis answered ·

Hi guys, update: I just ordered 2 x Victron Energy MultiPlus-II 48/5000/70-50 230V. I got a decent offer for them. It'll take 2 weeks for them to arrive.

Later today I will also order:
- 1 x Victron SmartSolar MPPT RS 450/200-TR (4 MPPT trackers)
- 1 x Victron Cerbo GX
- 1 x Victron GX Touch 70

Looking forward to changing everything and get the Victron system up and running. I will also get 6 x 550W panels and use 1 of the 2 Growatts for them and connect that one to an electrical water heater. And connect the house (coming from the Victrons) as backup "grid" input for this Growatt then.

That will also offload the house more. And when solar is insufficient for the water heater, then the Victrons can 'help'...

Thanks guys for your help and advice.

What do I need to configure / set everything up? How does that even work?

Kind regards,
Mike

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Fideri avatar image Fideri commented ·
@MikeMynis Looks good. I suspect that you will also need an MK3 interface to configure your multis and set them up for parallel operation.

Fideri

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mikemynis avatar image mikemynis Fideri commented ·

Good tip, Fideri. Thanks. Will add this to the list.

https://www.victronenergy.com/accessories/interface-mk3-usb

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Alex Pescaru avatar image
Alex Pescaru answered ·

Hi @MikeMynis

Congrats on your acquisition.

Now that "the dust has settled", please, can you enter a little bit in details and tell me what has been upsetting you about Growatts ?

Sorry for this question, here on a Victron site, but I am a person that likes to learn from other mistakes and knowing the downsides of Growatts maybe we can learn from them.

Thanks!

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mikemynis avatar image
mikemynis answered ·

Hi Alex,

Of course :-)

Well, the biggest problem I have with the Growatts is their charging logic, which in my opinion (and those of several others in the diysolar forum), is not logical at all.

It's Chinese logic, which is not compatible with my 'Western' logic.

When solar is up, I would expect the Growatts to send power to the house (the loads) at first. Then if there's power left, charge the batteries.

But that does not happen.

What actually happens is that as long as the SOC is below a certain percentage (I set it 30%), all solar goes to the batteries. No solar energy is going to the loads.

Instead, all power needed by the loads is coming from the grid.


So even if there is more than enough solar energy (let's say 4kW) this is all used for charging. What the house needs is taken from the grid.

I want it to first power the house and with what's left, charge the batteries.


Second issue are the relatively big power dips when it switches from battery to grid power at night, when batteries are dropping below 30% SOC.

These power dips makes all equipment (PC's, NAS, TV, etc) go down.


So I needed to install several separate (APC) UPS units everywhere. They say that Growatt switching is seamless, but in practice it's not seamless at all.

Now I hear the relays in the UPSes clicking like crazy when the Growatts switch to the grid. But at least the equipment behind the UPSes stay on.

Except the NAS UPS. That one still has an issue when the Growatts are dipping. It's not a smooth switch when going from battery power to grid. It switches several times, until it finally stays on the grid.


Then when you connect the Growatts in parallel, which is possible, you MUST use batteries. In other words: the Growatts need battery power to work in parallel.

I've had several times that when battery power dropped below SOC 30%, the batteries where shut-off, to "protect" them.

And when the Growatts shut off the batteries, they cannot work in parallel mode anymore. And then they disconnect the grid as well. No Passthrough.

So when that happened the house was completely powerless and dark.


This happened several times. Once when I was on holiday. So I came home to find a lot of defrosted food in the freezer and a lot of stuff in the fridge. All could be thrown away.


Another thing that annoys me with the Growatts is that when thet SOC drops below 30%, and they go to grid mode, they still keep powering themselves from the batteries. That's why I had to set the SOC lower threshold to 30%. Previously I had it set to 15%, but then, after reaching that level at night, they kept draining the batteries. At one point even to SOC 0%, which is very bad for the batteries.


Then they have this wifi-dongle, that's supposed to be easy to install, to get data. I tried it a zillion times. It never worked. That's when I switched to Solar Assistant, a 3rd party solution. That worked immediately.


Final point: rebooting both units goes wrong 9 out of 10 times. Then they simple don't work. They don't even go into grid mode. (pass-through mode).

To fix it you must make them completely powerless. Disconnecting grid, solar and batteries. Wait a few minutes. Then power up batteries and reboot the "master' Growatt.

When it's done and it starts delivering power to the loads, only then you can power up the second Growatt.

Sometimes it works when they boot together. But most of the times you need to follow this procedure.

All these things together gave me the feeling that I cannot trust the Growatts.
At some point I even started to call them battery-killers.


Of course you can use them very well in non-professional, non-critical situations. But they are not reliable enough to feed a home. When you use the Growatts, be prepared to always be around, just in case something goes wrong.


Mike


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Alex Pescaru avatar image Alex Pescaru commented ·

Thank you very much for the detailed answer.

I am finding known behaviors similar to another brand, MPP Solar.

I also seen there the fact that will provide solar only over a certain load, up until then only from grid... Odd.

Alex


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mikemynis avatar image
mikemynis answered ·

Final update:

I have ordered everything, including the RS 450/200-TR, Cerbo GX and the GX Touch 70.

Now I need to figure out how to connect everything, what wires/cables I need and how to configure/setup everything.

But I think I need to create a new topic for that.

Anyway, thank you all for your help and advice

Mike

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