question

Juraj Nikolov avatar image
Juraj Nikolov asked

comparing mppt multiplus II GX vs easySolar II

I have a question which ones of solution is better and if it is necessary to solve it or nor.
1) multiplus II GX 5kva
3x mppt 150/35 bluetooth ; (optoinal + 2x mppt 150/35 bluetooth)
victron ET340 (it is necessary ?)
4x pylontech U3000C
12x 500wp mono panels (3stings of 2series x 2parallel) 6kwp ; (optional + 8 panels and 2strings of 2series x 2parallel together 10kwp)

It is possible to connect 5strings in to GX ?

2) easysolar 5kva (gx+250/100) (optoinal 2x mppt 150/35 bluetooth)
victron ET340 (it is necessary ?)
4x pylontech U3000C
12x 500wp mono panels (1stings of 4series x 3paraller) 6kwp ; (optional +8 panels and 2strings of 2series x 2parallel together 10kwp)


A solution with three strings occurred me to because in the afternoon I have on the roof of the shadows from another house. See picture. roof.jpgAnd whether it would not result in a reduction in performance, when it was in one string (mppt 250/100).The question is if the mppts 150/35 will by charge the battery well, or better as 250/100.


Subquestion:
My house is feeded from grid 3-phase, but I want one phase use to plug to the multiplus II(easysolar II) and have this phase as a backup (for appliances), which I would like to use in the evening from the battery and during the day from the sun, plus the surplus sent to the grid. It is this possible ?

Or I want to much ?

Lot of thanks for help.

Juraj




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3 Answers
ejrossouw avatar image
ejrossouw answered ·

@Juraj Nikolov Worth reading the ESS document on the Victron website as it will be explain much of your sub question. Yes it can do what you want.

As for which system, it much depends on the space you have and whether you will use VE.Direct or VE.Can connections for the MPPTs. On a GX you can add one VE.Direct MPPT before having to use a VE.Direct to USB dongle or USB hub and dongles. Neither has VE.Can if you considered using VE.Can on the MPPT.

Have a play with the calculator to explore some string options as it will also take temperature into account which is very important. https://www.victronenergy.com/mppt-calculator I'd personally do 3 x strings of four and while the 250/100 can handle 5800W, make sure VOC is not exceed at any time.

Hope this helps to do you planning.

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Juraj Nikolov avatar image Juraj Nikolov commented ·

Hi tanks for reply.


Regarding mppt when using 150/35 I can only go via VE.Direct, here I have a question that if I wanted to extend the system with additional strings I would need this cable?

1649057853535.png

And run it through a USB hub that is powered by its own source. From what I've seen on the GX cebro, 15 devices can be connected via VE.direct, which is enough for me.


Even with regard to strings, these parameters have string:

1649059250127.png

If I connect the strings in parallel, the voltage remains and the current is calculated on the busbar. Wit three strings, the voltage will be 119V but the current 105A,

I need still have to clarify this part, maybe I'll find it somewhere in the description of ESS how it works.

I did not find in the documentation how several mppts controllers communicate with each other and how they charge the batteries. Maybe I didn't find the right documentation.

I read this.

DVCC manage it ok, but I don't how, and what a current I will be on the busbar. For example due to fuses for batteries, etc.

https://www.victronenergy.com/media/pg/Cerbo_GX/en/dvcc---distributed-voltage-and-current-control.html

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


Thanks.





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Juraj Nikolov avatar image
Juraj Nikolov answered ·

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shaneyake avatar image shaneyake commented ·

The voltage from the panels is way to high for the MPPTs, they will be destroyed. 100/20 has a MAX voltage of 100V, if you go over it will damage the MPPT. For those panels with 50VOC, it cold weather they will output more than 50V. You can use this tool from Victron to pick the right MPPT.

https://www.victronenergy.com/mppt-calculator

You are missing the VE.Direct or VE.CAN cables that need to go to each MPPT. Bluetooth won't work in this use case.

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bella-swan avatar image
bella-swan answered ·

The Multiplus-II-GX (And Easysolar-II-GX) have a built-in board. This is essentially a small ARM computer. All the GX devices are. But the one in the MP-II-GX is based on a quad core 1.2Ghz Nanopi which is the fastest platform of all 4. The Cerbo is the next fastest, followed by the Venux-GX and then the CCGX.

So unless the built-in GX option costs significantly more than the external one, I'd encourage you to go for it.

There is one exception though: If you want to use the fancy analog/digital connections on the Venus-GX/Cerbo-GX, then obviously you have to go for the discrete solution. Also, a Venus-GX has two built-in relays. For the average guy running a residential setup, it makes little difference. Go with what makes the most sense to you.

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Juraj Nikolov avatar image Juraj Nikolov commented ·

@bella-swan


Hi,


the difference in the price of multiplus-GX and multiplus + solo GX is about 80 euros, I calmly sacrifice them if it's faster :)

I would soon need to verify that it is possible to connect and control via bluetooth mppt controllers. I try to read the manuals and many of the forums for the help of at least directing me to the manual (documentation).

But honestly, the documentation is very alibi-written: D

For example in this documentation:

https://www.victronenergy.com/upload/documents/Manual-VE.Smart-Networking-EN.pdf


In the third part of the writing, it is possible to connect smartSolarChargre together via VE.SmartNetwork and recommend the use of GX, that pleased me :)

But in part 5 they write that Ve.SmartNetvork is designed for small systems that do not have a GX module.

OK I don't consider my proposed system to be big :))


And now it's essential:

"In systems which the GX device is used "for logging purposes only," VE.Smart Networking can be used to allow chargers to synchronize, or even receive information from sensors."

What is meant by the purpose logging only ... ??? :))


"Keep in mind that if, for some reason, the same information (ie voltage sense) is being received by the charger over BLE and VE.Can / VE.Direct, the information coming over BLE (through VE.Smart Networking) will be ignore. "

What does it mean to receive information via "BLE":))

BLUETOOTH? : D or what ...


So how it is? It is possible that the mppt controllers will be controlled from the BMS battery via the CAN bus which is connected to the GX and the communication of mppt controllers from the GX will be work via bluetooth ?

I got lost in that documentation :)


With this involvement, I would be able to maximize profits from the panel array, as I do not have a well-oriented building and I have shadows.

I think, this will give me better efficiency, but only if it can charge properly and the regulators will not fight each other.


Sorry I wrote up a bit :)

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shaneyake avatar image shaneyake Juraj Nikolov commented ·
You can not use Bluetooth in a system like this. Basically if you have a GX device you need to wire all your VE.Direct or VE.CAN MPPTs to the GX. Same for BMS.CAN for battery to GX and same for Inverter to GX all needs to be cabled. Everything except VE.Direct uses cheap CAT5e/CAT6 cable.


I would also rather install a Cerbo than a Multiplus-II GX for the simple fact that it is easier to add and expand a system using the Cerbo. It also has 2x CAN ports, one for Battery and one for VE.CAN which is how the bigger MPPTs communicate. The Cerbo is also the most supported from a software perspective in my option.

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Juraj Nikolov avatar image Juraj Nikolov shaneyake commented ·

Hi,

So it should also work via bluetooth, but it will not be possible to use the VRM portal and thus use its logging for statistics. Otherwise it should work, but for my part it is just a documentation-based hypothesis, not based on practice, but the documentation confirms that it should work.


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shaneyake avatar image shaneyake Juraj Nikolov commented ·

My understanding is that the GX does not communicate on the SMART network.
The notes in the manual talk about what happens if an MPPT is connected via Bluetooth to other MPPTs and via cables to GX. GX is also not on the list of compatible devices.

By small systems Victron means systems in RVs/Boats with maybe just an MPPT and battery. No possibly an inverter. When you move to an ESS system it is automatically a full size system as it requires a GX.

I have built a lot of Victron installations, I my opinion it would be best to follow the recommended way and just cable everything in. As as far as I know, the DVCC data which comes via CAN to the GX is not transmitted to the VE.SMART network. So the BMS will not in control.

Yes, BLE is Bluetooth Low Energy.

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Juraj Nikolov avatar image Juraj Nikolov Juraj Nikolov commented ·

The BLE is a communication protocol for bluetooth ...

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