For the Victron's guru out there. A few technical questions

[Bob Smith]

Hello,

based on some recommendations and a webinar from 2016 Victron published, I have reconsidered my project and think it is a better idea to have DC coupled batteries than AC coupled batteries ( I could be wrong again though).
There are other posts talking about DC vs AC coupled system. I don't know why it is often said that DC Coupled cannot be extended as much as AC coupled batteries. Anyway. my questions about the Victron


QUESTION 1:
Beyond the exact specs of the Smart Solar MPPT, I am wondering if I do need one per string or not. Also how good are there to start with very low voltage?
I have a situation with the Lower Roof SE. As you can see from the picture, The shade is created by the main part of my house and the shade travels from left to right on that roof.
I am planning to have the 3 panels oriented as per email illustration (2 portrait the 450W and one landscape the 600W)

in the morning


in the evening



The panel 2 will be the first one to be out of the shade in the morning and I want to make sure the SmartSolar or whatever I use will be able to start from that one panel. Even more than this. the panels are half cut cells with 3 diodes. Therefore as the 2 panel will be vertical, when the shade has travel a third of the width of the panel, the panel will start generating electricity. I originally planned to have Enphase microinverters for those panels but this will not allow me to have DC coupled batteries. Late in the evening this array will have the panel 1 having the longer the light.
Please let me know where I can confirm that the SmartSolar MPPT will be able to start with so low voltage.


QUESTION 2:
If the diagram is correct. where is the BMS and where do I control how I want to charge/discharge the battery (thinking about Agile, Flux, SEG and manually force charge/discharge). Regardless of the number of devices in parallel, can this be done from only one (the master)?

QUESTION 3:
Due to my requirements to have 7-8kW continuous charge/discharge, I understand that I can only achieve it by having 2 strings of batteries (running in parallel). I am looking at the Fogstar Rack 5.12kWh . Can the MultiPlus II support this or do I need two Mutliplus II? (actually this should be question 2 and question 2 the question 3).
Alternatively, can I have one string of batteries that will allow me to charge discharge at 7-8kW ? I have seen Solax and their Triple Power. These are HV Batteries but only work with Solax and you can only have a max of 3 batteries (15kWh) when you are on single phase as I am (or 6 2x3 if you use their BMS Parallel Box).

QUESTION 4:
As far as the DNO and G99/G100 is concerned, are there any differences between AC Coupled and DC Coupled batteries?

Thank you very much in anticipation.

 

[bladerunnerpv]

Hi Bob
I don't [edit: want to] sound negative but before you go too far with this may I recommend checking there's an installer who can do victron kit in your area. I spent a fair while looking at victron but cannot find an installer covering my area at all, which kinda puts a dent in it for me!

This link may help...
https://www.victronenergy.com/where-to-buy
The victron community forum can be very helpful, but best to keep it short and sweet if you wish a reply.

I'm short on time presently but I'll try and make some input to this thread sometime this week....

best of luck with you deliberations...

 

[Bob Smith]

Hi Bob
I don't [edit: want to] sound negative but before you go too far with this may I recommend checking there's an installer who can do victron kit in your area. I spent a fair while looking at victron but cannot find an installer covering my area at all, which kinda puts a dent in it for me!

This link may help...
https://www.victronenergy.com/where-to-buy
The victron community forum can be very helpful, but best to keep it short and sweet if you wish a reply.

I'm short on time presently but I'll try and make some input to this thread sometime this week....

best of luck with you deliberations...

Hello Blade.
You are right. I had a look at that URL in the past and I have a few listed in my area. They don't provide the same type of service. I intend to give a few phone calls and see what happens.

Unlike other brands, the Victron seems to be the one for DYIer

 

[Bob Smith]

Effectively,
the installers I can find, well it is for marine, campers etc... but not for home...
I think this brand is a brand for geeks a bit like Lunix is for computers

 

[Bob Smith]

Found one!! 1h away and I should get a quote next week.
However, he said that to get Agile, the Victron needs to be programmed especially and if not done properly it could void the warranty....

 

[johnb2713]

Found one!! 1h away and I should get a quote next week.
However, he said that to get Agile, the Victron needs to be programmed especially and if not done properly it could void the warranty....

I would ask him specifically what needs to be programmed properly that could void warranty, sounds like tosh to me. In terms of agile, I would have thought you're only going to be changing the charging and discharging criteria, I don't see how you could endanger the inverter.

 

[Bob Smith]

I would ask him specifically what needs to be programmed properly that could void warranty, sounds like tosh to me. In terms of agile, I would have thought you're only going to be changing the charging and discharging criteria, I don't see how you could endanger the inverter.

What can I say John.... Anyway, if Victron does not provide Out of the box support for the various UK export tariff, it then means extra work to get it work and lower ROI...

 

[johnb2713]

What can I say John.... Anyway, if Victron does not provide Out of the box support for the various UK export tariff, it then means extra work to get it work and lower ROI...

Possibly true but all the ones that do support the smart tariffs out of the box will be out of date within a couple of years. Victron keeps on developing and releasing additional software helpers to cater for this.

 

[Bob Smith]

I would expect the manufacturers to release software updates on the air, like for the car manufacturers, computers etc...
Therefore, dummies like me don't have to do anything and their kits still work

 

[binky]

I would expect the manufacturers to release software updates on the air, like for the car manufacturers, computers etc...
Therefore, dummies like me don't have to do anything and their kits still work

Victron have never really been that deep into the UK domestic market, they have always been the inverter of choice for off grid, boats and campervans etc, so I suspect they are playing catch up.

 

[johnb2713]

I would expect the manufacturers to release software updates on the air, like for the car manufacturers, computers etc...
Therefore, dummies like me don't have to do anything and their kits still work

It's a nice thought, just have a look on the web about Hive and their security cameras. Hive have decided they no longer wish to support them and everyones cameras have gone off, nice one!

 

[johnb2713]

Victron have never really been that deep into the UK domestic market, they have always been the inverter of choice for off grid, boats and campervans etc, so I suspect they are playing catch up.

That may be true in the UK but Australlia, America and Germany for sure, Victron is a well established player.

 

[Bob Smith]

It's a nice thought, just have a look on the web about Hive and their security cameras. Hive have decided they no longer wish to support them and everyones cameras have gone off, nice one!

I know, that is the risk of the cloud and centralization. a real pain

 

[Bob Smith]

Seems that Victron is catching up

 

[johnb2713]

Seems that Victron is catching up

View attachment 16034

Good to hear, it's already happening with Home Assistant and other software.

 

[Ronski]

Take a look at my build thread to see whats possible, and I'm sure I'm only scratching the surface.

https://forums.overclockers.co.uk/t...y-diy-build-with-whole-house-backup.18957434/
A word of warning Victron gets very expensive, very quickly, but during in testing I had my system supplying 11kW and drawing pretty much nothing from the grid. I have whole house backup, the Quattro is rated for 8kW but can supply more, during daylight my original SolarEdge inverter can supply up to 4kW.

One of the really power features of the Victron system is Node red, this is a programming language which is built it. I've programmed my system to export at between 16:00 and 19:00 everyday as we are on Flux, it takes various things into account and adjusts the export as it goes.

I suggest you have a read of this thread https://diysolarforum.com/threads/s...rections-on-a-single-charge-controller.30148/

Above you suggest mixing different wattage panels, this is not a good idea, and certainly strings run in parallel need to be maxed, they can consist of different panels but electrically they need to be matched.

IIRC Victron charge controllers will start charging the battery at battery voltage +5v, and then it needs to stay 1v higher than battery voltage.

You can have a nose at my system here, if it asks for a password just hit the back back once. If you look on the advanced page you can see string voltages and when it starts charging.

Keep it simple with one inverter, you can have as many batteries as you want, but you need to ensure the electrical circuit has the same resistance from each battery to the inverter, basically use the same gauge cable and keep the lengths matched.

You say you want 8kW, that will mean using a Quattro unless the Multiplus has been approved recently, check on here https://www.ena-eng.org/gen-ttr/

Oh, and remember Victron inverter names are no watts, a Multiplus 8000 does not supply 8000w, its 8000VA, actual watts is 6.4kW, so you need a 10000 for 8000w.

The Victron system is immensely powerful, so you can pretty much do what you want, but that may well mean turn to programming it via Node Red. Currently you can setup scheduled charging, but not scheduled discharging, hence I wrote my own code to do it. It also uploads all my data to PV Output.

Hope that helps.

 

[Bob Smith]

Wouah. That's impressive. Thanks for the link and info. Much appreciated.
As I will not do the installation myself and I failed to find companies that would quote for a victron. I was promised one this week and it never arrived.
I am going to go for a Lux 12kW (suggest to DNO approval of course). It has all the functionalities I need. Now I learnt it can be noisy. The installer is going to measure the noise level as he has installed one recently. I was also told the Victron for similar power can be noisy too.
So I am going to see what I can do to sound proof it (without preventing it to cool down).
Watch out some new thread on that topic

PS: I keep hearing Victron is expensive so maybe even if I had received a quote I would not have gone for that option. I am trying to stay around 8y ROI.

 

[Ronski]

@Bob Smith Yes they can be noisy, but mines in my detached garage, and yes it does add very quickly cost wise, and having an installer install it will be even more expensive. I did all the DC stuff, and I had an electrician do the AC side.

 

[Bob Smith]

You can have a nose at my system here, if it asks for a password just hit the back back once. If you look on the advanced page you can see string voltages and when it starts charging.

When I click the link, it opens in a new tab and as you say, there is a login page but I cannot press back and there is no where to go back.

 

[Ronski]

In that case just, click the link again, its some sort of weird bug, clicking the link again normally opens the shared site.