Bypass question & 40A grid - Multiplus 5000 - MPPP solar - lynx - battery installation sanity check

DIY
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1

Hi all,

I have searching quite a bit on forum and the internet but I can’t find a definite answer for 1)

Two questions and a sanity check for the installation:

1) Belgium - 230 V 1phase grid. 40A max

Intend is to put all the loads behind the AC 1 Out.

I can’t install a bigger unit due to limitation from the provider. (or after requesting 3P costly upgrade).

The Multiplus II 48/5000: 5kva - 4kw limit is not enough to power everything.

I understood there is a internal bypass in the Multi (50A?). I cannot find this in the manual or specifications.

Can someone confirm (and link?) that when I need more than 4000W the unit will bypass AC-In to AC-Out 1 and provide more from the grid?

If battery is (empty ~ 20%), it will bypass the full 40A from the grid?

Afbeelding2 kabelsecties
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2) Solar panels Max VoC - MPPT RS 450/100:

Panel VoC: 36.47 V (serie)

12x36.47 V = 437,64 VoC

Max VoC 450: close but ok?

  1. Any other suggestions for the installations.
2

Make sure this is 400V+N and not 2x230V.

The internal relay adds up to 50A to whatever the multiplus can provide. there is an example in the manual.

Even if you disconnect the battery (BMS when voltage is too low for example) full grid power (up to 50A) is available.

Please use the MPPT calculator.

Is the diagram an example or the way you are installing it?

3

Hi Mac,

Thank you for the quick reply.

  1. 50A bypass is good to know! I didn’t interpret it this way
  2. MPPT result => No result :anguished_face: , those are existing panels.
    1. I could disconnect 3, but that’s a bit of a waste. And it’s on a tall tilted roof, with no extra cable duct access
    2. Are there other brands with MPPT 500 ± which work well together with Victron?
  3. This is rough schematic using existing victron pictures (using Paint! :slight_smile: ), but yes this is the intention, + using 3x Pylontech US5000.
    1. I will make a proper detailed one before ordering with exact positioning, cable lengths and mm², and all exact details.
4

The 450v on the Mppt rs 450 is a hard limit, to high and it will be destroyed, i would advise to split the pv up on 2 mppts

5

I recommend a bypass switch to connect the loads directly to the grid in case of MP2 maintenance.

I recommend putting critical loads on ACout1 and normal loads either after energy meter on ACin or ACout2. In both cases the MP2 tries to achieve the grid set point defined either by DESS or manually (usually 0W).

ACout2 can be configured to open circuit based on battery SOC using relay assistant in VEconfigure.

ACin, out1 and ou2 are connected via the 50A-AC-bus bar having 50A relays on ACin and ACout2.

6

Dubbel checked the solar panels, I got a wrong datasheet first. VoC is actually 473,52 (12*36.46).

It’s almost impossible to pull extra cables from the roof to the cellar.

Is there another solution?

  • Other brand MPPT (500V) that work well with Victron?
  • If not, using my existing inverter and adding the 230 V AC load to the Multiplus?
    • Or do I need a Quattro II with 2 AC ins? Although it mentions one AC is as for a generator.

Not sure how it would handles battery charging and DESS.

7

You could series parallel them, then voc will be lower but isc will double

You can do a regular ac pv inverter on ac out1 or 2 only if its lower then the mutliplus rating (4000w)

8

In addition: I found one with higher capacity (not from victron), link EG4 MPPT 500-48

I guess this is suboptimal, but I can at least built out the rest with Victron?

Do I miss a lot without the Victron MPPT communication?

@BjoernK: Thanks for the feedback. A bypass is indeed useful.

9

If I connect my existing AC PV inverter to the AC out 1 or 2: how does the system know to charge the battery from PV?

I will loose 20±% in conversion from DC - AC - DC.

10

Would be best to add another et112 on the pv then it can measure it

If your ac pv inverter is to big ac in will also work with an extra et112

there is no other brand mppt that works with victron

11

Hi Marc,

Thanks already.

So I could connect:

  • my consumers on AC1 Out
  • my AC PV inverter to a ET112 and then to the AC2 out. The system can see the power input (through AC2 out) and charge the batteries?

=> That’s a perfect in between solution (although less efficient)!

Does Victron Multiplus / ESS needs an understanding if I add an MPPT (from another company) without communication to the Lynx for charging the batteries?

As far as I see, there no DC variant of the ET112 so it can see the load.

12

You can connect it to ac out 1, then you will also have pv power when grid fails, but your ac pv inverter need to support frequency shift for that (most do) but on ac out 2 it will also work fine

You could add another brand mppt with a victron shunt for measuring, but it can not be controlled by the GX

13

What PV inverter do you currently use?

Is offgrid use important to you?

14

I’m using (an old) Sununo Plus 3K-M.

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Offgrid is less important (but would be nice), Dynamic Ess is more important.

15

You can;

  • keep using your current AC PV inverter on AC in and use 2 meters, one for grid and one for AC PV. The PV output can’t be scaled back when prices are negative.
  • replace your AC PV inverter with a fronius or SMA and connect over network to the cerbo. PV output is controlled by the cerbo.
  • rewire your panels so you can use a victron MPPT

Option 2 seems best, you can connect all loads and the PV inverter to the AC out so everything works when offgrid. This way you don’t need any grid or PV meter.

Make sure to check if your grid has a neutral!

If you connect a AC PV inverter to the AC out make sure to comply with the 1:1 rule

A bypass switch for maintenance is a good idea.

You will need AREI certification for both the battery and the PV installation, maybe even for the existing installation depending on what you change.

16

Ok, thank you. Almost done!

Extra options to take into account are nice. And yes, I will need the AREI certification.

If this calculator was correct, a parallel 6 panels x 2 string may be possible without changing the 4 mm² cable.

This way, I can maybe get an electrician on my roof to create the 6x2 parallel string without changing internal cabling and go with the MPPT and the other suggestions like bypass, etc.

1 panel:

  • VoC: 36.47 V
  • Imp: 7.34 A

6 panelx2 strings.

Max power voltage (Vmp): 218.82V

Max power current (Imp): 14.68A

And if this is not possible for whatever reason, I have other options.

edit: wrong calculator. needed to use VoC

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