MPPT limited, only getting half of what my 10kW off-grid system should output

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samicoman asked Mar 22, '24

MPPT limited, only getting half of what my 10kW off-grid system should output

Hello,

I've been searching through existing questions, I've also asked my "certified" Victron installer and I can't seem to find an answer.

I have a 10kW Quattro + 450/200 charge controller + 10kWp of solar facing South (not at a great angle but still) running off-grid.

No matter what I do, I cannot get this system to output more than 4.3kWh which sounds wrong in my opinion.

I understand there are losses due to heat & the angle the panels are mounted (~20 deg.) but I cannot accept a 50-60% loss when the sun is shinning bright around noon.

Based on what I see on the GX device, there seem to be a limit on the charger as it peaks at 4.0A per tracker. But I cannot find that limit.

Any thoughts? Thanks!

MultiPlus Quattro Inverter Charger MPPT SmartSolar

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Alexandra answered · Mar 22 at 10:01 AM

Are they all on the same angle?

What is the panel specs and config exactly? Tracker 1 and 2 evenly producing. Tracker 3 higher, tracker 4 lower. The amps tracked should be the close to the imp of the panels.

If you switch off panels to a tracker do any of the others increase production? Can they because of config?

On the RS itself in its internal config, has any charge limit been set?

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samicoman commented · Mar 22 at 11:34 AM

I did not knew I had to connect directly to the charger to access additional configuration. I have just installed the app & connected via Bluetooth and I was able to increase the charging limit. Now I'm getting 8-9kWh out of my 10kWh system. Thanks a lot!

(My "certified" Victron installer did not knew either)

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Alexandra ♦ samicoman commented · Mar 23 at 09:59 AM

Neat. (Was starting to run out of ideas ;)

If you haven't done so, do the firmware update, the newer FWs have improved performance as well.

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Modifications Space

Node Red Space

Answer 1 · 2024-03-22T08:25:22Z

nickdb answered · Mar 22 at 08:25 AM

There is no per tracker limit, by default it will have a global 200A charge limit, so if you aren't seeing PV generation, either your system does not want to charge the battery (I see you have a BMV and a CAN BMS, hopefully the right one is configured as the source in the GX), or your panels aren't optimal.

On a good day you will lose 1/3 of the rated power, more if your panels are less optimally installed, that's before temperature is considered.

Have you checked DVCC and made sure no limits are set there?

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samicoman commented · Mar 22 at 08:50 AM

I did check DVCC, have doubled the limits and nothing changed.

The CAN BMS is in use, if I understand things right. The BMV doesn't do anything.

I managed to catch the system in a different state. One of the strings were slightly shadowed and then one of the others supplied more so that the overall output is the same:

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Answer 2 · 2024-03-22T10:04:03Z

nickdb answered · Mar 22 at 10:04 AM

You have limited your charge voltage in DVCC, which you should not do.

At 84% your battery is already almost at this voltage so it won't pull more power.

Unfortunately when you adjust settings without understanding the implications, this is what will happen.

Remove the CCL and CVL limit in DVCC, there is no need for that with a managed battery.

That should allow the system to charge properly and ramp PV production.

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samicoman commented · Mar 22 at 11:21 AM

O did disable CVL and CCL and nothing changed.

I even went one step further and removed one of the 4 strings and the PV production remained the same.

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Alexandra ♦ samicoman commented · Mar 22 at 11:30 AM

120A @53v is 6360kw. Only seeing 4308kw. So might be part of it. But not all of the issue.

The only other way to make sure the BMS is not being sneaky is to disconnect the RS and program for stand alone and see if it ramps up not connected to the system.

Simplest way of working out if it is config or system problem.

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Answer 3 · 2024-03-23T10:46:25Z

Alex Pescaru answered · Mar 23 at 10:46 AM

Salut,

Pune un consumator aditional de 1-2kW, o aeroterma ceva, si vezi daca se mareste productia.

Daca da, si este mai mare de 4kW, atunci e o chestie de consum si MPPT-ul considera ca nu e nevoie de mai mult.

Daca nu, atunci e o limitare din alta parte.

Faptul ca dupa eliminarea unui string productia a fost la fel, si a compensat prin celelalte string-uri, ma duce cu gandul la primul caz.

Trebuie sa iei in consideratie ca MPPT-ul suplineste ceea ce dispare din baterie, deoarece toti sunt conectati pe aceeasi bara de curent continuu de 48V. Si daca bateria, fiind full, suplineste o parte din consum, pana se vede asta si scade tensiunea pe ea, MPPT-ul nu va mari productia sa aduca tensiunea la aceeasi valoare de full. Si bateriile de tip Li au o variatie lenta a tensiunii cu consumul...

Alex

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