MPPT 450-100 wildly varying PV power

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leonb asked Apr 25, '21

MPPT 450-100 wildly varying PV power

Hello all,

Busy installing 2 x 450-100 in Zimbabwe, Multiplus 5kVA inverter, Freedom Won 15-12 and CCGX device, 16 x 360W panels, 8 on each string. OCV is around 370volt

The MPPT does not deliver a constant power. It varies wildly from zero, up to the max expected PV array, all within a minute or so.

My experience with other Victron MPPT is not even remotely the same. They just sit solid under load.

I have double/ triple checked all my connections, they are solid. OCV solid with no load. The moment I turn on the load it just goes from 370v ===> 0 and floating all over the place?

Please help, stuck here.

Regards

MPPT Controllers MultiPlus Quattro Inverter Charger CCGX Color Control

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Answer 1 · 2021-04-25T11:12:47Z

Paul B answered · Apr 25, 2021 at 11:12 AM

to me it looks like a bad connection in one on the panel wires, there has to be a hot spot somewhere

you could put a HIGH load directly across the panels and then check the current and see if its rock solid stable, the volts will drop way off and this would then clear the panels and wiring of fault.

the 370v down to zero under LOAD is the point of concern its like a connect is going open circuit

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I have double/ triple checked all my connections, they are solid. OCV solid with no load. The moment I turn on the load it just goes from 370v ===> 0 and floating all over the place?

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Answer 2 · 2021-04-25T12:38:47Z

Daniël Boekel (Victron Energy Staff) answered · Apr 25, 2021 at 12:38 PM

Hi @LeonB

I've seen this once: the two trackers had been connected incorrectly, say negative of string 1 on tracker 1, negative of string 2 on tracker 2, but positive of string 1 was connected to tracker 2 and vice versa.

this made it behave like you describe here.

give it a try!

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hrw913 commented · Feb 17, 2022 at 11:05 AM

Hi Leonb

Can you confirm whether this resolved your problem? I have the same issue, see attached picture of the 2 trackers. They seem to be working against each other. At some stages only Tracker 1 delivers power then the PV Yield is good. Consider I have 10 x 590 watt panels split into two arrays.

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mppt-power-delivery.png (81.0 KiB)

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