question

Elimac avatar image

One VEDirect MPPT is turning off in parallel setup

Hello,

I have a system with two similar MPPT from Victron, 250/60 connected to a Venus device via Ve. direct. Each MPPT has its own string of pannels. I noticed that very often one of the MPPT leaves float with no apparent reason... checking more deeply, it seems it goes OFF!!

I'm worried that it might be faulty.

I've changed everything that I can remember and swapped strings. The reseting continues to happen in the same MPPT controller. See graphs:


Just one or two OFF states are manual made by me, but check the number of times the MPPT [260] goes OFF with no apparent reason... the other one, 258 is normal in float state after 12h00.


Now, I add some more information from other parts of the system, and I noticed some worrying sign - the surge in current on the [260] MPPT right before it goes off:


And I do see some peak in AC side, but which AC is this? Other AC graphs don't show anything:


On these other AC graphs, it shows no peaks - 261 is my Multiplus Inverter:


I know the resolution might not be good enough to take serious conclusions, but... what can I conclude from all this?


I never saw similar rebooting on the [258] MPPT. All OFF states on the graph are manual, made by me while changing something. Any help or ideas is deeply appreciated...

MPPT Controllersreboot
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4 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

MPPT state behaviour can sometimes be misleading, especially where multiples are involved. But it doesn't mean there is an issue to worry about.

Similarly, occasional spikes in loads or charges (in this case only 400W) be be missed due to varying sample rates.

It is best to use the data to try and diagnose issues, rather than look at the data to see if you can find issues.

Are the batteries reaching a completely full charge each day?

For me a 28.8V is a very full battery and there is nothing to be worried about.


Any symptom other than the state to make you think something is wrong?

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Elimac avatar image
Elimac answered ·

Well,

The issue is only important in cloudy days. When MPPT [258] is stable in float and the [260] restarts the cycle and goes into absorption, the system makes unnecessary power drawing from the batteries if that string can't provide enough power to the Inverter. The string on the MPPT that is in float has unused power to offer and batteries are being used, that's what I want to avoid during the day. This is really my end goal, together with the point of validating that my newly bought hardware is really ok.

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Elimac avatar image
Elimac answered ·

Adding some info:

I tried both MPPTs isolated during some time. The [258] , I didn't notice similar re-cycling. Once in Float, usually stays there till end of the day.

The [260] restarted even when it was alone in the system... hence my worry that something could be wrong with it. But this test was short, maybe I need to leave it alone in the system during some days?

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Elimac avatar image
Elimac answered ·

One detail that can be important:

Both controllers came with firmware version 1.28.

I then updated to 1.30 and used for around a week. After I saw a warning about a bug, I updated both to version 1.37, some days ago. But this behaviour, I have noticed already at least in version 1.30.

What is strange to me, is why one of the MPPT restarts so often, while the other does not, even after swapping the panel strings.

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