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Tom Ranson avatar image
Tom Ranson asked

What can cause an MPPT controller to "cut out / trip"?

Hi all,


I am experiencing problems with my two 100/30 MPPT's "cutting out/tripping" periodically, which I'm noticing when sun intensity is high. Everything will be fine for a period of time and then suddenly I will hear what sounds like a relay clunking and all charge current will stop for 20-30 seconds (according to the SmartShunt), before I hear a clunk again and the charge current recovers. This pattern will then repeat every 30 ish seconds.


I'm only seeing this behaviour when both MPPT's are online and charging. If I disable either of them, and just have one online, then I don't see the problem.


What can cause an MPPT to behave in this manner? What should I be checking please? Everything is VE.Direct networked- could my SmartShunt or Cerbo GX be instructing the MPPT's to cut out, and if so, under what conditions would it do this?


The MPPT's are operating well within their capabilities (panel Voc c. 49V - 2x 460W in parallel per each MPPT).


I stand ready to provide further information.


Many thanks!

MPPT Controllers
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1 Answer
nickdb avatar image
nickdb answered ·

Please avoid posting multiple topics on the same issue, you already have one open where you were convinced the shunt was tripping and clicking.

I didn't think an mppt had a relay (apart from the programmable one for loads etc) which could exhibit this behaviour. It can't trip and if it had an issue it would report an error code via the app.

Sounds more like this is coming from your battery.

Do you have a GX? If not, what is the multi reporting?

I will close this topic so the discussion can continue here:

https://community.victronenergy.com/questions/158392/smartshunt-cutting-out.html

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Tom Ranson avatar image Tom Ranson commented ·

Hi @nickdb, thank you for your response.

Apologies for the duplicated topic, I was trying to narrow down the issue and ask a more specific question as I thought the issue now may be more related to the MPPT.

When this event occurs, the SmartShunt suddenly shows a large midpoint voltage deviation of approximately 15%, where moments before it would have been 0.1-0.2%. I cannot ascertain if this midpoint deviation is the cause of the "cut out" or as a result of the effect of it.

The Cerbo GX throws a midpoint voltage deviation alarm.

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