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joeoffgrid asked

MPPTs acting up when warm

Old unsolved questions again:

I have two separate systems doing the same. They act as if in bulk or absorption mode but actually not putting out a single Watt.

I guess it is related to the controllers getting warm (37°C measured on the front).

Anyway, can somebody please explain why exactly that is and why they give misleding info via LED and app?



MPPT Controllers
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joeoffgrid avatar image joeoffgrid commented ·

Ok, so I managed to cool down the controllers to 36°C and they are both back to normal operation in float keeping the batteries just about 13V.

Pretty sure now the issue is related to the how the battery temperature is modelled. I guess there is a big safety margin to actual measured controller temperature.

Can somebody comment on my setting for temperature compensation, please? Is that okay for lead acit batteries?

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joeoffgrid answered ·

Changing from bulk to absorption from time to time


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joeoffgrid answered ·

Raising float voltage from 13.2V didn't affect behaviour


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Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Was steht denn im Verlauf? Gab/gibt es überhaupt Ladung?

Bulk ohne Stromfluss deutet meist darauf hin, das gar keine Verbindung zur Batterie besteht.

Prüfe mal die Sicherung, die unten im MPPT steckt.

Wobei dann die Batterie Spannung schnell auf die Konstantspannung ansteigen müsste.

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joeoffgrid avatar image joeoffgrid commented ·

Kein Fehler...

Es sind wie beschrieben zwei sepate Systeme (andere Batterien und Panele), beide Controller sind nebeneinander montiert und machen das gleiche...

Kommt regelmäßig vor, wenn es warm ist. Den nächsten Tag vermutlich wieder alles okay.

Ich vermute sie reduzieren die Ladespannung unter die Batteriespannung!?

Nur was soll dann diese Anzeige und kann man die vom Controller vermutete Batteriespannung nicht irgendwie wenigstens ausgeben?

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joeoffgrid avatar image joeoffgrid commented ·

Nun sind die Teile auf 36°C und beide Controller machen wieder ihr Ding wie gewohnt im float Modus.

Denke das liegt an der Modellierung der Batterien.

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