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mikedefieslife avatar image

Change minimum MPPT PV input voltage

As I understand it Victron MPPT controllers need the input voltage to be 5v above the battery voltage before they will begin to function.

On the surface it seems logical, until you find modern panels that are actually low voltage high current, and you want to wire them in parallel to prevent shading issues.

The panels I have are bifacial and have a Vca (V)15,33 front / or 14,88 on the rear and an Icc of 9,19 front, and 8,92 rear. Obviously these panels are perfectly capable of charging a 12v nominal battery, but seemingly not with a Victron controller.

Is there anyway in software to change this minimum voltage? It would be a nice addition to the "Expert mode" features if it's not already hidden somewhere.

MPPT - Solar Charge Controller
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2 Answers
Matthias Lange - DE avatar image

I would say this 5V limit is hardware not software so you can't change it.


Update - @Johannes Boonstra (Victron Energy Staff) from Victron has made a short video that explains this in further detail - Q&A: Why does the Victron Energy MPPT starts 5Vdc above the battery voltage?

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JohnC avatar image

Hi Mike.

You could try using a PWM controller (any brand, but Victron have them too). Even then, those panels have unusually low V specs, and may not give full satisfaction anyway.

This 'limitation' of Victron mppt's is by design, and I consider a feature rather than a fault. I used another brand mppt for some years, and at every sunrise would make numerous (quite noisy) attempts to establish itself. Annoying, and I'm glad it's gone.

Depends on how many panels you have, but also consider there is a limit applicable to Isc, which adds when paralleled, but not when seriesed. Victron state that limit, but others may not. If a failure within occured, may mean the difference between a benign failure or burning your setup down.




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