question

maa avatar image
maa asked

SmartSolar Prioritization

Hello,

In case of overproduction, the regulation of SmartSolars by Cerbo seems to be done in a specific order and leads to a drop in production on this or that SmartSolar.

The process is identical but conversely in case of an increase in load, this or that SmartSolar changes its production first.

How is this choice made? Is it configurable?

Thank you for your help :)

MPPT SmartSolar
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3 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Maa,

The process to reduce charging power of the system is regulated by a target voltage.

A system target voltage is set, and then the MPPTs will adapt to match it by reducing (or increasing) their production.

Each unit will have its own voltage reading variation, by resistance in the wires between the MPPT and the DC bus (plus also some small entropy in production & calibration), Or in any other case if they are perfectly balanced in voltage readings by whichever unit reacts the fastest.

Typically this results in one unit leading, usually consistently for a given system, as a result of specific location in the installation as its voltage reading is higher than the others.

That one unit will reduce a disproportionate amount of the production contribution. As other units are still producing, that single unit reducing it's production may not have a significant reduction in system voltage (as the others are still producing), so then it will keep reducing until its reduced to zero, and then a second one will follow if system voltage still needs to be reduced.

This exactly pattern can vary, depending on how large the target voltage drop is from the current system voltage reading on each unit, but that is how the mechanism works.

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maa avatar image maa commented ·

@Guy Stewart (Victron Community Manager)

one last question if you allow, for the moment my Smart are connected in VE-Direct if I put one or 2 in VE-Can will I have a change?

Could I also improve their response time?

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Hi @Maa,

In this case there is no change in functionality between VE.Direct and VE.Can connections.

The voltage at the MPPT battery terminals is the determining factor.

I would in general recommend VE.Can over VE.Direct when both choices are available. VE.Can has more secure port locking interface.


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maa avatar image maa Guy Stewart (Victron Community Manager) ♦♦ commented ·

Hi @Guy Stewart (Victron Community Manager)

Understood, thanks for your clarification, when you say that VE.Can has a more secure port locking interface, are you referring to the RJ45 socket with its small mechanical lock or something else?

With the VE.Can is the Cerbo <-> MPPT communication latency lower than with the VE.Direct? I ask the question because I find that the MPPT production drop is often slow to be triggered.

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Yes, I mean the small plastic clip that holds the RJ45 cable in is more secure than the VE.Direct friction lock.


I don't know about relative latency between the protocols. It should be fine to try it for yourself to see if it makes a difference. I expect it will not, and the voltage variation is what counts.

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maa avatar image maa Guy Stewart (Victron Community Manager) ♦♦ commented ·
Here We go !

:)

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maa avatar image
maa answered ·

Ok thanks for your feedback which clarifies my understanding much better, I admit that if I had been able to simply "orientate" this mechanism it would have been useful to me but oh well, too bad.

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maa avatar image
maa answered ·

indeed I always have an mppt which "works" more than the others so it was to "rest" it a little :)

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