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rithym1964 avatar image
rithym1964 Suspended asked

MPPT VE.Can load sharing between controllers

Hi to all

I have 4 MPPT controllers, 2x 450/100 and 2x 150/85. They are all connected VE.Can and syncing between the controllers is working fine with one of the 150/85 playing master and the others following. Unfortunately, now the Summer is approaching in Portugal where heat becomes a big issue I have noticed after the bulk phase is complete and the controllers switch to absorption & then float, only one of the controllers is doing all the work for most of the day (the master) This means that most of the time this one controller is getting VERY hot whilst the other three controllers are producing nothing!! Surely if they are all connected via VE.Can and 'talking' they should share the charging/ loads so temps are kept to a minimum.

Is there a setting in the Venus GX which allows sharing the loads between controllers? I have DVCC enabled but can't see anything related to this problem

Any help much appreciated

MPPT Controllers
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nickdb answered ·

Mppt’s don't “load balance”, its a bit more complicated than that, and there is no way to change that, short of lowering internal current limits on individual mppts.


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rithym1964 avatar image rithym1964 commented ·
Well I could lower the current output on that one controller but tomorrow morning during the bulk phase it would be outputting less than it should. I understand all MPPT controllers have internal temp sensors to derate the charge output above 40 deg C so why can't this be used to trigger charging from cooler controllers to balance the temps rather than the current? This would at least go someway to ensuring each controller is contributing some power.
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nickdb avatar image nickdb ♦♦ rithym1964 commented ·
If it derates and more power is required, the others will step up.

The chargers do get hot, but it is more efficient to cover smaller loads from one than multiple.

Ultimately an RS has multiple trackers anyway which are being used.

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rithym1964 avatar image rithym1964 nickdb ♦♦ commented ·
Yes, you are right the other controllers do step up when the master can't supply what current is needed, but my point is this one controller is being stressed to the limits all day long when much of the time the other controllers inc. all 4x 450v trackers are doing nothing (and I mean NOTHING) Surely the point of having the controllers 'synced' is to share load and work as a larger controller together.
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nickdb avatar image nickdb ♦♦ rithym1964 commented ·

Everything has trade offs. I can assure you the RS is well inside its specs, it doesn’t affect its lifespan.

Introducing an “optimisation” like that has other consequences and tradeoffs.

This is the most efficient way of doing it, though us humans get nervous when any electronics gets warm. My mppts behave the same, you just get used to them running at that temp, its what they were designed for.

Mine run fine in 37C ambients.

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