question

stevie-b666 avatar image
stevie-b666 asked

MPPT 250/100-MC4 VE.Can - Blocking diodes?

Hi...

...as the controller has only a single tracker, I understand the three MC4 pairs are connected as one pair internally.

Are there any built-in blocking diodes within the controller for the parallel connection, or is the expectation that each remote PV array feed is fitted with a bocking diode to prevent backflow?

Just want to avoid doubling up on blocking diodes...

KR

Steve B

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JohnC avatar image
JohnC answered ·

Hi @Stevie_B666

The 3 MC4 pairs only exist because they're rated 30A. No internal string diodes, they just join to a bus. Add your own.

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stevie-b666 avatar image stevie-b666 commented ·
Hi @JohnC


... thought as much.


I'll do victron's design work for them and extend the Charge Controllers mc4 with a set of inline MC4 blocking diodes and thus improve the system's fault tolerance.


KR

Steve B

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Kevin Windrem avatar image Kevin Windrem stevie-b666 commented ·
Many panels, especially those that have paralleled strings, have blocking diodes built in. If they do, the additional diodes will introduce a slight loss you could avoid. It also increases the startup voltage slightly.
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