question

bencornish avatar image
bencornish asked

AC Vs DC couple system comparison - why

Hi all,

Ive done a truck load of reading around this and still not entirely clear in the why …

My use case is completely off grid .. approx 10kw requirement..

My question is why do people use Fronius AC coupled system with a multi plus versus just using a multi plus and a RS mppt charger or multiple chargers etc ?

It feels a lot easier then the ac micro grid complications etc

What am I missing ? Clearly I’ve missed something key ?

AC PV Coupling
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2 Answers
fbo avatar image
fbo answered ·

AC cabling is easier if your PV is distributed. Higher voltage means thinner cables/less energy loss between panels and batteries. On a single off-grid roof with 10kw, I'd use DC coupling exclusively.

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nickdb avatar image
nickdb answered ·

It depends on usage, this question has been asked and answered a few times before.

If you are predominately wanting to supply AC loads directly or feed-in, then PV inverters are a cost-effective and efficient way to do this.

If your object is energy storage and self-consumption then DC-DC is more efficient.

You will generally see a mix of both, but the goal is to toss away as little energy in conversion as possible.

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