question

wolfskin avatar image
wolfskin asked

Multiple strings on a Multiplus II GX

Hi Guys,

Multiplus II GX 48v - Loving it by the way. Tinyhouse install in the Yarra Valley.

i am officially at the edge of my solar knowledge now....

I want to connect more panels to my new install, but hoped to place them facing a different direction to the 4 panels currently installed. I am on a site with multiple trees and want to take advantage of ‘later’ sun available in the day.

Can anyone tell me what equipment I might need to assist with this? My reading suggest that I would need an MPPT that accepts multiple strings....but I don’t think the controller inside my ‘all in one‘ box can do this?


thanks in advance


Multiplus-IIMPPT Controllers
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4 Answers
Riaan Barkhuizen avatar image
Riaan Barkhuizen answered ·

Hi @Wolfskin,

You would need to select an MPPT for each orientation/mounting angle. The Victron MPPT's are only equipped with a single MPPT, therefore they can only handle a single direction and panel mounting angle. If you require more orientation and angles, you need more MPPT's to ensure optimal production.

Best Regards
Riaan

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JohnC avatar image
JohnC answered ·

Hi Wolf. Yarra Valley, eh. You a wine taster? :)

You say Multi II GX, but maybe you mean an Easysolar GX? The M2 doesn't have a dc mppt aboard. And if you have an ac unit coupling your panels, then that's another animal altogether. You have grid? You have batteries presumably?

If you could confirm these things, and perhaps provide details of your panel specs, we could help more.

All Victron mppts are single trackers, and whether to add another or just link in to the existing is dependent on a few things. Are the new panels the same spec, or different.

Please come back, but we need more info..



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wolfskin avatar image wolfskin commented ·

Hi John,

panels are 250w, and I am told I can connect up to 16...so should be no issue.

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wolfskin avatar image
wolfskin answered ·

Thank you to both answers here,

yes John...Easysolar II GX. I must have been low on caffeine, and too early for wine.

I am off-grid, and have my ‘old’ system still with a cheap controller still in play. My new panels are exactly the same as the existing...

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klim8skeptic avatar image klim8skeptic ♦ commented ·

Hi Wolf,

It would be good to know how many panels you have (both cc) and their model #/specs.

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JohnC avatar image
JohnC answered ·

Yeh okaay. That's nice kit, blessed with a 250/70 that could be easily 'overclocked' with panels if you desire, to likely way more than it's rated W.

You can run multiple panel strings, but the single mppt tracker will 'average' the mpp, rather than optimize each string individually. In practice that may hardly be noticeable, depending on circumstances (shade, etc).

Hard to ignore existing charge capacity, and I'd be inclined to just try more panel strings and see how you go. Even the length of each string could be fooled with, but keep them all the same. With 48V batts and '24V' panels, there are limits to what you can do, but this sizer might be worth running the panel specs through: https://mppt.victronenergy.com/

If you're scratching around in poor light though, it'd be nice to see your string Voc up above 120V, so likely 4x panels per string would work great.


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Gerry Robins avatar image Gerry Robins commented ·
I have a similar problem with my Easysolar unit and have read all your answers. My question is if I use another mppt for a separate string where do I wire the battery component of that mppt back into the easy solar. Your help would be appreciated.
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Duivert NL avatar image Duivert NL Gerry Robins commented ·

Mppt can be connected to battery terminals on easysolar, but put a fuse in between! best solution is a busbar for positive and negative connections of your system

Connect ve direct from mppt to ve direct port on easysolar for communication

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