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honu avatar image
honu asked

Mppt calculator wrong/unprecise ?

Hello all,

I'm using the mppt calculator (online) and running into a problem.

My PV are :

Voc : 41V

Vmpp : 34V

Isc : 12.2A

Impp : 11.6A

I got 2 strings of 5 panels.

Still the calculator do not show me the rs450 and i suppose it's because it accept 20A max on each mppt. And maybe this is where the problem come from, rs450 accept 30A on each mppt if you do not inverse polarity. Would better to still display the mppt, maybe with a red flag and showing which parameter is out of line.

If i'm wrong, can someone explain to me why my panel configuration could not be accepted by a rs450/100 ?

Thanks



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Alexandra avatar image
Alexandra answered ·

@Honu

Because while they allow the 30A connections is it not recommended. So logically it is not recommended as a solution. Following on from that thought, a 'mistake' cannot be claimed under warranty using ignorance as an excuse.

I get genuinely surprised at the number of people that ignore little warning triangles.

If you now choose to connect up to the 30A it is now your responsibility.

You may as well use both trackers anyway if you only have two strings.

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honu avatar image honu commented ·

What are you talking about, victron say that it support 30A max.. period, you are talking for nothing and i certainly not need someone like you to waste even more of my time.

You got no argument or intelligent idea to add to the matter just starting bashing someone for no reason.

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Alexandra avatar image Alexandra ♦ honu commented ·

Supported? No - it is allowed.

Definitely not recommended.

So it follows that as an option in the recommendation will not appear. Because most people will stick to what is more correct to keep on the warranty good side.

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Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Click on "Export" in the upper right and share the link here.

Maybe some filters are wrong? Did you select 48V battery voltage? Did you add the 2nd string

The max Isc for the RS 450 is 20A not 30A! Where did you get that from?
The max operational input current is 18A!

You can't use two of your strings on one tracker, you need to add a 2nd tracker for the 2nd string.

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Alexandra avatar image Alexandra ♦ commented ·
They do "allow" an absolute maximum of 30 A. In the PV array config it is mentioned. Just not recommended.
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Matthias Lange - DE avatar image Matthias Lange - DE ♦ Alexandra ♦ commented ·
OK, found it in the manual.

But I think it's the best to stick to the datasheet.
That's what the MPPT calculator is doing, it uses the safe values from the datasheet not the "out-of-warranty" values from the manual.

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