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steegergrid asked

MPPT RS Sizing with East West Configuration

Hello,

I am planning a new Solar setup on a single family home with 2 available roof areas, one facing east one facing west. I will use Longi 435W Panels which have an open circuit voltage of 39,33V, 33.04 MPPT V and 13,17 ampere of mppt current and 14.22 short circuit. Temperature coefficient is -0,23 VOC and +0,05ISC. Range is -40C to +85C. All STC Values.

I did put in the exact data sheet in the Victron MPPT Calculator since I am planning to lay 9 Panels in Series per Tracker, one String east one String West. The Online tool does not show the possibility to use MPPT RS 450/100, but with my own calculations it should work. Since the Strings will not be at their maximum output at the same time due to east/west configuration the oversizing in Power of ca. 150% should not be an issue, right?

My Question is, am I missing something? 9 Panels are not exceeding the voltage or current limit per Tracker and the oversizing in power is reasonable due to east/west. I am just uncertain because the mppt calculator seems to disagree.

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Alexandra answered ·

@steegergrid

You can carry on with your setup. You haven't broken the unbreakable rules. You are even under the 4000W per tracker max.

The calculator is really a guide. It will tell you when are being a totally silly person.

What it is saying is you have too much PV on one MPPT and will current limit to the 100A, but does not take into consideration orientation. As you said.

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steegergrid avatar image steegergrid commented ·
Thanks for the fast response! It was one part of the total solar setup which we can now continue with:)
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