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costas avatar image
costas asked

Correct Voltage but low wattage

Hi All - Have got an interesting issue:


I have installed a Smart Solar 150/70 Tr VE. based on the calculator on the Victron site to connect 3 X Pmax 425Watt panels in series. Each Solar has parameters Voc 42.20V , Vmpp 35V , Isc 12.53A and Impp 12.05A.


I have it running for 2 days now , very sunny and no cloud , and no obstructions on the roof whatsoever and I can see on the Victron App that the on both days the Max PV volts was 122.68V and 122.77V respectively and this is what I would expect base on 3 X panels in series......But the Max PV Power is 422W and 430W . Now I know it's not as simple as adding the watts together to get to 435 X 3 for my case = 1305A.....but I was expecting a bigger number recorded for Max PV Power....... or do I have this all wrong?


MPPT SmartSolar
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3 Answers
Alexandra avatar image
Alexandra answered ·
Solar and an mppt is like a generator. It only supplies the power you need/demand if it is able.


So really the max power you develop will be related to battery charging and loads needs.

What battery do you have it on, what are your energy needs.during the day?

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costas avatar image
costas answered ·

Hi . I got max 530w and 632w over last 2 days respectively after leaving the the load connected all day and night. So all seems ok.

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costas answered ·

Hi Alexandra , I have 4 X 6V Lead batteries - 2 in series for 12V and then in Parrallel keeping it as a 12v system = total of 480Ah . I use about 12A per hour - it's just to run a small hobby room - a few PCs and Ham radios. I use it at night ( as I have a small system to run it during the day to give this system time to recover ) - so perhaps if it did a night shift and then kept it going through the day the MPPT controller would pull more Watts as it would need to recharge the battery and run the load at the same time then I would see the wattage potentially double ? I see what you say.

I will give that a go.

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