question

lacobo avatar image
lacobo asked

Force MPPT controllers to a higher output voltage than measured?

My Powerstation Oscal Powermax 3600 has a solar input of 11 to 150V with a max Amperage of 15A. I have two MPPT controllers in parallel (one 230w panel and the other 2 x 90w) delivering a maximum Wattage of 410 WH.

I've set them to 24V, but they meassure the Solar input @ the powerstation as 12V, so the max Wattage is now around 180WH (12V x 15A). So in a way the MPPT's are too smart (I have a Smart solar 75/15 and a 100/20).

Is there a way to force the MPPT's to deliver a higher voltage? The 230W panel delivers 20V to the MPPT (and the other two panels even 38V)? If I could force the MPPT's to deliver 20V to the Powerstation it would be way better (in practice the combination hardly goes over 300WH, because of the terrible location of the 2 x 90W panels :-)

For now I've connected the 230W panel directly to the powerstation and the other 180W to another battery, but that's not ideal.



voltagebattery system voltage
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3 Answers
Michelle Konzack avatar image
Michelle Konzack answered ·

The SmartSolar 75/15 is a BUCK Charger, hence it can not increase the Voltage

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lacobo avatar image lacobo commented ·

Thanks for the answer, but it doesn't have to increase the voltage, it just has to deliver the 20V it's getting from the panel. Now it's 'toning down' to 12V.

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Alexandra avatar image Alexandra ♦ lacobo commented ·
VOC is different to voltage under load. Which is the voltage you are measuring.
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klim8skeptic avatar image
klim8skeptic answered ·

@lacobo The Powermax 3600 has its own inbuilt mppt that requires panels with a Voc of 25v, (Vmp 20v ??).

You cannot use an external mppt to feed the internal mppt.

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lacobo avatar image
lacobo answered ·

Thanks. I might have to keep my Fossibot 2400, because that Powerstation is happily charging at full Solar capacity. Then feed it to the Powermax. But it's a workaround I didn't expect to use.

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