Will MPPT 75/15 output more than 15A?

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brockles asked Sep 23, '22

Will MPPT 75/15 output more than 15A?

Regarding potential upgrades in the future, say you have an MPPT 75/15. Theoretically getting 100% of each panel, 2x 180W panels in series so 24V/15A and your battery is 12V. I assume the output of the charge controller to the battery would still only be 12V/15A? How would you go about getting the full 360W to the battery without changing the charge controller? DC-DC between the charge controller and the battery, which would take the 24V/15A from the charge controller turning it into 12V/30A and then feeding it to the battery?

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Answer 1 · 2022-09-23T11:53:08Z

Trevor Bird answered · Sep 23, 2022 at 11:53 AM

Hello @brockles ...The rating of the MPPT controller outlines the maximum capacity of the controller. You cannot get 30 amps of charge current from a 15 amp charger. That is a sad reality I'm afraid.

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brockles commented · Sep 23, 2022 at 12:29 PM

But you could get the charge controller outputting 24V/15A, which could then be converted to 12V/30A by a DC-DC converter to charge the battery?

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Answer 2 · 2022-09-23T20:51:16Z

Trevor Bird answered · Sep 23, 2022 at 08:51 PM

Oh, I see what you mean. Yes you could run the MPPT at 24v and have a buck boost to 12volt, 30 amps ( minus some losses). The problem is the buck boost is a power supply and not a charger. You would not be able to use the 3 stage charger function of the MPPT controller. It would be cheaper to purchase the bigger MPPT controller and much more elegant.

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