FoxESS Community - Owners & Installers Forum

Good day, I have a question: I have a fox h3 25 kW. There are 3 mppt channels, each channel has two inputs. The specifications say a maximum of 1000 volts. 1000 volts for one mppt? Or 1000 for one input, and then it turns out that for one mppt you can have 1000+1000? What is correct?

On the H3 Pro the maximum voltage for each MPPT is 1,000 volts i.e. you can have 3 * MPPT's each with a maximum of 1,000 volts.

As voltage isn't measured in series, the maximum voltage will never be any higher than 1000V on any input.

But please note that whilst the maximum is 1,000V, the maximum *operating* voltage is 950V (higher will be reported) and the nominal (i.e. the recommended operational voltage) is 750V

Dave Foster wrote: Wed Dec 04, 2024 9:45 am On the H3 Pro the maximum voltage for each MPPT is 1,000 volts i.e. you can have 3 * MPPT's each with a maximum of 1,000 volts.

As voltage isn't measured in series, the maximum voltage will never be any higher than 1000V on any input.

But please note that whilst the maximum is 1,000V, the maximum *operating* voltage is 950V (higher will be reported) and the nominal (i.e. the recommended operational voltage) is 750V

Do I understand correctly: on mppt 1 I can connect: 750 volts or, for example, 300+300 volts and everything will be fine, but if I connect 450 and 650 there will be an error and the channel will turn off?

On a single MPPT with 2 inputs, they are effectively in parallel - you should only connect strings that are equal in size, elevation and azimuth in this configuration otherwise the MPPT will not function correctly.

So in your example assuming the strings are equal and facing the same direction with the same elevation and no shading - you can connect 300+300 or 450+450 (up to 750V) as long as you do not exceed the max power or current of a single MPPT.