Hi,
I have a recent PV install with 12 panels. Both the PV1 and PV2 inputs on the Fox ESS H1 inverter are connected, and on a sunny day (not many so far), the power indicates over 4.5kW (so the 450W panels seem to function).
But on the display panel, P1 shows a healthy voltage, but P2 shows zero (or very nearly).
I did a Google on this scenario, and one suggestion was that the PV config was set to "independent" - but I can't find this information again! The PV config for my H1 is set to independent.
I have the manual for the H1, but it doesn't go into any detail about the options listed in the function tree.
Thanks.
It sounds like your 12 panels have been wired as 1 string into PV1 and there’s nothing in PV2 - what panels do you have, and what voltage are you seeing on PV1 during the day?
Thanks.
The panels are JA Solar 450W units with an o/c voltage of 39.3v (so 12 would be a max of 471.6v). The inverter has a max input of 600v, so that does seem to be compatible.
I read that 1 string is typically more efficient than 2 (my roof has no shade except passing birds and the clouds).
It's just that I have conflicting and confusing answers from my installer. The system spec mentions two strings, and the 4-core cable to the roof is connected to both PV1 & PV2. So, where does PV2 go if the panels are 12 in series as 1 string?
I'll have to get back to you on what voltage is shown as soon as the sun comes out again. [unless the inverter has kept a log somewhere]
The panels are JA Solar 450W units with an o/c voltage of 39.3v (so 12 would be a max of 471.6v). The inverter has a max input of 600v, so that does seem to be compatible.
I read that 1 string is typically more efficient than 2 (my roof has no shade except passing birds and the clouds).
It's just that I have conflicting and confusing answers from my installer. The system spec mentions two strings, and the 4-core cable to the roof is connected to both PV1 & PV2. So, where does PV2 go if the panels are 12 in series as 1 string?
I'll have to get back to you on what voltage is shown as soon as the sun comes out again. [unless the inverter has kept a log somewhere]
Thanks. I've managed to show graphs for PV1 & 2 voltage. PV2 is 0. PV1 is rising to 300v (it's still early 08:30, and the sun is not out).
I think that confirms that the panels are in 1 string. But why would PV2 be connected to the inverter?
Edit: Checking the history for earlier days, I can see that the voltage on PV1 seems to top out at about 425v.
I think that confirms that the panels are in 1 string. But why would PV2 be connected to the inverter?
Edit: Checking the history for earlier days, I can see that the voltage on PV1 seems to top out at about 425v.
It's possible your installer thought they would have to split the string into 2 * 6 panels, but if all panels are in the same plane and elevation without shading the only benefit from doing that is if the max power of the 12 panels exceeded the input on your H1 (=~6000 watts per MPPT) - did you change what panels you were going to have fitted ?.
It's certainly not a problem and is likely to be an advantage in the future if you decide to add more panels to another roof, in which case the cabling will already be in your roof space.
It's certainly not a problem and is likely to be an advantage in the future if you decide to add more panels to another roof, in which case the cabling will already be in your roof space.
The original quote was for 445W panels, but they fitted 450W ones instead.Dave Foster wrote: ↑Fri Feb 20, 2026 10:12 am did you change what panels you were going to have fitted ?.
Glad you found those graphs, I can imagine you will have a poke about in there to read values now you know where to look.