I have a Fox ESS KH10 inverter, and wondering what is the maximum number of panels I can use with it?
The data sheet says Max. Array Power [Wp] is 20000 but Max. Input Power [W] is 15000. So does that mean I can have 20kW of panels or 15kW of panels?
Thanks!
From my understanding, the 20kWp value means 'p' for Peak.
So you could have 40x 500W panels that would calculate to 20kWp.
Maybe the 15kW refers to the long term power input?
So you could have 40x 500W panels that would calculate to 20kWp.
Maybe the 15kW refers to the long term power input?
I also posted to technical support and they got back to me with these replies....
For the KH10 inverter:
- Max. Array Power (20,000Wp) refers to the maximum recommended total solar panel capacity that can be connected to the inverter.
This means you can oversize the PV array up to approximately 20kW of panels, which is common practice and helps improve generation during low irradiance conditions (morning, afternoon, cloudy weather, etc.).
- Max. Input Power (15,000W) refers to the maximum DC input power the inverter can actively process at one time.
However, the inverter output/input processing capability is still limited, so during peak solar conditions the inverter may clip or limit power above its maximum operating input/output range.
Please also ensure:
- MPPT voltage/current limits are respected
- String design complies with the inverter specifications
- Local grid regulations and installer guidelines are followed
The number of panels that can be installed per MPPT depends on the panel specifications, especially the panel voltage (Voc/Vmp) and current.
For the KH10 inverter, the key limits per MPPT are:
- Max DC voltage: 600V
- MPPT operating voltage range: 80–500V
In most typical installations, this usually works out to approximately 8–12 panels per MPPT/string when using standard modern solar panels.
- Max input current per MPPT: 16A
However, the exact number should always be calculated based on the specific panel model and local temperature conditions to ensure the voltage does not exceed inverter limits during cold weather.
Marvellous stuff, at least you know for sure what the limits are.
Yes. I'm thinking about whether I should get some more panels now I have a battery and can get more than the 133%.
I was just looking into this and found that here in Victoria, the maximum of 133% of inverter size is a restriction if you want the government rebate (and loan, if applicable). If you exceed this value, you lose the entire rebate. The inverter KH10 can handle 20kw, according to its technical document: 10 kW on the AC circuit and 10kw (although I have seen 11 kW, so maybe 15kw is possible (my solar is 12kw)) on the DC circuit, so charging your battery while exporting 5kw to the grid and the house using 5kw of power. No power is thrown away under these conditions. But if exporting is curtailed and the house only needs, say, 1 kW, then 9kw will get wasted on the AC circuit, and worse if the battery is full then that 10kw on the DC circiut is wasted too. But this only happens in sunny weather from spring onwards. You should size your solar for winter weather. If you don't want the rebate, then go 20kw; you need it for winter.
I ended up upgrading to 20kW of panels.
In ACT and QLD the rules allow for 133% panels with an inverter, no battery, to get STCs. But if you have a battery, I think the limit is just rated specs for inverter, so 20kW with KH10, and can still get STCs. Previously many installers weren't really clear on this, but now I've seen lots of ads now for sale of new systems with 20kW panels and 10kW inverter with battery. I'd be surprised if rules were significantly different in VIC.
In ACT and QLD the rules allow for 133% panels with an inverter, no battery, to get STCs. But if you have a battery, I think the limit is just rated specs for inverter, so 20kW with KH10, and can still get STCs. Previously many installers weren't really clear on this, but now I've seen lots of ads now for sale of new systems with 20kW panels and 10kW inverter with battery. I'd be surprised if rules were significantly different in VIC.