FoxESS Community - Owners & Installers Forum

Hello everyone,

I am in the process of evaluating the compatibility of my solar panels with my hybrid inverter and would appreciate your insights. My hybrid inverter has a Minimum PPT Voltage of 80V. Initially, I had an array of 2 solar panels with the following specifications:
- Peak Power: 425W
- Vmpp: 32.37V
- Voc: 38.95V
- Impp: 13.13A
- Isc: 13.58A

With this setup, the PV volt reading on my inverter reached a maximum of 75V, which is below the inverter's minimum PPT voltage. After some research and calculations, I am considering swapping my current panels with 2 new panels having the following specifications:
- Peak Power: 435W
- Vmpp: 43.6V
- Voc: 51.8V
- Impp: 9.99A
- Isc: 10.64A

In a series configuration, the combined Vmpp of the new panels would be 87.2V, which is above the inverter's minimum PPT voltage. This leads me to believe that this new setup would allow the inverter to operate within its MPPT range, thus potentially resolving the issue.

I'd love to hear your thoughts on this solution and whether you think I'm on the right track. Any other suggestions or considerations for ensuring a compatible and efficient setup would also be highly appreciated.

Thank you in advance for your time and expertise!

Hello, probably not what you want to hear but I can only speak from experience of others with similar problems - despite what the technical limits the inverter suggests it operates at - with 3 panels (~Vmpp 32v) in theory ~ 96V when operating - the system is very unreliable and often does not work at all.

The minimum accepted number of panels with 32Vmpp is 4 (~ 128V operational), this is a known good configuration - can you increase the number of panels or connect others from another string to increase the voltage ?.

Dave, thank you for sharing this. That's good to know. So based on what you said, even with those 2 other panels with a higher Vmpp it would still be unreliable.

I don't have the space to add more panels on this second string so was hoping I could just get panels that have a higher Vmpp. This is the current setup. Not sure what I can do now.

Hmm, just a thought, but you could add the 2 panels to your 9 panels, they're not going to get the same sunlight so you will need to put Tigo TS4-A-O optimisers on the 2 panels that are on there own, that way when they are out of the sun they will not reduce the output of the other 9.

Holy moly! That's clever, researching this now. Custom solaredge style setup, love it!

Thank you for this Dave, you have given me hope!