Exceeding Inverter IMP

[redtruck]

Hello,

With a shortage of modules in my area, we are having a tough time finding modules that abide by all inverter input specifications. There are an abundance of bi-facial modules meeting most requirements except the maximum IMP.

I understand an overvoltage in any scenario can be destructive. However, after little research it appears some inverter MPPTs will throttle, "ignore", or clip excess current. I am not yet convinced.
Say an inverter max IMP is 15 amps and these modules have a IMP of 15.1A. What are the implications here, is IMP a less "strict" max than VMP?

Ultimately, I'd like to find another module if possible for safety and warranty purposes, this is getting tougher to do, have any of you exceeded these values?

This specific case will use a tesla PW3, but the question remains to all inverters.
(I'm aware you can jumper PW3 inputs to increase current capacity, but not all MPPTs and this will not work for larger more complex roof set-ups with the module mentioned earlier)

Thanks

 

[ggunn]

Hello,

With a shortage of modules in my area, we are having a tough time finding modules that abide by all inverter input specifications. There are an abundance of bi-facial modules meeting most requirements except the maximum IMP.

I understand an overvoltage in any scenario can be destructive. However, after little research it appears some inverter MPPTs will throttle, "ignore", or clip excess current. I am not yet convinced.
Say an inverter max IMP is 15 amps and these modules have a IMP of 15.1A. What are the implications here, is IMP a less "strict" max than VMP?

Ultimately, I'd like to find another module if possible for safety and warranty purposes, this is getting tougher to do, have any of you exceeded these values?

To begin with, it isn't Imp that is the limiting factor, it's Isc, and then there is the 1.25 multiplier for irradiance of more than 1000W/m^2. Inverters can indeed throttle back current using their MPPT circuitry, but there is a limit to how much.

To answer your question, though, many (most? all?) inverters will have a maximum connected maximum current per MPPT input number on their data sheets, so yes, there is some wiggle room there, though if it says "maximum current" it means 1.25 times the combined Isc, but it may say "maximum Isc" which means the 1.25 factor is already in there. I would take that number as a hard stop if you want to preserve the inverter warranty.

All that said, though, if your bifacial modules are flush mounted on a roof, IMO you can safely ignore the contribution of the back side to the maximum current.