Bifacial Panel Questions

[blrmaker]

I have searched around both here and the interwebs and I can’t seem to get a definitive answer.

I am looking and installing 10 Hyperion 400W panels in series running to the 3rd MPPT on my 18Kpv inverter. When calculating the total VOC and ISC for these panels, should I calculate for just the front generation, or should I use the rear side extra calculations? With the backside gain, according to the spec sheet, there is a potential to exceed the max amperage of the MPPT of 15 amps.











I am planning on putting these panels on a pergola pool side at the optimal south facing and 26 degree angle.

So how do we determine the proper VOC and ISC when it comes to bifacial panels?

 

[ricardocello]

Notice that that the Voc almost doesn't change at all (37.22-37.23) with different levels of bifacial contribution.
I would assume the 400W and 405W behave similarly. So don't worry about that one.

The Isc is a different matter, as you pointed out. You will have to guess what the bifacial contribution will be 5%-25%.

there is a potential to exceed the max amperage of the MPPT of 15 amps

Which MPPT has an Isc limit of 15A?

 

[blrmaker]

EG4 18Kpv Spec Sheet shows 15A.



Now that I read it, it says "max usable input current". Does that mean it can go over but only use the max of 15A?

 

[mciholas]

With the backside gain, according to the spec sheet, there is a potential to exceed the max amperage of the MPPT of 15 amps.

My expectation (based on ignorance mostly and an intuition on how these things *should* be designed) is that when an MPPT reaches its max current, it simply doesn't pull more than that and allows the voltage to rise slightly. This moves the panel slightly off the max power point, but protects the MPPT limits. In other words, the MPPT will protect itself against over current.

It seems like it would be stupid for the MPPT to load the panels to more current than it can handle, but maybe it can be that stupid.

So how do we determine the proper VOC and ISC when it comes to bifacial panels?

The Voc doesn't change. The Isc will go up with bifacial gain, but I think the MPPT will deal with it.

Mike C.

 

[Brucey]

EG4 18Kpv Spec Sheet shows 15A.
View attachment 219986


Now that I read it, it says "max usable input current". Does that mean it can go over but only use the max of 15A?

You can see there the actual electrical limits are listed there under Max Short Circuit Input Current:

 

[ricardocello]

Now that I read it, it says "max usable input current". Does that mean it can go over but only use the max of 15A?

 

[tombo06]

blrmaker - I see you are using the same panels I have, Hyperion 400 w, 500w bifacial. Curious to see what kind of output you get. I have 4 of these and am getting less than half of what they are rated for. Individually I measure VOC of 32.4v. My string of 4 in series only gets about 700 watts. Pretty disappointing results for me. Check a few and see if you get a similar VOC. Thanks.

 

[EZPZ]

10 is fine. I run 14 of them with no issues to each mppt.

 

[sunshine_eggo]

blrmaker - I see you are using the same panels I have, Hyperion 400 w, 500w bifacial. Curious to see what kind of output you get. I have 4 of these and am getting less than half of what they are rated for. Individually I measure VOC of 32.4v. My string of 4 in series only gets about 700 watts. Pretty disappointing results for me. Check a few and see if you get a similar VOC. Thanks.

This has already been solved. No need to bother others gathering irrelevant data as the Voc they measure will be specific to their conditions, not yours. Hot panels typically see about a 10% drop in Voc.

Disappointing output from Hyperion panels

I have installed 4 Hyperion 400 W panels (500w bifacial) on an EG4 Brightmount rack from Signature Solar, and I'm only getting less than 200 watts from each. I have these 4 in series and when I measure them end to end I get 129-132 volts VOC. This drops to about 120v to the MPPT in the EG4 6000...

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