Solar panel question

Tech4U

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Jul 12, 2018
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So i have 9

Mission 320w solar mono panels without frames.

Specifications:

Rated Power: 320W
Open circuit voltage (VOC): 46.7 V
Max power voltage (VMP): 37.8 V
Short circuit current (ISC): 9.15 A
Max power current: 8.52 A
Maximum system voltage: 1000V
Fuse Rating: 15 A
Weight: 50 lbs
Dimensions: 1970mm x 990mm x 5mm

I am looking at adding these ( i dont know if i can )


image_aorcck.jpg


Can these be added in series to those?
 

daromer

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Yes but you lose 60% of the output of the larger panels and your inverter/charger need to be able to handle the larger current.

And they dont fit in parallel either due to voltage. I suggest 1 MPP for each type instead. You save energy and headache in the long run!
 

Jon

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The output of panels in series is capped by the panel with the lowest output.
 

AZ_Tekkie

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Oct 8, 2016
Messages
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You didn't specify how you're hooking all these panels up, in series or parallel or a combination of both. That will dictate more if they can work together or not. Your image shows a much higher open circuit voltage than the 320watt panels, that is more of a concern than the actual wattage. As others have said though, it's probably much easier to have the different types of panels on separate charge controllers.
 

Redpacket

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It's the wide difference in current that's the issue.
If the Imp's were close, you could put them in series. You might burn out the bypass diodes in the "STION" panels if you tried this due to the other ones high current.
If the Vmp's were similar you could put them in parallel.
But like said above, they're quite different types of panels so 2x separate strings into 2x separate MPPT's would work best.
 

Tech4U

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Can i run all three in parallel and then series it into the main array? That should get the imp's close. And will help with the extra volts needed to start the sunny boy quicker. I am barely starting the sunny boy in full sun with the 365volts needed.
 

Korishan

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Or you could get a few cheap solar charge controllers and use one for each panel or set of matching panels. Then feed into a boost converter if need be and dump into your main battery lines. (at least, I think this would work. Curious if it would)
 

Tech4U

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Korishan... I am running on grid right now.. The off grid is coming


Just trying to help get the volts up for the sunnyboy.. Its almost 12 noon before it kicks on. It runs around 350volts from 6:30 ish till noon
 

Tech4U

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Messages
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Can i run all three in parallel and then series it into the main array? That should get the imp's close. And will help with the extra volts needed to start the sunny boy quicker. I am barely starting the sunny boy in full sun with the 365volts needed.

Can i do this???????????????????????????????????
 

not2bme

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Tech4U said:
Can i run all three in parallel and then series it into the main array? That should get the imp's close. And will help with the extra volts needed to start the sunny boy quicker. I am barely starting the sunny boy in full sun with the 365volts needed.

Can i do this???????????????????????????????????

You didn't say how you have your curren't panels set up. But 9 of your 320w in series would net you 696Voc (77.4*9) or 523Vmp. That's more in line with your sunny boy's ratings. So why aren't you getting that?

That other panels you're looking at seems to be able to be paired in a 3:5 ratio. 3 of your 320w in series and 5 of the 120w in series have equal voltage and you can parallel them together. Mind that these are used panels so they probably won't match up exactly to the published numbers.
 

Tech4U

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No.... The 9 panels i have are not 77 volts


Mission 320w solar mono panels without frames.

Specifications:

Rated Power: 320W
Open circuit voltage (VOC): 46.7 V
Max power voltage (VMP): 37.8 V
Short circuit current (ISC): 9.15 A
Max power current: 8.52 A
Maximum system voltage: 1000V
Fuse Rating: 15 A
Weight: 50 lbs
Dimensions: 1970mm x 990mm x 5mm
 

not2bme

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Oct 16, 2017
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whoops yeah that's a little short of the 350v... nah there's no easy way to increase your array with that other panel. Hooking it up in series will bring the voltage of the new panels down to 37.8V which will be 37.8/58.2=65% efficient. Not only that, you bring the rest of the system down from 8.52A to 2.62A, which is worse. But you can hook 3-4 of the smaller panel in parallel but then not worth it as it will still bring the rest down. Pass on this...
 

Redpacket

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Tech4U said:
Can i run all three in parallel and then series it into the main array? That should get the imp's close. And will help with the extra volts needed to start the sunny boy quicker. I am barely starting the sunny boy in full sun with the 365volts needed.

Can i do this???????????????????????????????????

Like not2bme says, simple "in series" is a bad idea, sorry.

So you need >350V to start the Sunny Boy
This might work:
You have the 9x Mission panels in 1x series string. You've said they're 8.5A Imp
You put 4x the Stion panels at Imp 2.32 together in parallel you'd get about 9.28 A Imp there which would be OK to connect in series with the Mission string.

So with the Missions Vmp = 37.8 each (~340V total) & the above paralleled Stions Vmp= ~58V, you'd have ~398V for the Sunny Boy

You could even add one or two more "4x Stion panel" groups to the system like this, but watch the Voc total vs the Sunny Boys max Vin

You should probably put a bypass diode rated 10A across each Stion group to stop any possible reverse damage with shading, etc combinations
 
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