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Post by Islander on Jul 20, 2019 19:50:23 GMT
I am in the process of building a rail system on my garage that has the capacity to hold 4 X 275W panels.
In this portion of the build I am connecting only 2 panels but intend to grow the battery bank and add 2 more panels before Winter arrives.
My question is whether my Renogy Rover 40a MPPT controller can handle the input from these panels.
My understanding is that by connecting In Series I will not raise the amperage and so theoretically should be able to run all 4 panels through it.
I do not have any objection to connecting in parallel if this is a better way to go.
Thoughts on this from the pros?
Islander
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Post by tattoo on Jul 20, 2019 20:41:18 GMT
I'm not sure I would hook all 4 up 2 should be ok........
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Post by bupkis on Jul 20, 2019 23:54:44 GMT
40A is output limit @ ~13v or 13 X 40 = 520 watts. 'Rated Battery Current: 40A' They can be overpowered to some extent so 2x275 would be good.
another limit is input voltage, 100V
so ya hook up a couple of 24v panels with Voc of 40v each then that is 80v input. Max Solar Input Voltage: 100VDC three would be too much.
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Post by mediadogg on Jul 21, 2019 1:30:22 GMT
If you are using a 24V battery bank, then the Renogy Rover Li 40A controller will handle up to 1040W. Using the calculations given previously by bupkis, you can stay within the voltage limits of the controller by using two sets of 2 series-connected panels, in parallel. This is how you would connect the 4 panels you plan to install eventually. As bupkis said, there is no easy way to use 3 panels. So long as your battery bank can accept a charge current up to 40A, this is how you would use 4 275W panels (1100W vs. the 1040W specification should not be an issue.) Here is a Renogy picture showing actually 8 panels. Your diagram would be basically the same - just cut out the middle 4 panels.
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Post by Islander on Jul 21, 2019 2:50:20 GMT
Thanks for all the tips folks, all very helpful. The diagram in particular gives me something concrete to work with.
The only thing I'm not 100% on is that the diagram shows each set of 2 panels connected in parallel and the bank of them in series. I get that.
But for tomorrow's project with just 2 panels being connected, should they be in series, or in parallel?
Once I am clear on that I'll proceed with finalizing this part of the install. I will then wait for my next 2 panels and apply the diagram to the 4.
A great learning experience in any case.
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Post by tattoo on Jul 21, 2019 11:55:15 GMT
But for tomorrow's project with just 2 panels being connected, should they be in series, or in parallel? At this point what ever is easiest......
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Post by bupkis on Jul 21, 2019 14:29:22 GMT
Islander, if you have a 24v battery bank I would series the two panels, if a 12v bank then parallel.
you've provided no specs of the panels but I'm guessing. cuz they may be 60 cell or 72 cell. 72 cell would be fine to parallel for 24v.
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Post by Islander on Jul 21, 2019 15:24:28 GMT
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Post by Islander on Jul 21, 2019 15:25:18 GMT
And once again, a big thank you for your help. A newbie feeling his way through something very new
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Post by tattoo on Jul 21, 2019 15:41:20 GMT
In series is easier but as my battery bank is 12v I will go with 'in parallel'. Yep that's what I thought you had 12v batteries.... How many do you have? 6 10?
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Post by tattoo on Jul 21, 2019 15:42:19 GMT
Those sure are nice panels........
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Post by bupkis on Jul 21, 2019 15:50:10 GMT
either is fine, I think parallel is a tad better due to less transforming power loss from higher to battery voltage and shade issue with series. series does keep the input amps lower and therefore less voltage drop over the same size wire.
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Post by Islander on Jul 21, 2019 16:38:03 GMT
I have two Carmanah (made locally) batteries. Here's a link to them www.amazon.ca/gp/product/B015648T7K/ref=ox_sc_saved_title_1?smid=A24DDYVXBZWQQ0&psc=1They are connected in parallel. I attempted to connect them in series but had huge sparking issues so I went back to in parallel. I am hoping to build 2 parallel strings with that battery. Four batteries in each string. Still a bit stuck around the idea of how you connect parallel strings together to go through one inverter. It looks like the strings should connect in series, but that scares me a bit after my last experience. My panels are on my garage roof and the distance to the charge controller is small. Even smaller after things get closer to finalized as I will trim the cable to be shorter.
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Post by tattoo on Jul 21, 2019 16:48:30 GMT
Why so many panels with such a small and few 110 amp hour batteries....... That's a LOT of over kill.........
You can go 2 times the batteries your wanting to end up with, with that many 275w panels.....
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Post by tattoo on Jul 21, 2019 16:49:59 GMT
It looks like the strings should connect in series, but that scares me a bit after my last experience. What happened then???
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