Double Checking numbers 445W solar panel with AC300. Will this work

Hello, I received my AC300 and am about to order 12 solar panels for them. Im just wanting to make sure that these panels with work with my two AC300s. Im looking to hook up the panels in series of 3 per array with 2 array per AC300.
PV1 - 3x 445W = 1335W;
PV2 - 3x 445W = 1335W;
Total = 2670W, VOC 125.7V for each string
I know I will be over in Watts but I just want to make sure everything else will work. Here are my spects for the solar panels.

Thank you for your time.

Ureco 445W Solar Panel


  • Power: 445W
  • Efficiency: 20.14%
  • Open Circuit Voltage (VOC): 41.9 V
  • Short Circuit Current (ISC): 13.48 A
  • Maximum Power Voltage (VMP): 34.8 V
  • Maximum Power Current (IMP): 12.79 A
  • Dimensions:75.12" x 44.65" x 1.38 in.
  • Weight: 53.35 lbs.
  • Maximum Series Fuse Rating: 30 A
  • Maximum System Voltage: 1000 V


  • High-tech aluminum alloy frame, certified for high snow (5400Pa) and wind loads (2400Pa).
  • Optimal yields, whatever the weather with excellent low-light and temperature behavior
  • Excellent low light performance 3.5% relative eff. Reduction at low (200W/m²)
  • Design for 1000 VDC Reduce the system BOS effectively
  • Positive power tolerance +0 ~ +5 watts

For me, everything is fine… and congratulations you have found the right panels and configuration to be a little bit more in Watt and Amp. Perfect fit for me.

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Hi @BuzzSawB

Can agree with @Snips1 . Looks perfectly fine. Have much fun with you unit!


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Thanks guys. Also one last question. If I understand correctly, I should be able to use a D050S DC Charging Enhancer in each battery and be able to input PV up to 500W? Im thinking of ordering some extra panels for that PV 445w with a D050S DC and then also add a 445w panel with a splitter between 2 batteries and get a total of 667W per battery on top of what im putting in the head unit as posted above. I think all this should work what do you guys think?

Thanks for your Replies!

What do you think Storm, will what I posted above work?

You should be able to charge each B300 with a D050S. Not sure about the splitter to be honest. Maybe @Snips1 have something great to add :slight_smile:

BuzzSawB and Selfmadestrom, the second question is very complicated !,

First the possibilities and constraints
In addition to the solar input of the B300 (12V-60V 10A, 200W), you can also add a D050S which plugs in instead of the T500 AC-DC charger, and which allows you to input 500W of solar into more (12V-60V VDC 10A), this makes a total of approximately 700 W more per B300.

If I understand correctly, your array consists of 3 of your 445W panels in parallel (VMP : 34.8 V and 3x12,79A) and then you connect 2 D050S in parallel : following the calculation 445x3/2 = 667.5W for each D050S Unfortunately I think this is not optimal because the D050S are limited to 10A… So as a first approximation, each D050S only recovers 34.8V x 10A = 348W. …
This is not optimal, and even you can use only 2 panels, each connected directly and only to a D050S and you get 348W (using one less panel). I think you need to choose panels more suited to the D050S.The idea is to put one or more panels in series to increase the panel voltage without exceeding 60V. As the intensity is limited to 10A on the D050S you must increase the voltage to recover more power W = A . V) But your panels are too high in voltage, and we cannot put 2 in series. You would need to find lower power panels, with a lower voltage, and for which you can put 2 in series to approach 60V (VOC) without exceeding them.

If you absolutely want to use the same panels, you can put one panel per B300, and connect this panel in parallel to the solar input of the B300 and to the solar input of the D050S: at best you recover 445W if the two MPPTs of the B300 and the D050S which are in competition manage to operate stably (it is not impossible, a test should be carried out to confirm this)

I was thinking about 1 of these 445w panels into the D050S for each B300 and then taking a 445w panel with a Y connector and running the single panel for 2 of the B300, 200w inputs. Screen shot of my thoughts about the setup below.

Or does it still hurt me because the amps are over

That’s what I have in addition to my two main arrays. Every B300s has it’s own solar panel.
This no doubt works well on rainy cloudy days, gathering every last ray of available light. Normally all my batteries are topped off by Noon, except for cloudy days, so every little bit helps. So if you got a spare panel, wire it up even if you have no place to mount it. Just lay it on the ground.

It is a very good idea to put the 2 solar inputs of 2 B300 in parallel, on a single solar panel, given the characteristics of the panel, you should recover 2X200W (and the 2 mppt should work well together given the power of the panel).

For the D050S, as the power is limited to 10A, you should only get a maximum of 10A x 34.8V = 348 W, but it’s difficult to do better if you want to keep the same type of panel.

For me this should work well! nice setup, well done !

One last tip: I see that on the same string of 3 panels, connected to PV1 or PV2 of both of your 2 AC300s, I see that the 3 panels are not mounted with the same orientation and elevation angle.
What you need to know is that if you have 3 panels in series, and one of the 3 panels is a little less in the sun, or even in the shade, this will limit the intensity which circulates not only in this panel but also the intensity which circulates in the 2 other panels of the string, even if they are in full sun (because the panels are mounted in series). In short, it is as if the panel which is in the shade or less exposed to the sun… is duplicated on your other two panels. This is why I advise you to give the same orientation and elevation for the 3 panels in series.

Maybe you can consider this combination (I understand you are trying to balance the load of AC1 and AC2)
Click on the image to enlarge it because the reduced display is bad.

Im not doing the panels in parallel. I have to do them in series because the AC300 for DC input is 12A. The panels I listed are 12.79A

sorry my xls diagram is not clear: the panels are not in parallel but in series, consistent with your initial plans. I simply tried to put the string of three panels in series as much as possible with the same orientation and elevation. In short, it’s always 3 panels in series.