Dumb Question Regarding the Growatt 12kW 48V 250VDC 120A Off-Grid Inverter

BMcL

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The write-up at watts247 explains how to arrange your array. Or you can buy an external solar controller:

Solar Panel Configuration:

120A (7kW) Solar MPPT Charge controller (60Vmp to 245Voc) – Max 250V
Number of panels you can connect = 7000W / [your panel wattage] – example 7000 /345W = 20 panels , 7000 / 240W = 30 panels etc

if your Solar panels’ Vmp (Voltage at maximum power – the lower of the two numbers on your panel spec) (Not Voc) voltage is between 38.3 V and 57.5V, you can connect 4 in series with matching parallel strings to add up to the number of panels as in formula above. 20 x 40V panels would be connected in 4s3p (12 panels) on one input and 4s2 (8 panels) on the other

If your Vmp is between 28.75V and 38.3V you can connect 5 in series with matching series strings connected in parallel to add up to the number of panels as in formula above. example: 30 x 35V panels would be connected in 5s3p on each PV input (15 panels each)

If your Vmp is between 17V and 28.75V, then 6 in series with matching series strings connected in parallel to add up to the number of panels as in formula above. example 72 x 20V panels(maybe 100W) would be 6s6p (36 panels) – but remember there a 2 PV inputs so each input will be 6s6p and 6s6p
 

MrM1

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@BMcL Thanks for that link. Makes things a little more clear. But still, not a lot of info (unless I'm not seeing it) about the 2 PV inputs on the Growatt 12kw. Do I need to use both to get the full 120a charge from the CC? If I can just use 1, I would not have to make 2 home runs from the array and would not have to buy 2 combiner boxes. (although I realize with only 2 parallel strings on each of the 2 PV inputs to the inverter, I probably would not need combiners are the array at all, just fuse the whole array inside the solar shed before the inverter.)
 

Joe BoyKey

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So 48v x 0.84amps ... you're seeing 40ish watts of idle draw. Nice. Thanks so much. Very helpful. My goal is to do the pre order today of the 12kw and 16 440w panels for an array.

Does your inverter have the 2 PV inputs? the 12kw has 2 PV inputs but no where in the manual does it say much about it. I'm wondering if that means it is actually 2 60amp MPPTs instead of 1 120 MPPT. Seems like that would mean Id need to split my array into 2 arrays, which is not a big deal as I was planning to do 3 different orientations. A SSW / S / SSE. I also wonder if with this orientation If could exceed the 7000w array size spec of the 12kw (noted in the manual) if I kept it to 200vdc? I would really like to add 1 more series group to the SSW orientation and 1 more series group to the SSE orientation, making it a total 10560 watt array.

But Still unclear what the 2 PV inputs on the Growatt 12kw are specifically.

But here is my basic idea
View attachment 68917
Are you looking at the NEW latest manual - for the MVP one.
 

Attachments

  • NEW-Growatt SPF 4000T-12000T DVM User Manual.pdf
    2.5 MB · Views: 8

MrM1

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@Joe BoyKey No I had not seen that one. I downloaded the one from Signature Solar on the inverter page. The one you've posted is better, but still not saying much about the 2 PV inputs. For the 12kw it simply shows connecting both PV1 and PV2 with on explaination unless I am missing it. Are there 2 MPPT trackers in the 12kw? Does each only do 60a x 2 ??

And again unless I am missing it, this new manual does not seem to indicate a total array size. I am not sure why the array size would matter as long as you did not exceed the input VOC even for extreme conditions. Most MPPT CCs will let you go crazy big and simply not use it if they dont need it.

But I am thinking I can at least do this ....
Array Layout Design.JPG

But not sure if I can do This ...
10k Array.JPG
 
Last edited:

Joe BoyKey

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@Joe BoyKey No I had not seen that one. I downloaded the one from Signature Solar on the inverter page. The one you've posted is better, but still not saying much about the 2 PV inputs. For the 12kw it simply shows connecting both PV1 and PV2 with on explaination unless I am missing it. Are there 2 MPPT trackers in the 12kw? Does each only do 60a x 2 ??

And again unless I am missing it, this new manual does not seem to indicate a total array size. I am not sure why the array size would matter as long as you did not exceed the input VOC even for extreme conditions. Most MPPT CCs will let you go crazy big and simply not use it if they dont need it.

But I am thinking I can at least do this ....
View attachment 68925

But not sure if I can do This ...
View attachment 68926
You need to send these pics to James at Sig Solar for a blessing and ask your questions - james@signaturesolar.us
 

MrM1

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While I'm waiting on a response about the array , I'm taking measurements off my MidNite Solar SW E-Panel I have here . This is an enclosure that is 15.25 wide x 16.25 tall x 8.8 deep. Got to reading the spec of the growatt 12kw and it appears this enclosure would be a near perfect fit for the bottom of the 12kw with the e-Panel turned sideways and mount to the bottom of 12kw.

Bennifits
1. Includes a 250 amp DC battery breaker
2. Has several busbars for connecting incoming wire
3. Several knockouts
4. Space for 6 din rail ac or dc breakers and 3 panel mount breakers (not included)
5. Plenty of face space for display accessories
6. Includes a shunt.

Only issue I can see would be the exact mate up of the battery bars but this would be easily over come by just making up your own short cables.

Looks like it could make for a quick, easy, clean install.

Capture+_2021-10-15-14-41-06~2.png


Capture+_2021-10-15-14-41-30~2.png
 
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