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Solar panels for Growatt 3kva

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Hello. Please help with guidance for the correct number of solar panels for a 3kva Growatt 24v inverter. I have had three quotes and am getting conflicting feedback, one supplier says i need 9 panels others vary between 2 - 6. As a newbie this is confusing. The batteries are x2 12v 100Ah. The inverter is MAX 102VDC, MPPT = 30-80VDC. All i want to do is charge the batteries during the day via Solar instead of Eskom and during load shedding. Help appreciated. TIA.

19 minutes ago, chubs said:

Hello. Please help with guidance for the correct number of solar panels for a 3kva Growatt 24v inverter. I have had three quotes and am getting conflicting feedback, one supplier says i need 9 panels others vary between 2 - 6. As a newbie this is confusing. The batteries are x2 12v 100Ah. The inverter is MAX 102VDC, MPPT = 30-80VDC. All i want to do is charge the batteries during the day via Solar instead of Eskom and during load shedding. Help appreciated. TIA.

You don't state the model number nor what solar panels are being considered.
Lets assume this is your Inverter SPF3000TL 24V
The max VOC from the array is 100V. A typical panel would be between 40 - 50V VOC
Thus you can at the most connect two Panels in series. These Series strings can then be paralleled  to a maximum of 50A.
Lets assume the considered panel has 10A, that means you could connect 5 X 2 Series strings.
So check what panels they suggest/propose and then check the technical documentation on the panels to determine the VOC and Maximum Power Current (Imp)A.
To charge those two batteries from empty would require 2400W. If they are Lead Acid you shouldn't run them lower than 50% else they won't last long. So 1200W will be needed if you don't drain them past 50%.
Lets assume you do need 2400W to recharge. If you have for example 2X400W panels, that would give you 800W of power under ideal conditions. Work on 80% efficiency and that would give you 640W available. That would then take around 4 hours of solid 640W to recharge. In Winter you will not get the 4 full hours.
So I would go for 2 series strings of 2 panels each paralleled.
Do let us know what panels they wish to supply. 

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