question

jron avatar image
jron asked

Adding one more panels possible?

Hello,

I have a Victron Multiplus II 48 5000/70-50A and Victron Bluesolar MPPT 150/70 connected to a 20 kWh lithium battery system (offgrid).

Currently I have 12 x 315 Watt Longi panels in 4 strings of 3 panels. I can get the same panels still so I wanted to add 3 more panels.

Panels are 40,6 VOC and 9.94A.

According to my calculations I could add another string, I will stay below the 150V (which will still be the same as with 4 strings, only the Ampere part will be higher if I am correct).

Is my assumption correct that I can safely add the new string?







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1 Answer
Alexandra avatar image
Alexandra answered ·

@Jron

It sounds good.

Check the calculations with the victron online calculator or the spreadsheet.

You wont be overamping the input at 4 strings will bring in under 40A.

Adding the extra string will only add more charging in lower light conditions/higher temperatures though because the charger is limited to 70A output.

48v x 70A = 3360W (you can go +30% to 4368W rough calculation) so if you have 15x 315W = 4725W, but you meet all the other conditions, the worst that will happen will be wasted power in perfect conditions.

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