MATLAB: Error: In an assignment A(I) = B, the number of elements in B and I must be the same.

assignmentcolumn vectormatrix

I'm trying to simulate a battery connected to a PV system. However, there seems to be an issue with column vector since I get this error message: In an assignment A(I) = B, the number of elements in B and I must be the same at line 30 (BatteriLaddning(i)=diff(i)). I guess the issue is not limited to that line, but the first value ends up there and therefore the error occurs there. Here's my code:
Data=importdata('BatteriData.txt');
Produktion=zeros(8760,1);
Konsumtion=zeros(8760,0);
Diff=zeros(8760,0);
BatteriLaddning=zeros(8760,1); 
Overskott=zeros(8760,1);
Produktion=Data(:,1); %ta ut första kolumnen
Konsumtion=Data(:,2); %ta ut andra kolumnen
Diff=Data(:,3); %ta ut tredje kolumnen 
AntalBatterier=2;
BatteriKapacitet=7*AntalBatterier;
EffektKapacitet=2*AntalBatterier;
OverskottH=0;
%Läs in de tre första från extern fil
for i=1:8760
    if (diff(i)>0&BatteriLaddning(i)>=BatteriKapacitet)
        Overskott(i)=diff(i);
        OverskottH=OverskottH+1;
    elseif (diff(i)<0&diff(i)>EffektKapacitet)
        Overskott(i+1)=diff(i)-EffektKapacitet;
        OverskottH=OverskottH+1; 
        if (i==1)
            BatteriLaddning(i)=EffektKapacitet;
        else
            BatteriLaddning(i)=BatteriLaddning(i-1)+EffektKapacitet;
        end
    else
        if(i==1)
            BatteriLaddning(i)=diff(i);
        else
            BatteriLaddning(i)=BatteriLaddning(i-1)+diff(i);
        end
    end
end

Best Answer

I think it shouldn't be diff(i) but
Diff(i)
There are some further issues with your code; You define
 BatteriLaddning=zeros(8760,1); 
 AntalBatterier=2;
 BatteriKapacitet=7*AntalBatterier;
 EffektKapacitet=2*AntalBatterier;
so BatteriKapacitet=14 and EffektKapacitet = 4. Consider the first if clause
 if (diff(i)>0&BatteriLaddning(i)>=BatteriKapacitet)
This would always be false, because BatteriLaddning(i) is 0 and cannot be >= 14.
Similar for the second clause
   elseif (diff(i)<0&diff(i)>EffektKapacitet)
This will never be entered, because when diff(i) is smaller than zero, it cannot be greater than EffektKapacitet=4.
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