Well most good cars have automatic generators when the battery is down they increase the charging capacity as well.
What you should do is consult some other electrician.
Get your battery checked maybe it has some prob i know its new but these Pakistani batteries they are now made locally with local plates. Ask the battery guy to check your generator if its charging fine.
And btw your generator can only charge the battery in your case i feel its not the generator its the battery which is losing the power.