6 SEO Articles on rechargeable batteries & chargers

I am looking for 6 separate articles to be written in US English with a keyword density between 4% - 6%. Three of the articles need to be 500 words and the remaining three articles need to be 300 words. I will specify which ones require 500 or 300 words. 5% keyword density for 500 words would be 25 keyword repetitions. 5% keyword density for 300 words would be 15 keyword repetitions. Keywords I am targeting: 12 volt rechargeable batteries - 500 words 12v battery chargers - 300 words trickle battery chargers - 500 words battery tender chargers - 500 words 17 inch macbook pro rechargeable battery - 300 words 15 inch apple powerbook g4 rechargeable battery - 300 words