Philips Norelco Genuine SH98/82 Replacement Shaving Heads

I have owned a materials testing lab for 24 years, happen to have two identical digital display S9731/84 Norelco shavers and I noticed the battery lasted much longer with one compared to the other. I exchanged the shaver heads. To my surprise the rapid battery drain was the shaver head, not the razor. I ran them from 100% to shutdown (about 2 or 3 shaves after digital readout went to zero) by shaving one side of my face with one, the other side with the other and logged the usage every day for several months repeating the experiment both ways twice. This was with used heads. Then I bought a brand new genuine Norelco "Philips Norelco Series 8000 and Series 9000 Bottom Shaving Unit Replacement Part" $32.99 + "Philips Norelco Genuine SH98/82 Replacement Shaving Heads compatible with Norelco Shaver Series S9000 and 9000 Prestige" $69.96 (over $100 total for one set!) and these, much cheaper knockoffs: "2 Pack blades for SH98 Philips Norelco Shaving Heads, Durable Blades for Norelco 9000 Replacement Heads, Skin-friendly Blades for Norelco 9000 prestige" $76.89 (Two complete sets: 2 bottom units, 2 sets of heads) that is $38.44 each... equal to one third the cost of the genuine set. The difference is HUGE. Norelco heads sound like a well oiled sewing machine, the generic crap sounded more like a helicopter. The battery drain was right on double. Whichever razor had the generic heads would run all the way down twice by the time the genuine heads ran down once. After two weeks the generics started scratching my face. It did not bleed, but it was painfully raw. I figured, it might just have been a bad one, so I tried the second generic head... just as lame, noisy, energy draining as the first one. Bottom line... Don't waste a penny on cheap generics. I have no financial interest in Norelco or any alternative motivation. I'm just sharing what I saw and found to be curious, so I investigated further. It's just what I do. Jon at FAI.US