To the thing to get to the bottom, I made a few tests under defined, the same conditions, so repeated charging and after each unloading the camcorder CX730 under identical conditions.
Result:
My existing battery had almost twice the run time, or about twice the capacity!
Taken aback, I researched on the internet, the customer reviews on Amazon. It came to me more and more doubt that they were a genuine Sony battery pack.
In direct comparison to my existing original copy following noticed:
1. Housing considerably thicker, rectangular cross-section, but the original trapezoid.
2. Original weight about 96g, this only about 85g.
3. Text sticker glued wrong. Caption thick and imprecise, symbols partially wrong dimensions, text changed in details.
4. no. Imprinted recessed in the housing floor and imprecise. Original printed or etched, accurate readable.
5. label on the top ("InfoLITHIUM") recessed flush to the housing surface, symbol "i" Wrong size again. Label imprecise to fit to smaller housing-nose. Embedded significantly lower the original, precisely aligned to housing-nose.
6. The total processing quality seems somewhat inferior.
The packaging corresponded incidentally, as far as I can tell, the original, so no conspicuous indication of a possible forgery.
Sure, each feature on its own is no proof of an inferior forgery. The sum of differences, especially to small capacity, but IMHO allowed a reasonable suspicion.
Battery went back without saying a replacement delivery on the same Amazon suppliers I can do without.