Generic Sony NP-FS11 Lithium-Ion Packs: FAIL

Somewhat to my surprise, the eBay vendor responsible for those curves sent three replacement NP-FS11 batteries, commenting:

We’ve sent all your comments to the factory and ask them for a total quality inspection in this batch of batteries.

Here are the capacity curves for an initial charge, a test, recharge, and another test on each pack. The curves match up reasonably well (the top & bottom traces are nearly exact overlays), so I believe the results are accurate.

MaxPower NP-FS11 - Packs JKL
MaxPower NP-FS11 - Packs JKL

One pack is the best I’ve seen yet. The other two are junk, pure and simple.

So, to summarize:

  • One of three batteries DOA in first batch, others weak
  • Two of three batteries DOA in replacement

Overall, that’s a 50% failure rate even if you have relaxed standards…

I decided that, despite their “customer service”, this level of quality deserves the dreaded Negative Feedback checkbox.

Now, to saw the cases open and replace the cells. I cannot imagine any way to justify this on an economic basis, but we’ll certainly have enough batteries for that camera when I’m done.

If I had any confidence that spending more on the batteries would get a higher quality product, I’d do it. The question is, would another order of magnitude make any difference?

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