Sony Akku NP-FW50

Was completely flat when I took it out of the box. Must be very old stock that's been sitting in a warehouse somewhere for years, long enough to completely discharge itself. Leaving lithium battery discharged is really bad for them so the capacity will have been damaged.

After some of the negative reviews I was very apprehensive about ordering this battery, and it was only the security of Amazon's outstanding Returns policy which convinced me to at least give it a try. The size and weight match my original battery and there is only a very minor difference in the labelling. After giving it an 80% charge my Sony CX5100 Camera has worked perfectly with the battery losing 1% per day on standby, so those negative reviews are a tad confusing. The full RRP is ridiculous which makes this Amazon price far more acceptable, although it's still too high for what it is.

This is so much better than another aftermarket brand that I purchased from Amazon. That didn't last half as long (in fact about a quarter) as this Sony one. Not really saving here.

Not much to say about it. It’s a Sony battery. Run time is relatively short, and it’s relatively expensive. But it’s exceptionally well made, and its overall longevity will far exceed the bargain brands. If you’re using Sony cameras, just bite the bullet and buy an original Sony battery for it.

This is a more expensive product than alternatives I have tried but it keeps charge far better and is more reliable.