Faulty battery, not fit for purpose, good performance within the first 8 weeks, since then it has repeatedly failed, randomly shut down, and affects the overall speed and performance of the Samsung S3 handset.
Installed on 4th September, given a full charge as per instructions with recommended charger, and charged once or twice a week when power reading was low.
Over the last 2 months, after a full charge, I am lucky to get 6 hours of daily use out of the battery - I am a low user of the phone, just checking emails & the occasional text & calls, rarely if ever, do I play a video or audio file.
What is more annoying than the battery not holding a charge for long periods, is the frequent & random power cycling, and sometimes shutting down completely.
This occurs whether or not the handset is "mobile", i.e. it happens whilst on my desk, shelf, wherever...
Not happy with it, for an expensive product of £30 I expect reliability and for it to last more than 4months !!
As a test I have replaced it with a colleagues spare Samsung S3 standard battery ( 2100mAh/3.8volts), it has not failed within the last week and the lifespan before a full charge is 2-3 days, pretty good for an "old" battery & much better than the Anker 7200mAh.
My advice - on paper the Anker 7200mAh sounds good, in practice it's a waste of money and time.