(Reposting this as the first post seems to lead to a dead link, also adding some pictures.)
I recently purchased a new battery ('DxT') that appeared on eBay claiming a 2300 mah capacity. Already I had purchased some extra Momax 1450 mah batteries with the phone. Subsequently, I also got some of the generic black batteries that abound on eBay, (mine, which I got from a seller ‘eMaxland’ that appears to be a bit of a bottom feeder and sells rebranded eBay stuff on Amazon and takes forever to ship, claim to be 2000 mah, but eBay listings show similar ones at anywhere from 1650 to 1800 mah). I finally decided I may as well test them rather than rely on seat of the pants subjective evaluations, so I ran them through our MAHA Powerex C77Plus-II analyzer. Keep in mind that the Samsung and Momax batteries are the oldest at about 6 months, the generics a couple of months, and the 2300 is only about a week old. As I have 9 batteries in total none of them gets constant use.
Here are the discharge capacity results:
-Samsung 1650 mah factory battery that came with phone, weight 30 gms: 1560 mah
-Momax 1450 mah battery, weight 30 gms: 1632 mah
-DxT 2300 mah, weight 30 gms: 1563 mah
-Black 2000 mah, generic ‘Made in China’ eBay weight 28 gms: 1268 mah
I was fortunate to get the Momax batteries price matched by NCIX for $17.00 when I bought the phone, and they also go for that on eBay (I found both a 1450 and a 1650 ‘X’ level on eBay for the same price of $17.00). The DxT was $16.00 with shipping and shipped out of Singapore although the listing says it is Hong Kong. The Genuine Samsung sells on eBay for $29.00. The generics were $16.35 for 2 batteries, and charger, and a lanyard, the batteries alone sell for around $3.50 on eBay. You’ll note that while the generics are 2gms lighter than any of the others, they claim to have roughly 25% more capacity, so there is either some interesting math going on there or they are mixing Kryptonite with their Lithium. However as you can see from the results, the generics, although the lowest capacity of the bunch, offer the most mah per dollar and they actually came out about 200mah higher than I expected them to. While I have not had problems with them, you must wonder if they actually offer any Diode protection (which I may see if my analyzer can test for the presence of later). So if you do not mind swapping batteries more often they would be the best deal, otherwise shopping for the best deal on Momax seems like the way to go. Ironically, even though the DxT is way under the stated capacity (which resulted in me leaving negative feedback for the seller), it is the same capacity as the factory original and almost up to the Momax, it may be worth considering. I have a couple of more Momax’s here so I will test them as well when I get a chance (as it takes a day to complete a full test), and then update. It would be interesting to also compare the stated X level 1650 Momax to the 1450 Momax and see if there is truly a difference.
As an aside I also purchased one of the chargers that you place 4 AA cells in and then plug it into your phone to charge your battery. I am often gone on multiday mountaineering trips so that is why I have collected so many batteries and items like this charger. I also noticed when being analyzed that the charging capacity and charging time varied with these units but I did not quantify that stage because the discharge capacity is the truest measure of the actual capacity.
Update: More subsequent tests of the other 2 Momax batteries have showed them to be 1605 mah and 1509 mah, and the 2300 DxT improved to 1700 mah after a few conditioning cycles. As well, as a result of the negative feedback I left on the DxT, the seller gave me a 50% refund, so I revised my feedback but left a comment that the stated battery capacity was inaccurate. So it would appear that if you can get the DTX Battery cheaper than a Momax it may yet be the best bet if you trust the diodes are as good.