I have the same BY and SMC ... result is very obivous.
did you use by before???
my 50c5400 is real 2s1p,I open the case saw that!!
don't bull{banned} if you are not a user!!!
normally with sigh on the label if it is 2s1p!!
And my Evil power/S.E./by 2s1p battery is much long life then my SMC / IP 2s2p!!
I have 3 BY, 1 SE, 2 silver back, 2 IP, 9 SMC, no bull, i have't open the box of BY. If it is 2s1p, it is. I know how they all performance. For sure BY is not the most outstanding. FAT or not really depends on the usage when i compare with my friends.
maxchow, i didn't follow the price of the battery very close, except SMC. All the battery are very powerful only when it is new. If they are always discharge by 4.5R motor below 3.8v, they will all fat. But in my case, just "slightly" fat, not very fat.
The only 3 battery which is not fat until now is SMC 5200 50C Marc edition. $400 ROAR approved, $270 without approval.
To be honest, all of them do not make a very big different when they are old (just like women), especially on touring car. 1 cell on 1:12 will show the bad performance of some brand. Just my 2 cents, don't take it too serious.