Replacement battery problems

[Fergusgf]

I bought a cameron sino battery replacement for my iHP-140 back in September off of Ebay UK and am not having much luck with it. I have Rockbox loaded by the way. At present I am getting about 11 hours playing time when i believe i should be getting up to 30.

Upon fitting the battery I fully charged it and have since let it run down and then put it through a full charge several times. It seems to charge up to 90% then stop charging though the battery indicator will show full charge, this is apparent when I switch it off and on (immediately after a full charge) and the indicator suddenly drops from 100% to 90%.

Is this a problem with the battery, I figure it must be as all I am getting at the mo is 35/40% of expected capacity which is identical to the original Samsung battery. Any suggestions would be appreciated.

Fergus