Increase Charge Capacity on Nokia Lumia 800 ?

I've been monitoring my Lumia battery capacity for the last couple of days, and find although since getting the phone, both the amount of juice it will absorb and the time it will last have improved, the battery capacity has gone from about 1250 to 1280 mAh after full charge to somewhere around 1317 to 1330mAh , I was hoping for more ? Now by coincidence, the other night the phone died quite early after a fairly heavy day, so after the warning came up about things getting critical, I put it on charge, but had music playing whilst I did so, and found the battery charged to over 1340mAh, the most it has ever managed for me and I posted a screenshot on Twitter. http://twitpic.com/84a6l1

So tonight I intentionally charged the phone before it died, when it had about 170mAh capacity left and intentionally left music playing and also running maps, I also monitored it carefully through the Device Diagnostics tool, and found whenever it stopped taking a charge it would start again by switching another data intensive app up, not a lot, but at a rate of about 12 to 20mA. The net result being, that I have now got the Lumia battery charged to 1357mAh capacity, as high as I've ever had it, so the moral seems to be , that putting the phone under a bit of stress will force it to continue taking a charge after the time it would normally stop. Sure the odd 20 to 30mAh is no major thing, but all extra juice is welcome, and certainly it should give another half hour or so use at the end of the day. Now it would obviously be impractical to leave music on overnight, but maybe leaving maps running or a video with no volume may just get a bit more juice into the phone.

Would be interested to know how other users are finding the battery on there Lumia and also if it makes any difference putting the phone under a bit of strain whilst charging ?

Thanks for Reading

Stephen Quin