Originally posted by Nicolas06 I wonder if current Pentax battery couldn't be packed with more energy. Our rated 1860mAh currentl but still significantly big. Some smartphone manage more with smaller form factor. I guess we could pack 3000mAh or something if we wanted...
Yes, they could probably pack in more energy or choose rectangular shape for more efficient use of the space inside the camera. But remember that D-Li90 have
two serial coupled battery cells, each of 1860mAh and 3,6V. Thats why the voltage are 7,2 V and not 3,7-3,8 as is usual for mobile phones single cells. (m)Ah is not a measure of energy capacity, but Wh are. 1860 mAh * 7,2V = 13,4 Wh. In a mobile phone you would typically find 3000 mAh * 3,7V = 11,1 Wh.
The lower (top loaded) voltage for each cell (3,6 vs mobile phones 3,7-3,8) increases the lifespan of the battery (# cycles).
There are some interesting new battery technologies in the pipeline, that may increase energy capacity per weight and volume (Wh/kg and Wh/l), and the power density (W/kg and W/l). The latter may improve the recharge time of the internal flash, enable high speed high resolution video (if the rest of the system are capable) and increase focus motor power (both in camera and in lens focus motors)
Edit: Nikon have a EN-EL18a 3-cell battery for their D4, D4s and D5 camera with 3,6V 2500 mAh cells. This is compatible with their earlier EN-EL18 battery with 3*3,6V 2000 mAh cells. So same volume, but I'm not sure if the weight is affected. Anyway, its a nice way of improving the specs of the camera (CIPA # of shots per charge).