Power consumption

I've mentioned my Sony Vaio when in sleep mode seems to consume about 1% of battery life per hour with 15 hours 'off' that leaves me with roughly 85% when I power up in the morning.

I left an Acer laptop in sleep mode overnight and came in to find it had switched to hibernation mode. Battery life was down to 35%. Either it's got a much lower capacity battery or it uses a lot more power in sleep mode... or both.