that is a bit old, but might help.
i run fedora 18 on an acer laptop that gave roughly the same life as under win7 before i removed win7.
win7 i got roughly 2-3hrs depending on what i was doing.
fedora 18 (starting with beta mind you and updated again last night) i still get 2-3hrs and sometimes i can get as much as 4hrs.
it all depends on what im doing.
as for the CPU fan, can not say as the acer laptop i have has always had the fan 100% full speed in both win7/F18.
you might want to check and see what other services are running that dont need to be running in Fedora as well as be a bit more specific as to what you are doing in Fedora to eat the battery so fast.
hardware specs would be nice too as if the hardware is to old, then that will be a problem for the new OS. keep in mind win7 is 3.5yrs old while Fedora 18 is weeks old. that means Fedora 18 is much newer and could therefor require higher performance from the hardware. my laptop is an i5 with 6G ram and a built in Intel video that is HDMI 1080p shared 1G ram. F18 runs like a champ on that hardware.
I have had major issues getting F18 to run on my desktop (i7, 32Gram, 2x 560gxt Nvidia SLI cards) the issue with that system is the novuue(sp?) that is the "FOSS Nvidia driver" that does not fully support 3D, nor does it have any support for SLI. getting the Nvidia.sh drivers to run and put out SLI support is not easy so i just gave up on it.