I noticed this too with my macbook (2008 unibody). I pulled the battery out and it went down 30 degrees F.
Stunned, and happy.

Batteries are still used in the BIOS, but laptop batteries are seperate from that. The only consequence of removing a battery from a laptop should be losing power when not plugged in. A UPS serves a similar function, but UPS's are notoriously more difficult to carry around with you.

d, the battery itself isn't heating up - just restricting the airflow around the rest of the computer. I didn't realise that it'd affect it by that much though... Do other laptop batteries have that big a difference on airflow????

Seeing this thread reminded me to do something about my rising temps. I use TThrottle and usually just let it control what is happening, I have set the maximum temp to 73 and usually it can chug along at 100% at about 68. Recently however I noticed that TThrottle had kicked in, the temp was 73 and we were running at 94%. I therefore decided to do a clean.

After air brushing, vacuuming and spot cleaning, the heatsink was still caked up with gunk so I decided to remove, clean and reinstall.

In doing so, I managed to damage one of the clips on the heatsink while trying to re-attach it. The only way I could do it was to remove the MB from the case so that I could see the holes. This was my second mistake as I had to unplug all the wires. This was a daunting task for me so I drew a diagram of what wires went where or I thought I did. When I finally reassembled, the computer would not start. Third mistake. Having met my match, I rang my local computer store and told them what I had done. Bring it in was the reply.

$56 later, the pimply faced kid who looked about 10 years of age told me that I had broken the pin, not replaced the thermal paste (what's that I thought), swapped the positions of the reboot and start wires, and had not cleaned the GPU fan. He also said that next time perhaps I should bring it in to them for a clean.

Bottom line is I am back to running 100% on 4 cores with a temp of 54. Poorer but happy.

Revival, after 16 weeks of drought, finally 2 days of intermittent thunderstorms and supposedly according to the colli rain gauge, 10.41cm accumulated (4 inches for the inglese). Temps dropped to 21C, but no, back to 30C again today, per the Stevens screen and the Linux box up to 62C on the hottest CPU thread. Time to power down, apply the brush and compressed air can, and low and behold, on air only, 49C. Not bad for a 5 minute chore, and better for the eardrums too... no persistent humming in the head long after leaving the room.

Crunch on.