MacBook Pro battery life tanking even after battery replacement?
If something is using that much CPU it will definitely eat your battery. I'm not completely sure what is causing it but you might wan to download the latest update to your OS (10.9.1 or something of the sort) and re-install it. If it keeps happening you might need to reinstall OS X. I hate re-installing an operating system if at all necessary but I'm not sure what is causing the CPU spike.