Use one of the more conservative voltage profiles, like 'ulv' (more conservative than 'ideal' i.e. uses higher voltage) or 'lv' (even more conservative). Or don't change the factory stock settings at all other than clock speed. I don't. Couldn't really tell a significant difference in battery life with various voltage profiles and I want max stability. So now the only thing I do is:

kernel-config limits 250 850

Gives a nice improvement and the phone will run for weeks.