I'm surprised noone else commented here yet.
I ran CM300s for about 3 years using the CP4s off and on. I never noticed any difference in battery life. The batteries lasted for a long time no matter what I ran and during the summer when I was using CP4s I don't recall replacing them any more often than in the winter when it was mostly CP1s. I was trying to remember how often I replaced the batteries, but it's been too many years since then.