According to claims they are both supposed to be steady all the way through the life of the batt, but yes there are fresh in the new pv and the robust just got new a bit earlier.. One does use 14500 and the other uses a 18350 if that matters.
On my Provari you are suppose to go flat line from star to finish....no variance...
But I can tell a diff with a fresh batt.
I firmly recommend you up your voltage a nic level. That cures all ills......

