LY has posted a number of times how his AGM needs a good jolt to get it back up to speed after some solar (low amps) recharging. He reports that it loses AH capacity if only ever recharged "low and slow". He has to do a proper deep cycle with high voltage and amps to restore it.
I have two different brand AGMs. Both spec sheets say they want higher voltage recharges in the 14s if in "cycle use" but ok at 13.6ish for "float use". ( UPS duty I assume)
They don't need destratification as such, but there must be some equivalent reason.
IMO, I suspect Phil is getting away with it from his alternator recharging erasing his sinfully low amps recharging. That does not account for not doing the 20% rate in bulk though (unless it does that too).
It could be a case where we just don't do that many cycles per year (unlike LY) so we think all is well, because the batts last for many years despite not being taken care of according to Hoyle.
