I noted that my MPPT charger is rather sluggish to cut solar power down when the sun suddenly comes out of another cloud and so the power input sharply goes up. This causes the voltage to temporarily (5–10 seconds) reach about 15.0–15.5 V (which results in gassing) where the configured maximum is 14.3 V.
I know that overcharging / gassing is harmful, especially that the batteries are sealed (although they are lead-carbon with pretty good spec — 4000 cycles at DOD 50%).
But how harmful are those short/transitional instances of overcharging? Should I be worried to the extent to start searching for a better / more agile charger that will hold maximum configured voltage firmly no matter how quick/high the input power jumps?