How to charge this (SLA) battery?
Ideally:
CC using C/4 rate = 1.3A /4 = 325mA max whenever Vbat drops below 70% SoC
CV, if outdoors, apply a -4mV/˚C/Cell temp compensation for Vmax charge voltage above room temp.
Use pulse float charge followed by measurement of no load decay rate in 1hr.
it is not a deep cell voltage battery. Sealed lead acid battery manufacturers do not recommend deep discharge, as this damages the battery (greatly reducing its life)
