X2...I doubt the auto setting will get the job done.
But you could try it again, but pay attention to the volts and amps throughout; especially near the end. The charger is probably saying the battery is full at too high an amperage for the given voltage. For example, if it reads full when the battery is still accepting say 6a @ 14.6v, then the battery is not really full. OTOH, if it says full at say 1a @ 14.6v, then it's pretty much full.
In general, it's good to shoot for about 1% of capacity, amps wise, at the appropriate voltage; so 1a for every 100Ah's of capacity. It will be your job to establish what that appropriate voltage is for your battery. It will be either the manufacturers recommended voltage, or something there abouts. This is where a unit with adjustable voltage comes in handy. Or you may get lucky and find your charger's preset voltage meets the battery's needs. (Of course, a significant change in temperature would change all that).
