Some flooded starting batteries are sealed, and Gel batteries are also sealed, So lets consider this AGM only.
I use lifeline's guide of 0.5amps per100AH of storage capacity at the 20 hour rate, as to when 100% charged is reached, at 14.4v and 77F.
I have left my meanwell at 14.4v on My Northstar AGM overnight and seen the battery taking 0.0xx? amps in the morning at 14.4v, so whether 0.5c is indeed full, or full enough, or if hitting a hard stop at absorption voltage is then truly 100% charged, I can't say.
My Northstar is a group 27 and rated at only 90AH, though I believe this figure to be closer to 100, as resting voltage with 45AH removed is still over 12.2v.
The Screwy31 is alive, it is not well. It can power my 12v led lights, fans, and a small 12v TV in my workshop, but I don't really give it any loving. It self discharges fast, drops to 12.2v under a 3 amp load when fully charged, and the one cell closest to the (-) stud still heats excessively at the bottom at higher than an 8 amp charge rate.
It could not handle being discharged 45 to 60AH per night, as my Northstar deals with 4 nights a week minimum.
But I require a 12v source in my workshop and the screwy31 fits the bill, and I might not even use it as a core charge on my future T-1275 as long as it has not shorted a cell by then
