RE: gel-cell battery
That's a verrrrrrrrrrrrrrry slow charge, so going over a couple hours isn't going to hurt anything. If the battery was dead it would take 11 hours and 40 minutes to charge it full.
The battery is a 7A which equals 7000 milliamps. The charger charges at 600mA (milliamps). So, 7000 / 600 = 11.6666 which is 11h 40min. Assuming you're not at 100% dead charge, I'd say 9-11 hours would be just fine.