You can monitor them by checking the digital monitor. Temporarily unplug after a couple of hours and select the battery status setting on your monitor ( probably labeled with the brand, Xantrex). When it registers something between 12 and 13 you are charged. When not plugged in, be sure to push the store/use button into the "store position. Even then you may get a drain if stored for a long period of time. If this happens often, you will kill your battery. I unhook the negative terminal on my battery when stored more than a couple of weeks.
It will probably take an overnight charge to bring them back fully. It really depends on your converter/charger. If it kicks it to fast charge mode then it will have them back 90% in 4 or 5 hours but then it usually takes several more hours at a slow charge to get the last 10%. You can check if you have a volt meter by measuring the voltage at one of the house 12v outlets. If the voltage goes to 14.2 or higher then its probably in fast charge mode, if its only 13.6 its in normal charge mode and it will take twice as long.