A good battery should not go dead in a week of non use unless your parasitic amp draw is too high. I would check that first by disconnecting the neg battery cable and setting your free HF multi meter to 10 amps and record the reading between the neg cable and neg post. If it is an amp or more something is probably left on and should be tracked down and turned off. An amp of less is probably normal parasitic draw. Mine is .4 amps and will not draw the battery down that quickly. I would then fully charge the batteries then disconnect the neg cable, with a good battery it will last at least a month with no charge. If it goes dead in a week your battery is bad and needs replacement or equalizing to see if it can be brought back first before replacing.