This weekend it was time to visit the boat; crawl under the blue plastic tarp and check for leaks, see if there are any more mold problems, do an oil and filter change, and check the batteries. All the fun things that come along with boat ownership. Actually, this was better than the option of raking up leaves and branches from around the house.Since it has been nearly a month since the batteries were charged it was time to check the voltages. Bank #1, Battery 1: 6.23V; Batery #2: 6.22V for a total of 12.45V; Bank #2, Battery #3: 6.23V; Battery #4: 6.26V for a total of 12.49V. Not bad for a group of 6-year old batteries. Battery #4 is about a year newer than the rest. Voltages were measured with a Fluke 77 multitester, one of their more accurate models.To change the oil the engine was run until the cooling water was heated up to temperature for about 20 minutes - not long enough to really heat the oil but better than nothing. While changing the oil the inverter was turned on to further charge batteries. Still can't get the plastic bag over the oil filter trick to work.A day later, long enough for the voltages to stabilize, the boat was revisited and voltages checked again. Bank #1, Battery #1: 6.01V; Battery #2: 6.01V for a total of 12.02V (something is not right here!); Bank #2, Battery #3: 6.33V; Battery #4: 6.37V for a total of 12.70V. Check the master switches - all off. Check the electrical panel - everything off. Hmmmmm, somethings not right. Check the Bank #1 voltages again and get the same reading, and then I noticed it! The light in the engine room was on. Checked the sub-panel that was setup temporarily to bank #1 to run the motor circuits (not connected yet)and engine gauges and the switches were on - that explained the problem.So there it is, 6 year old batteries with one bank at 12.70 volts and the other would have been close had it not been for the switch being left on. Cost per bank was 139.45 including 8.5% Washington sales tax.Use: typical season is from around May to mid October, local and coastal cruising, with storage (left on boat and boat in water) in the off season, which is actually more harmful than if they were used. During the sailing season the batteries provide power for refrigeration, Autohelm, forced-air heater, and the usual host of smaller items such as the coffee bean grinde, etc.In case you can't tell, I'm very pleased with the rusults to date and I feel the move from the OEM Group 24s was a good one. Wish the switch wouldn't have been left on but that's life.