This is a comment to all and relates to Bruce's concerns.

Our batteries are our lifeblood and because of that we need to treat them with respect. At the very least all owners should go to various sites such as these:

http://www.lifelinebatteries.com/rvbatteries.php

http://www.windsun.com/Batteries/Bat...ting%20battery

The important thing is to understand batteries, how to charge them, and what impacts their life.

The next step obviously is to get to know your coach. How is your inverter set up for charging? What is the charging voltage of your alternator? Do your batteries hold a charge or are they losing a charge? If they are losing a charge why are they losing a charge? Putting on a charger to compensate for batteries going dead is akin to taking an aspirin for a brain tumor. It masks the underlying problem.

To address Bruce's question specifically, there is a simple way to determin if you have a bad battery. Separate the batteries electrically (take the cables off them) and using a battery tester check them to see if they are just in need of a charge or if they have gone bad. In the absense of a tester, there is another way, but it will be inconvenient if you are living in the coach. Separate the batteries electrically. Measure and record the battery voltage for each battery. Do not reconnect the batteries or use power from them, but let them sit overnight. Remeasure the voltage after a 12 or 24 hour period. If you have not pulled any power from them they should have retained the voltage measured the day before. A bad battery will show a much lower voltage.

In the case of chassis batteries this should be no problem, but if your house batteries need to be checked you really can't use the second method if you are using the coach.

I will maintain my original position on this. If the chassis batteries are losing a charge within days or even a couple of weeks there is something pulling them down. As Tom points out it could be a bad battery or there is a load on them that needs to be determined. There should be no loads with the switches turned off except possibly some DDEC circuits. Those circuits should have minimal current draw, if any.