Electrics Problem

Sun 2 Dec 2007 10:35
We have an electrics problem that we could do with some help to resolve/ understand.
The boat has 24v house batteries and a mastervolt Mass 24/50 battery management system. Yesterday evening the Voltage in the batteries registered 14V and the autopilot and other equipment started to pack up. We ran the engine to charge the batteries back up to 100% and over 25V. Since 3am to 9am the voltage has dropped down to 22.27v. Our consumption of power ranges from 2.7amps to 7amps which we believe is normal for the equipment we have on.
We can charge the batteries with the engine and will probably have to run it 3 times a day. What we do not know is how low a voltage we can allow to the batteries to fall to without increasing our problems. Should we charge when the Voltage has fallen to 22v or can we go down to 20V? Do we need to maintain the batteries at 24v+ or can we get away with less.
Yesterday pm we changed a temperature sensor on the batteries as the previous one was not stuck to the batteries but just sitting on them. However we do not see how this would affect the voltage.
The other possible cause of the problem is we had a wind generator installed just before we left Las Palmas. If this has not been installed properly could this be the issue.
We do have a multimeter on board but need some advice on where to look for the problem.
Any thoughts on what is causing our problem would be appreciated.