The evening of the day Nome and Steve came, Kantara suddenly suffered a massive drop in her battery output' Lights went very dim, the fridge turned off, and the water pump couldn't switch itself off. I rushed to the electrics cupboard, and switched on the mains-powered battery charger, and all was well. But the battery monitor was showing only eight volts just before I did that, and this had looked pretty serious to me.
The boat has two domestic electrical systems. There is a 12 volt system powered by three big lead acid batteries which are trickle-charged by four sizeable solar panels. This system powers most of the lighting, the CD player, TV, fridge, central heating pumps, shower pump and water pump. And there is a 240 volt system for five lights, the microwave oven and grill, the washing machine, a battery charger, and a number of 13 amp sockets for computers, vacuum cleaner, bread-making machine and the like. In the marina, we have a shoreline which plugs into a mains outlet just by our mooring, and supplies mains electricity to us. Whilst cruising, the 240 volt devices are powered by an engine-driven generator (which has just broken down) or an inverter, which uses DC energy from the batteries and converts it to AC. If our batteries fail on the cut, we are without electricity altogether. We can still cruise, though, since the starter motor is powered by a totally independent battery.
Since the evening when the batteries slumped like that, I have been rather paranoid about them. They are brand new, having been put in the boat just a few days before we sailed her away from the marina at which we bought her. To cut a long story short, the various battery management and monitoring systems were giving me contradictory information about the state of charge of the batteries, and I was both confused and concerned. Enter Simon, who had done some minor jobs on the boat before we bought her. He came along today and checked the lot for us, answered my many questions, and put my mind at rest. The batteries are not damaged. I now understand the monitoring units, and can happily manage the power while we are cruising. I have literally lost sleep over this, being very angry at my own ignorance, and concerned about the possible consequences of that ignorance. Once again, I have learned something new about the boat, and am much better for it.
And the weather today - wonderful! Blue, cloudless sky, warm and still. It was a shame, yet again, that we could not get out on the canal, but it was fantastic just to be out in weather like that.