This shows the battery bank voltages over the course of Sunday. During the morning, the only things running were the pc and, periodically, the fridge.
The afternoon was a little busier, with the paint mixer and lights on at various points. There was also a little wind about, which helped maintain the battery voltage. The really deep dip you see is because of the water pump, which only runs occasionally to top up the water pressure (must have been teatime then).
A little disappointingly, this is very similar to the chart I posted in September 2008. I had this chart in mind as a comparison, which is why I ran the generator at 10.00!
Looking at the two charts, I'd say that there has been no significant improvement in the batteries performance in the last year.
I had previously been running the generator whenever practical, to give the de-sulphination unit as much chance as possible to work. After seeing these charts, I think I'll change tack and only run the generator for an hour or so to recharge the batteries when the voltage drops below say 24.4 volts. My system is, after all, setup to work like this.
The 24.4 volts is a little arbitrary, but should leave more than enough charge to last through a cold evening with the heating running, without needing to run the generator at an unsociable time.
Ideally, I should not have to run the generator at all. Any power I use should be restored over time by the wind generator or, possibly, solar power.