Exploring the red-light district
Wait! come back! I can explain... I'm not talking about that red light! I mean this one, the red light on our charge-controller of course! The photo is a messed up one that I took when the flash was really needed, but it suits the post quite well :-) The red light means that the battery is very low and that the power will be cut off soon.
In the last few months we've noticed that the performance of the battery has decreased a lot, and we're getting into red-light territory more and more often. Then a few days ago, we had a full charge at the end of the day (flashing green light), and then after only an hour or so on the net in the evening, we were right back in the red light zone!
So we thought we really needed to explore this red light territory thoroughly! And that's when we discovered what I was trying to say above - that all the potential is there! It took an hour to go from fully charged (about 13.9 volts) to the red light at 12.1 volts, but over an hour to go from there down to 11.95! And we still don't know how far the red-light zone goes - we went all the way to 11.75 volts today, but we still haven't been cut off!
So we're going to be spending a lot more time in red-light territory from now on, and I'll even be doing a lot of my work down there, because we really need to know once and for all how far down it goes :-)