A turlough is a unique type of seasonal lake found in Irish karst areas which are formed through the annual welling-up of water from the underground water system. Water supplies from wells in karst topography may be unsafe, as the water may have run unimpeded from a sinkhole in a cattle pasture, through a cave and to the well, bypassing the normal filtering that occurs in a porous aquifer.
A battery rated at 180 amp-hours over 6 hours might be rated at 220 AH at the 20-hour rate, and 260 AH at the 48-hour rate. Much of this loss of efficiency is due to higher internal resistance at higher amperage rates-internal resistance is not a constant-kind of like the more you push, the more it pushes back.
Amp-hour capacity: Available amp-hours, at a fixed rate, over a given period of time (e.g. 20 hr rate, 5 hr rate., etc). Most true deep cycle batteries are at the 20 hour rate. A group 27 battery has about 100 amp hours (5 amps for 20 hours at 80 degrees F). The problem is no one uses exactly 5 amps. If you're pulling 10 amps, you may have a 70 amp hour battery; if you only draw 2, you may have a 140 amp hour battery.