The first 100,000 kilowatt hours of backup power pumped out of the battery bank while living off grid passed several days ago, and so did the first modest deep cycle battery bank used in the system.
Six batteries. Each 6-volts with 400 amp hour rating. Paired in series and those three series-wired pairs wired in parallel and then exercised nightly as well as during prolonged overcast and stormy days for fourteen years. Each battery weighing in at one hundred seventeen pounds wet, they cost about $1500 brand new fourteen years ago. A bargain.
These days, a comparable new set runs twice that amount, but $1500 of 2004 dollars divided by 100,000 kwh comes out to cost of about 0.015 dollars per kwh or $107 per year for just over 714 kilowatt hours of backup electrical storage needs each year. The first two of those years were spent preparing the system to power not only daily home electricity needs but enough extra electricity for a creative works studio and business as well.
The business part has gone away. It's all personal projects work from here on out, for which I am perfectly eager to spend twice the amount for a new battery bank today.