Dead Batteries = $10K (and a lot of work)
The heart of a decent Solar PV system is the batteries. You need a way to store the electricity produced by the Solar Arrays or backup generator. Replacing improperly maintained batteries can get expensive.
The homestead was only 5 years old when we purchased it from the original owner. Although they had put in a top of the line solar PV system, the battery configuration was less than optimal. The 24 large batteries were stacked in a cabinet on three shelves with 8 batteries each. The top row was almost 8 feet off the floor making maintenance very difficult.
If properly maintained, good quality batteries should last for approximately 10 years or more. In our case, it turns out the top bank was pretty well fried with the bottom bank not far behind. We had a couple of critical shut-downs due to the batteries not taking or holding a good charge.
We knew replacing the batteries would be expensive, but also knew it would never get cheaper. We had to bite the bullet. With 24 new batteries at $325 each and a slew of new heavy gauge cables and installation - we were looking at $10K.
When consulting with the solar tech we decided to get rid of the 3 shelf cabinet and build a new one to put all the batteries in two rows on the ground - a single bank of 24 two-volt batteries - much easier to maintain! I'm glad the solar tech brought help the day of install because the batteries clocked in at over 100 pounds each.
Fortunately, the system is setup as such that we could completely bypass the batteries and run the house on the backup generator for the day it took to replace everything.
So far, so good. The old batteries required 5-7 gallons of distilled water every month. The new ones are only taking about 1 gallon every three months.