We
record our readings and battery
maintenance in a
Maintenance logbook.
Here you can spot any trend shifts. The "bathtub-curve" of early failure is important to
monitor so you can find a bad cell before your warranty runs out.
We check water every month, and
record per cell any variance.
We check Sg, temperature, and per battery voltage and record every reading.
We re-tighten every terminal 3 monthly.
We wipe down the surface with an Alkaline water rinse 3 monthly.
Our house bank is 12 T105's. I refitted a
Catamaran recently and put in 20 T105s with a central watering system.
You must spot a change before that bad cell has the effect of raising the resistance in its bank, and that will make you cook the other ones dry.