Battery capacity tester for 12v SLA in backup power supply?

[Dave_H]

the deeper the cycle the fewer the battery will give. btw at the rate a ups drains its battery when it hits 10.5v shutdown the battery may only be 50% drained. and you get less as it ages.

Regular SLA "gel-cell" battery will be around 12.0v at 50% capacity, under light load. Dave