Testing battery capacity with an electronic load

[WSJ]

My batteries (US 8VGC XC2 - 8 Volt) are 4 years old and the voltage was going down to 1.722 Volts per cell with a 50 A load, after only 20 AH had been used.
I designed a battery capacity test system using a Link-10 (E-METER) to measure AH. The low voltage alarm in the Link-10 is used to open a solenoid to disconnect the constant current load (Power Mate Lectra Load II, 300 A solid state load) at the programmed voltage. I selected 2 batteries to test based on the unloaded terminal voltage a few hours after charging. The load current was 60 A. The Scope Meter was used to plot battery voltage.
The lowest voltage was 8.020 with a capacity of 18.5 AH at 76° F and highest was 8.120 with a capacity of 56.7 AH at 79° F.

[scottyb]

How long did the test last at 60a ?

[WSJ]

Originally Posted by scottyb

How long did the test last at 60a ?

At 60A; 1AH = 1 MIN. Total time for the second battery 56.7 min.

[WSJ]

What other ways are used to test battery capacity ?

[scottyb]

I use a Lestronic battery load tester. Which uses a set load similar to 60a you use and monitirs pack starting voltage and end voltage using a preset low voltage cutoff ... It gives the results in minutes. where a healthy pack would run 110 minutes. THis allows a shop to give the customer a difinitive answer to how are my batteries..... the answer may be they tested at 85% capacity.