Load testing batteries is something I got very used to doing up here when winter hit when I was a tire man at a Chevron Station. Load testing is as follows:

Battery is hooked up to a machine that has an adjustable amperage load dial. The battery is loaded to 1/2 of its cold cranking amps, if the battery cannot hold above a certain voltage after 15 seconds (11 Volts IIRC) the battery is "toast" or unsuitable for use as a starting battery.

I keep my old batteries around for testing out 12 volt components as well. A battery that fails a load test will usually still hold a charge, you just cannot put much demand on it. (like a starter)

-S/6

1/2 CCA for 15 seconds @ 11v? Whoa, severe test. My optima droped to 10v with a 100a load after like 1 second but it held 10v. I know someone elses that I load tested and it did the same thing. His is probaly 1 or 2 years old but is in seemingly good condition and serving him fine. It is one of the smaller redtops that costco has, not the bigger Model 800U.

Anyhow, my next optima will probably be a yellow top regardless. You sacrafice some capacity but gain the cycling ability. Not like you ever use its full capacity anyhow.

Curious, do you remember the brand or model of the battery testing machine you referd to?

The tester was a NAPA brand, no idea on the model number. The voltage requirement during the test may be lower, it has been so long since I physically did one I can not remember (8 volts would probably make the most sense). But you are right, it is a brutal test. Many of the cheap convenience store batteries will not pass the test 'new', depending on how long they have been sitting on the shelf.

-S/6