such as the Associated model 6029 (the operating instructions don’t seem to explain this). The green area gets wider and the yellow area narrower as you go down closer to the rotating point of the readout needle.

The yellow stepped area is an indicator of Cold Cranking Amps that your battery has in reserve when doing the ten second load test. Check the CCA rating of your battery before the test and then see how close the reading matches your battery rating when you have the battery under a load. This will give you a rough indication of the condition of your battery.