If you have a real load tester, one with a carbon pile variable resistor, you can take a voltage reading during a hot start attempt, and then use the carbon pile to drop the voltage to the same level and see how many amps of load it takes to create the same terminal voltage. For instance- - - -hot start voltage of 9.5 volts might convert to a 400 amp current load. That would be an excessive current draw for a good-condition starter, indicating excessive drag inside the engine.
Most "battery testers" have a constant 100 amp load built in, which is virtually worthless for any serious check of a battery's cranking capacity. They're sales gimmicks to make an already-weak battery seem really bad and sell a new battery. I have a Snap-On digital battery load tester with a very heavy duty variable load cell which can be used for accurate evaluation of a battery, but it's also about $2500.00 worth of professional-quality equipment. Checking specific gravity and cold cranking amps after a 15-second load test is the only effective way of evaluating a battery's capabilities, but very few shops and virtually no retail battery vendors even know how to do that type of testing.
Jerry
