90% of these problems you could solve on your own, go buy a voltmeter like I said earlier and Shawn echoed. Its very simple.
Load testing is a very usefull way of testing the cold cranking amps that the battery can put out. But, the only way of test the battery to the fullest, i.e. every individual cell, is with a hydrometer, no if,ands, or buts. Matter of fact, you can have a battery with a "dead" cell and still
test good on a load tester. I've seen it a hundred times. Thats why the "professionals" hydrometer check batteries first, then complete a 12-24 hr charge, allow it to stabilize, and then load test it for cold cranking amps.
Does the quality of batteries make a difference? Of coarse, plate design makes a huge difference. And the quality of the paste used on the plate, determmines how effectively it can complete the chemical reaction that produces voltage. Exide, the same battery that Junked is using, is among the worst batteries on the market. Its a huge company, that spends millions on marketing, but their batteries hardly every put out the cold cranking amps advertised. Remeber that when you buy batteries they can advertise cold cranking amps, cranking amps, and hot cranking amps. These different ratings make a huge difference in power output. Sorry, i'll get out my soapbox now.
Jeremy