battery has voltage but inadequate amperage?

Is it possible for a car battery to have adequate voltage (head lights comes on etc, but car won't start). The other day I wasn't able to start my car (You can hear a click but starter won't turn over). So I
towed it to the mechanic and left it there. He said my battery is no good and replaced the battery for me. Anyway he explained that it had voltage but failed the load test. What is involved in the load test? Is it something you can do on my own in the future? What kind of equipment do I need? I have a autoranging digital multimeter if that will help.
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Sam Kaan wrote:

Yes. YOur battery could have the right voltage but lack amps. Voltage is a function of the Pb to PbS to Pb chemical reaction. Amps are a function of plate area. A load test involves putting a known load on the battery and watching the voltage and/or amperage draw-down vs. time. You can do it yourself but you will have to get a battery load testing device. They are not cheap.
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When performing a load test, the tester simulates a starter draw on the battery.
Sounds like you have considered building a load tester.
One needs to understand you get what you pay for based upon price. The cheap nichrome wire resistance can be bought as inexpensive as $15 on internet tool web sites up to $60 at NAPA. Carbon Pile testers are cost prohibitive unless used in a fleet. There is a Motorola tester available that combines the best of many worlds. Please search the Internet.
A load tester consists of a resistance as cheap as nichrome wire to expensive as carbon pile discs used as a rheostat. Besides impressing your neighbors. A home made load tester can be constructed using sealed beam headlight bulbs. Using ohms law one can wire the bulbs series and parallel to have an average 5 to 10 seconds desired resistance.
Average resistance encompasses knowing starter draws for a wide range of starters i.e. 150 amp draw for 4 cyl aluminum rice rocket engines up to 250 amp draw for older American cast iron block engines with big starter motors.
Has anyone checked the starter for amperage draw? Has anyone checked the battery cabling for any loose connections. A bad starter that has a flat spot can cause a misdiagnosis of a battery.

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Yes, a battery can lack amps. Grounds play a big role in got voltage, not amperage, situations. Corroded grounds will increase in resistance, show ok with test light, but will not carry the * current * needed to start a car. Beef up grounds and enjoy longer battery / alternator life.
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