I bought the Schumacher BT-100 battery tester earlier this year. I used it recently to test a 6 year old Motorcraft battery. The CCA on the label stated 590CCA. I measured 800CCA. I did the test a couple of times to make sure that I was reading it correctly. Is this normal?
you didnt test for CCA. because it wasnt 0f out(and the battery 0f)
and yes its makes a large difference.
Cranking amps are the numbers of amperes a lead-acid battery at 32 degrees F (0 degrees C) can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12 volt battery).
In other words, CA/cranking amps determine how much power you have to start your car in most climates. The basic job of a battery is to start an engine; it must crank, or rotate the crankshaft while at the same time maintain sufficient voltage to activate the ignition system until the engine fires and maintains rotation. This requirement involves a high discharge rate in amperes for a short period of time.
Since it is more difficult for a battery to deliver power when it is cold, and since the engine requires more power to turn over when it is cold, the Cold Cranking rating is defined as: The number of amperes a lead-acid battery at 0 degrees F (-17.8 degrees C) can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12-volt battery).
In other words, CCA/cold cranking amps determine how much power you have to start your car on cold winter mornings.
You were right. I read the directions and they are now clear. WOW what a difference!
Thank you everyone for your inputs. It was user error. What kind of battery testers are available to actually measure CCA? Before this tester, I used a regular DVM and measured voltages before and during starts. I'm used to testing telecom batteries, where we measure voltages before and after discharge, intercell resistances, and electrolyte levels.