peasodos

iTrader: (1)

Well reviewed on amazon for testing car batteries:

Also highly recommended by this mechanic on youtube with over 1.2 million subscribers:

If it shows weak on this load tester your battery is not good.

• Tests 6 and 12 Volt batteries up to 1000 CCA, ideal for cars, light trucks, RVs, motorcycles, ATVs, boats and lawn tractor batteries
• 100 Amp load test for 12 Volt batteries; 50 Amp load test for 6 Volt batteries
• Tests load, battery condition, starter motor draw, with complete charging system diagnosis

bclexus

You will never see a battery shop or battery specialist use such a device. He will have a beefy load tester that has the ability to draw half the battery's CCA for 15 seconds multiple times if necessary. In fact, the recommended way to test a vehicle battery is to 'apply a load equal to one-half of the CCA rating of the battery for 15 seconds'. A 100 Amp load tester is simply not going to be able to properly test 99.9% of car batteries. It's like testing a couple of Size C cell batteries by turning on a flashlight for 3 seconds and seeing the bulb light up. That's not much of a load test!

bclexus

Your battery tester is practically worthless to be honest about it...but don't believe just me - the experts say that too. It only provides a low amperage resistance load known as a 'toaster' type load because the load is merely a heating element (like in a toaster), in lieu of a carbon pile load which is in quality battery load testers.

Load testing with a variable carbon pile load provides a greater degree of functional certainty. In this test, a load equal to half the CCA rating is applied to the already fully charged battery for 15 seconds while the voltage across the two terminals is measured with a DMM. The general standard is that the battery passes the test if the voltage reading stays above 9.6 volts throughout the entire test. Unfortunately, the test does not give reliable results when the battery is cold, especially if its internal electrolyte temperature is near or below freezing. The test cannot be used to condemn a battery that is not at least 75% charged. And, since the test in essence spills out a good deal of the battery’s energy, the battery must be recharged before it can be returned to service. (As to the “toaster” type load testers that draw a fixed current of 100 or even 200 amps, they have no place in a professional garage.)

Reference: https://www.motor.com/magazine-summa...tery-of-tests/

You Tube

You Tube

eddie420

You're digging too deep into this for the sake of digging. "...a greater degree of functional certainty". The inexpensive load testers out in the market are relatively accurate. Who cares what's in a professional garage? Just because I don't have Snap-On tools doesn't mean my HF or Craftsman are worthless.

bclexus

A little 'toaster' battery tester simply cannot determine whether a vehicle's battery is good, or not. The reason why is because it is incapable of pulling a load equal to half the battery's CCA rating for 15 seconds, which is the accepted professional way to determine whether a battery is good, and will be dependable in the near future.

To compare it to your tools scenario - you may have a torque wrench capable of measuring 40 lb-ft of torque. That's great, but if you need to measure 100 lb-ft that particular tool is incapable of measuring the torque you need to apply. It doesn't mean that your torque wrench is inferior or bad, but it sure is worthless to measure what you need! Right? The same would apply to having a 2019 LS 500 instead of a dump truck when you need to haul 5 tons of rock. That LS 500 may be a great car to haul family or clients around in, but it really is completely and totally worthless for your need to haul those rocks!

Watch the two videos in Post# 18. Those two videos are totally unrelated, yet they both explain the exact same procedure to properly load test a vehicle battery....something a little 'toaster' battery tester simply cannot do. And that's a fact!