battery load test

[ram_man]

well I decided to load test all 3 vehicle. the dodge failed. but the other two did alright I suppose.
the Saturn read 10.0v and 400cca
the Honda read 10.2 410cca
the Saturns battery is rated at 625cca so that's kind of low. the Hondas is rated at 450 so its ok. the temperature was 40 degrees when I tested them. any idea why the cca is what it is?

the dodge has 11.8v so I charged it. and after charging it, and it load tested weak but not
bad and then I thought well Ill se how the charging system is and went to start it and nothing happened. so then I hooked the tester to it and it went from 12.5 to zero when loaded. I guess the load test killed it. it was on its way out though.

 

[caravanmike]

According to my calculations the saturn battery is 64 percent of what it should be! That was an "F" in my high school

How old was the ram and saturn batteries?

 

[ram_man]

Originally Posted By: caravanmike
According to my calculations the saturn battery is 64 percent of what it should be! That was an "F" in my high school

How old was the ram and saturn batteries?


saturms is 9 months
dodge is 2 years

 

[JHZR2]

When I've read how to do load tests, it was to load to half the cca and watch the voltage drop. Sounds like you did something else. What kind of tester?

 

[ram_man]

Originally Posted By: JHZR2
When I've read how to do load tests, it was to load to half the cca and watch the voltage drop. Sounds like you did something else. What kind of tester?


it is just a analog super start load tester.
for some reason we learned that in class but when we did it using the snap on load tester the big roll around kind we didn't have to go to half of cca its smart enough that it knows I suppose. it asked the voltage so my guess is it does the math for you.
my cheap little analog tester has one button that's it.

 

[Donald]

What exactly did you use to do the test?

A carbon pile load tester set to 1/2 the rated CCA? Run 15 seconds, when it beeps, quickly read the voltage on a temp compensated scale. Battery needs to be fully charged.

A conductive tester will tell CCA, but the test will not pull the voltage down.

 

[Donald]

The cheap load testers are just 100 amp loads. OK, but not all that telling of the true condition.

No tester can determine the labeled CCA of the battery in order to test it. You need to enter it.

 

[ram_man]

Originally Posted By: Donald
The cheap load testers are just 100 amp loads. OK, but not all that telling of the true condition.

No tester can determine the labeled CCA of the battery in order to test it. You need to enter it.


yea it goes from 300 up. how are they considered accurate if they aren't that accurate?

 

[ram_man]

it does 135amps. I don't fully understand the cca on it though.

 

[SHOZ]

Isn't CCA a measurement at 0F?

CCA is critical for good cranking ability. It's the number of amps a battery can support for 30 seconds at a temperature of 0 degrees F until the battery voltage drops to unusable levels. A 12V battery with a rating of 600 CCA means the battery will provide 600 amps for 30 seconds at 0 degrees before the voltage falls to 7.20 V (six cells). ]


http://www.autobatteries.com/basics/selecting.asp

 

[ram_man]

Originally Posted By: SHOZ
Isn't CCA a measurement at 0F?

CCA is critical for good cranking ability. It's the number of amps a battery can support for 30 seconds at a temperature of 0 degrees F until the battery voltage drops to unusable levels. A 12V battery with a rating of 600 CCA means the battery will provide 600 amps for 30 seconds at 0 degrees before the voltage falls to 7.20 V (six cells). ]


http://www.autobatteries.com/basics/selecting.asp


Right. I meant I don't really understand the dial on the load tester it's kind of weird.

 

[SHOZ]

Unless the battery temperature is 0F then it is all just calculated extrapolation. Not exactly accurate. Kind of out of date too as most cars will have the engine control relays drop out at 10.5V anymore.

 

[Donald]

I would think most people cannot use a load tester to test CCA. You would need the battery at the proper temp (0F) and a load tester that can deliver the load for longer than 15 seconds. The normal carbon pile testers people have should be used for only 15 seconds then they need to rest and cool down for a few minutes.

If one wants to measure CCA, then a Midtronics conductance tester (or similar) is needed.

 

[ram_man]

Originally Posted By: Donald
I would think most people cannot use a load tester to test CCA. You would need the battery at the proper temp (0F) and a load tester that can deliver the load for longer than 15 seconds. The normal carbon pile testers people have should be used for only 15 seconds then they need to rest and cool down for a few minutes.

If one wants to measure CCA, then a Midtronics conductance tester (or similar) is needed.


Why do they even put a cca scale on it then?

 

[SHOZ]

CCA is a marketing scam. How big of wire do you need to carry 600A with low resistance through the wire?

 

[Donald]

I do not think CCA is a scam. But you need something more than a garage or individual has. Consumer Reports measures CCA via load, but I am sure they have a freezer and some expensive testing equipment.