Battery Load Tester Question

[JD5210]

I borrowed an actron cp7612 battery load tester from a friend to help another friend test 3 12 volt batteries.

One of the batteries, which has been off the battery charger since last night read 13 volts with my volt meter. When I connected the load tester to it and flipped the test switch after just a few seconds the load test got hot and while the switch was on the needle on the meter just moved a little to the left.

The other 2 batteries with the load tester switch flipped on for 9 seconds it never got hot and while the switch was on the needle went all the way to the left.

I do not feel the tester is the problem, but that the battery is.

Any suggestions as to what is happening in the battery that would cause the tester to get hot after a few seconds? We plan to take the battery into town to Autozone next week and see what they saw as well.

Thanks in advance for any help.

 

[jonsstihl]

I think what you are seeing is normal. Usually the testers use a heating element to load the battery. the battery that got the tester hot is good and the other two are dead since they didn't have enough energy to heat up the coil.

I don't have an actron tester but mine works the same way. the important thing to watch for is the voltage drop when the load is applied. the needle moving all the way to the left indicates that the battery can not keep the volts up while a load is applied. the less the needle moves the better the battery

 

[k0ua]

Load testers should get hot real quick when putting a load on a good battery able to deliver large amounts of current to the tester. Load testers will remain nice and cool when testing "dead" batteries. The voltage scale should move a small amount to the left, indicating a small voltage drop at applied load. The load tester is nothing more than a resistive heating element, darn near a dead short (very low resistance to the battery), and a volt meter.

The concept of operation is to throw a very large current load on the battery for a small period of time, usually no more than 10 seconds, see if that battery can sustain that load and maintain a reasonable voltage while doing so. Of course with a large current at a near normal voltage level for that battery equals a huge amount of power being drawn from the battery and dissipated in the form of heat from the resistive heating coil in the tester. Make sense?

 

[JD5210]

Thanks. I understand what was shared and now have the correct understanding how it works.

Thanks again.

 

[DFB]

I say the testing was successful

 

[k0ua]

This is not a bad instrument to have around for testing batteries. It can tell you much more about a batteries ability to deliver current into a load than just a simple voltmeter test. It is also easy to understand for persons that may not have the whole Ohms law thing figured out with its "good" "bad" sections on the meter. I would like to have one myself.

Amazon.com: Actron CP7612 Battery Load Tester: Automotive

 

[CobyRupert]

There also handy for checking the charging system and the starter.

 

[DFB]

I had been looking to get a battery load tester recently after watching a video on the newer digital conductance type testers.

https://www.youtube.com/watch?v=VjeXCF0SUT8


Even had even a decently priced one with good reviews in my cart on Amazon too

Amazon.com: SOLAR BA9 40-1200 CCA Digital Battery and System Tester: Automotive

I was kind of torn between paying the price difference between old tech and new, even though searching tool catalogs and online the old carbon pile load testers seem to run all over the board in price, almost as much as some digital units.

Coincidently we were having an ongoing starting issue for the past several weeks with the old JD 2855N at work. It has dual batteries...

And long story short the TSC store here has them stocked up right now and for less than $20 too, so I bought one there other day.

Turned out one battery was bad.




Traveller Battery Load Tester/Voltmeter - For Life Out Here

Should meet my needs for the time being (provided it doesn't fry out ) being that all my batteries are wet cell types except for one at the moment.


I still may shell out for for digital unit seeing they can test the CA on other types of batteries like those in a jump starter.

Some say they are more accurate...they definitely are more versatile if your needs run beyond testing wet cell type batteries only

Earlier this summer I purchased an new battery for my riding mower based on an auto parts store worker's recommendation after he had load tested with a hand held carbon pile tester the battery I brought in because I was having some perplexing starting issues with my 15 year old yardman lawn tractor. Even with a new battery the problem remained (turned out to be the starter which I eventually replaced )

I even see a CEN TECH unit out there for the diehard HF fans


https://www.youtube.com/watch?v=XtWflJTp_mM

 

[k0ua]

Keep in mind these modern conductance digital battery testers work on a whole different principal than a simple battery load tester. These conductance digital battery testers pass an AC waveform thru the battery to measure its internal resistance and calculate what current it could theoretically provide.
The simple load tester puts a big load on the battery and by watching the meter you see how it handles that. Of course these type of load testers actually drain the battery for a short period to simulate an actual starter load. There are probably Plus's and Minus's to each design. How about that... a battery related pun!:laughing:

 

[RickB]

There also handy for checking the charging system and the starter.

And when connected different ways with a little thought, a cheap 100 amp carbon pile load tester is a great tool for testing battery cables and ground connections that may be hard to access.