Carbon pile Battery Tester

Ted in NE-OH

Well-known Member
Harbor Freight has a 500 amp carbon pile battery tester, anyone have one and tried it on a 6 volt battery? Did it work>
 
Yep, they are a good unit for little money ($50). Put a drop of heavy oil behind the pile control knob to lube the screw & nut don't overheat the pile by leaving a load on for more than a few seconds, it will do a good job for many years. Has big easy to read analog volt and ammeters.
 
It works fine on 6V although they say 12V. Only the red / green bands indicating good / bad at 12V will not be accurate on 6V , but you can understand voltmeter readings without relying on them.
HF load tester.
 
Watch your magazines and news papers. I get a number of HF coupon ads and each one has a coupon for 20% off an item of your choice.
 
Hello Jon Hagen,


It takes more then a few seconds to properly load test a battery. Hopefully it will take the load long enough to do the test. Its price sounds real cheap.? I question its quality-longevity. A VAT40 is what I have used for years with no problems. Cost more the $50 though,


Guido.
 
Hello Ted in NE OH,

For the occasional user I guess it may work? For $50 it sounds cheap? Anyway it will work on 6 volt systems. Load test your battery at 1/2 the CCA ratings. Hold the load FOR 15 seconds. A passing battery voltage should be 9.6 V OR GREATER @ 80*F for 12 V batteries. For 6 V Batteries should be 4.8V OR GREATER, again @80*F and loaded @ 1/2 its rated CCA capacity for 15 seconds,


GUIDO.
 
I have one and no reason it wouldn't work on a 6v. You just crank the voltage to the desired value with the pile loose. Start turning the pile knob cw and watch the amperage increase....have to turn it maybe 10 turns before you start seeing conduction....depends on how far you backed it off after the last test, or whomever backed it off last.

I test 12v batteries at 150 to 200 amps depending on size and what it starts. I require my terminal voltage (on the meter) to hold at least 11v during those current excursions which should only last long enough for you to get your reading......things get hot fast.

On a 6v since work is VA and V is ? then A has to double. V proportionally should hold 5.5 v under load.

If the battery can't hold the voltage you have an internal resistor in the battery (effectively in series with the load current the battery is producing) that is dropping too much voltage due to too high a resistance value. This is usually caused by sulphate scale that insulates the plates from completing their chemical change efficiently and producing adequate current.

Always start with a fully charged battery to get accurate results.
 
Hello Texasmark1


Battery capacity determines the load test, not 150 nor 200 amps, and 11 volts? Like I posted many times before, including my answer to Ted. HERE IT GOES : A battery under test is loaded @ 1/2 its rated CCA for 15 seconds A good 12V battery will show at least 9.6 volts or greater @80*F. 6 volts voltage should be 1/2 of 9.6 volts with the same test as the 12 volt battery, Again LOADED @ 1/2 the CCA and holding the load for 15 seconds. If the tester can't do this kind of test, then batery capacity is a big ? And certainly not valid

GUIDO.
 
I have that HF tester for about 5 years now, it's a surprisingly good unit for the price and will fully load a 1000 CCA battery for that 15 second test, as I have done it many times.
That many watts generates a lot of heat though, so I would not feel safe repeating that test until the unit has had at least 10-15 minutes cool down time.
 
Hello Jon Hagen,


That is the right way, cooling the tool between tests. That will keep tbe smoke in HA HA.Like I said you need to properly load a battery to perform a valid test. I am gkade that its working for you,

Guido.
 
Thanks for reinforcing the way I was taught to do it....
I had a service manager that would load test batteries that a customer would bring in during the dead of winter and load test them after the customer had been trying to start something for half the day. Funny how many would fail!
I would add to testing batteries the use of good hydrometer as well to check for weak/poor cells.
 
Hello Tech7,

It's always good to see the light bulb go on. I just keep repeating the same simple test procedure. Some people just don't get it. Any text book will have the test. Hydrometer is not a real good test of battery capacity. One broken connector between cells is all it takes for a battery to fail good hydrometer readings or not. A volt meter is a better way to asses battery potential. Capacity is verifyed with a load test.................. period!

Guido.
 
Hello John *.?-!.*

The way I see it makes no difference. If the 12 settings will draw 500 amps which is 6000 watts, then at 6 volt setting should be able to draw 1000 watts again 6000 watts.


Guido.
 
Well I guess I just do it by the seat of the pants rather than the book. But it does sort out the bad ones. Guido: If it had to do with a battery I figured you'd jump in, and you did. Grin

I ain't testing CCA. I want to know what voltage is on my battery when I hit the starter. Different question, looking for a different answer. Down here we don't have winter time battery problems like in the cold climates.
 
That works by using a container of carbon for a resistive load that is compressed by turning the knob higher to get the current you want. A 6 volt battery will only deliver half as much current for a specific resistance value as a 12 volt battery. To push 500 amps through it at 12 volts would mean that at the highest setting, the resister would be .024 ohms, for 6000 watts If your supply voltage is only 6 volts into a .024 resistance, the current will only be 250 amps, for 1500 watts
 
Amps are determined by the size of the cell along with the # of plates. Each cell produces 2 volts in a 6 or 12 volt battery. Amps are often less in a 12 volt because the cells are smaller than a 6.
 

Tex your way works it will at the least pass a bat that's down on its ability to store long term storage but still will get it started if all your ducks are in a row.. Just remember the days on the bat are numbered...

I pass them all the time just the way you do it but tell the customer any signs of slow crank'N REPLACE the bat,,, Some fail quickly some last for years...

What a true load test tells you is the bat is close to are 100% efficient... What your test tell you if you do not do a true load test is the bat may be short winded... It can not supply the amps to get'er done with a normal no start issue..

Its a fine line you walk its a call...
 
Helo Texasmark1,


Hot climate is actually worse case scenario for battery longevity. Heat expands the separating plates making a short a qwicker affair. Arizona type climate comes to mind. Two years on a battety is about all you get out there. Anywho test is the same. Test amp draw on a cold and hot engine. You will see what I mean,😂😂

Guido
 
Hello Texasmark1,

You are probably testing at 1/3 capacity?. If it fails at that rate you sure got a bad one. Really load testing just verfies storage capacity not output power. That is for another thread though,

Guido.
 
I agree with your testing procedure Guido. . We were always told 9.7 on 12 volt batteries, half cold crank and 80 degree, but that is nit picking. Taking temperature into consideration gets a little more complicated.

Back in the OLD days, mid 50's to early 60's, we were testing at half of ampere hour ratings on 6 volt and 3 time ampere hour ratings on 12 volts. Don't even see ampere hour rating now days. Some confuse ampere hour rating with the amp ratings they show on modern batteries.

I have the Allen carbon pile tester I broke in on in 1958 at the dealer. The new outfit threw it out. Too complicated for young tech's I guess. I am going to use it this afternoon on a pair of batteries in a Magnum,(don't ask me the model as I don't keep up with anything newer than when I left CaseIH in 95.

By the way, I never was a Tech, I was a MECHANIC. Techs work in hospitals checking urine samples etc.
 
Yes, amps are amps I have two of the HF carbon-piles and they work just as well as my old AC Delco tester that I got 40 years ago that cost four times as much. These HF testers are pretty good quality.
 
Thanks folks for a good discussion. I have 10 tractors with mostly 6 volt batteries. Just because a battery doesn't turn over a tractor doesn't necessarily mean the battery is bad as there are many other possible. Starters are hard to test under a "standard" load. With 10 tractors I want to test all batteries once a year and replace the weak ones.
 
Hello pete 23,


Three times Ah rating is correct, 12 volt voltage is 9.6V. Check hobo's posts. One has a picture of the meter happily pointing 9.6 and 4.8 volts like I posted. Some wifes tales are hard to live down! Some people are not good training candidates, if you know what I mean. You are wrong about Techs though, I went to get new tires and guess who put them on? Tire Tech. HA HA. I am old school also. Chrysler- Dodge Dealer 1961. I have a short resume though : Pumper to bumber mechanic Cars and Trucks, with a few factory schools to go with the resume. Used allen equipment exclusively at the dealearship,



Guido.
 

This modern technology may take years to catch on :)...

Back to the 9.6 threshold its hard to tell a man he needs a battery when his car is starting just fine but falls just a above 9V on a load test. I have seen bats go for years in this scenario.. The one thing they all have in common is lost of storage capacity but as I stated if all your ducks are in a row the reserve may not be needed. Of course it may be needed when you need it to start at the most inconvenient time its your call.



If the voltage falls under 9V on a fully charged bat its junk no need to make a call its junk I can state its junk and feel good about it. I can point to a sign on the wall that states "WARRING TO AVOID INJURY DON'T TELL ME HOW TO DO MY JOB"

One thing it does affect is it over works the alternator that's not a real biggie until the alt cost over $200 and is extremely labor intensive to replace.

One other thang to take into consideration is how the voltage jumps back to a fully charged state.

A short load test are just hitting the starter for 5 seconds dose the voltage go back to the recorded voltage before this test. If not you have a weak battery.

I would say 50% of my battery sales come from when I start a car and pull it into the shop I can tell by the sound of the starter the bats low. I recommend everyone learn what it sounds like when its in good operation and look for the cause when it does not sound normal, Most bats die slow that's your sign...


For those that are new to this modern technology you can also do a starter amp draw test with this load tester... Who'da tunk'it...
 
Well sir, DC electrical power is a measurement of Watts consumed/dissipated which is VA. If I'm measuring the A at 150-200 Amperes and the V is 12.75 fully charged pulled down to 11V or less there is 1.75V X the A flowing, dissipated inside the battery (primarily) across the sulphated scale and that's power dissipated and the energy consumed at the going rate will be dissipated in the form of heat.....262-350 watts or more if the terminal voltage drops lower than 11v in my case.

Again I don't care about the storage capacity, CCA, H2SO4 to H20 ratio or level in the cells, hydrometer test value or any of that stuff. All I want to know is: Can the battery deliver 1.5 to 2.0 kW (10V x the Amperage figuring 1 volt lost in the interconnect wiring) to a starter for 15 seconds or so.
 
I've never heard of load testing a 6 volt battery at half of it's capacity. A load test is to determine if a battery will maintain a load for 15 seconds with out the voltage dropping below the specified volts. You never crank an engine longer than 15 seconds for the same reason.
A battery load tester is the same as using a hydraulic load tester on a hydraulic system to see what the maximum pressure the pump will put out for a given time frame.
The mathematical formula for figuring out hydraulic flow & pressure is the same formula used in electrical circuits to figure out current flow and voltage (pressure). So why wouldn't you test a battery to its fullest capability???
 
I should have added this to my first comment.
If you have a traactor or any vehicle that the starter draws 300-500 amps when cranking the engine over why would you only load test the battery say at 200 amps? The battery will test good under the small load but when put in actual use it falls flat on its face. A load test needs to be dialed up to the battery's full potential to see if it will hold its maximum output for 15 seconds. It should be fully charged though before doing this.

People look at CCA cold cranking amps now days as the battery's capabilities. I look at that more as a sales pitch.

Amp hours is what you want to know about a battery. Whhich means how long (Hrs) will a battery last under a given load, just like load testing with with a carbon pile load tester.

If your charging system fails it's nice to know how much time you have before your battery goes dead and leaves you stranded. New vehicles today will shut down long before battery voltage drops to 9.6 volts on a 12 volt system. Note I say 9.6 volts because that is the minimum for a 12 volt battery on a load tester. If it doesn't hold 9.6 volts it's considered a bad battery.
 
Hello Hobo,SC,

It also takes years to learn how a stater or an engine does not sound normal. Hard enough to teach it in
person, here?. Half truth, wifes tales, poor understanding of the basics. I could go on and on. You posted
the meter with the voltage markings HELLO!!! The light may be on, but........




Guido.
 
Hello Ted in NE-OH,

Testing starter motor amp draw is easy with an amp probe. Just clamp it around a wire and read the meter,


Guido.
 
(quoted from post at 19:49:21 10/23/16) Don't amp probes work like a transformer and only for AC ??
ou can also get ones that work on DC, but they are so sensitive to magnetic fields you have to keep them away from starter or generator when they are operating. Prices very from $30 to $300 depending on manufacturer and quality.
 
(quoted from post at 00:35:47 10/20/16) Harbor Freight has a 500 amp carbon pile battery tester, anyone have one and tried it on a 6 volt battery? Did it work>

Do a search on amazon and search fod a dc amp probe. About$90

It will do AC and DC amps. I have old style ones but I can't post picture of them as the web site is down. Let me know if you find it if not, I will go back and get you the item number,

Guido.
 

Here are the pictures of my two amp testers. 600 amps gauge is for staring current, while the 75 apms one is for alternator output.
Not big enough for today's alternators, back in the sixties was the cat's meaw!....????


Guido
41843.jpg
41844.jpg
 

Here are the pictures of my two amp testers. 600 amps gauge is for staring current, while the 75 apms one is for alternator output.
Not big enough for today's alternators, back in the sixties was the cat's meaw!....????


Guido
41843.jpg
41844.jpg
 

Here are the pictures of my two amp testers. 600 amps gauge is for staring current, while the 75 apms one is for alternator output.
Not big enough for today's alternators, back in the sixties was the cat's meaw!....????

Guido.
41845.jpg
 
(quoted from post at 00:35:47 10/20/16) Harbor Freight has a 500 amp carbon pile battery tester, anyone have one and tried it on a 6 volt battery? Did it work>

Hello Ted in NE-OH,

Here are my old amp gauges, for starter and alternator output and load testing,

Guido.
41846.jpg
 
Hello

I need to apologize as I see a lot of posting for a click on the modern side. I don't think it was me? I could not post pictures here so I did it on the modern side........Sorry!

Guido.
 
If you are answering me it's because that's all it takes at 12v for my largest engines.

Were my systems 6v, like back in the 50's and early 60's then you would need the scale as shown for double the amperage.

Again a certain horsepower is required to spin the starter on a given engine at a certain rate. HP is measured as (torque x rpm)/5252 or in kilowatts with one HP equal to 0.746 kiloWatts. If the measurement is made over time then it is HP-hours and in kiloWatts is kilowatt-hours.

I am not familiar with the mechanisms shown as to how DC is measured. Usually for high currents a "shunt" is employed that is many times the cross sectional area of the current carrying conductor for a given current so that the shunt will offer minimum resistance in the circuit and won't cause a voltage drop which would reduce the accuracy of the measurement.

The resistance of the shunt is usually stamped on the device and to operate it you wire the shunt in series with the circuit and measure the voltage drop across it's terminals. Using ohm's law you find the current flowing.
 

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