New School vs Old School (Battery Testing)
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Date: 2025-05-27
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Comments and reviews: 20
bettyg7710
The problem with the electronic testers is they can’t test for a low or dead cell. A battery hydrometer is the only test for this, but manufactures want you to buy batteries and they do not want to warranty them. So what do is, they don’t provide fill caps so you can’t keep your battery topped off with acid and check for bad cells anymore. The electronic tester can only check charge state and capacity and dead shorts, but they can not check a single cells viability, that is it’s ability to take and hold a charge.
So what happens, you go back to the store they test your failing battery and tell you its good and won’t warranty it. This makes you go buy a new battery somewhere else because you know when you go to start your car tomorrow with the tested battery your car won’t start. If you go buy a battery, make sure it has cell caps you can remove to test. I saved a customer of mine from this when I used a hydrometer to test his battery from one of the local parts stores. He brought his car in with a slow crank or no crank in the mornings. I put his battery on charge. After charging I tested it and it had a bad cell according to the hydrometer test. Since the store he bought it from was close by he took his battery there to get it replaced under warranty, he came back mad because they told him the battery was good and they would not replace it.
I put my tester in my pocket and went to the store with my customer and I showed the manager of the store how his electronic tester was wrong and the battery in question was indeed bad. The manager agreed and replaced the battery for free.
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The problem with the electronic testers is they can’t test for a low or dead cell. A battery hydrometer is the only test for this, but manufactures want you to buy batteries and they do not want to warranty them. So what do is, they don’t provide fill caps so you can’t keep your battery topped off with acid and check for bad cells anymore. The electronic tester can only check charge state and capacity and dead shorts, but they can not check a single cells viability, that is it’s ability to take and hold a charge.
So what happens, you go back to the store they test your failing battery and tell you its good and won’t warranty it. This makes you go buy a new battery somewhere else because you know when you go to start your car tomorrow with the tested battery your car won’t start. If you go buy a battery, make sure it has cell caps you can remove to test. I saved a customer of mine from this when I used a hydrometer to test his battery from one of the local parts stores. He brought his car in with a slow crank or no crank in the mornings. I put his battery on charge. After charging I tested it and it had a bad cell according to the hydrometer test. Since the store he bought it from was close by he took his battery there to get it replaced under warranty, he came back mad because they told him the battery was good and they would not replace it.
I put my tester in my pocket and went to the store with my customer and I showed the manager of the store how his electronic tester was wrong and the battery in question was indeed bad. The manager agreed and replaced the battery for free.
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Deano_Bambino2500
The discrepancy in battery test results, with modern testers showing a good battery but the load test dropping the voltage to 2 volts, suggests a failing battery that can still hold a nominal voltage under light loads but fails under load. This can happen due to factors like internal resistance buildup, sulfation, or damaged plates that prevent the battery from delivering sufficient current.
Elaboration:
Modern Testers vs. Load Testers:
Modern battery testers often measure open-circuit voltage and internal resistance, providing a general indication of battery health. However, they may not accurately represent the battery's ability to deliver current under a real-world load like starting a vehicle.
Load Test Failure:
A load test applies a known load to the battery, simulating the demands of starting an engine. If the voltage drops significantly (like to 2 volts, it indicates that the battery is unable to provide the necessary current to meet the load, even though it may have shown a good voltage reading under light loads.
Causes of Load Test Failure:
Internal Resistance: Over time, internal resistance in a battery increases, making it harder for the battery to deliver current.
Sulfation: Sulfation, the formation of lead sulfate crystals, can reduce the battery's capacity and make it more difficult to deliver current.
Damaged Plates: Internal damage to the battery plates can also lead to a decrease in performance under load.
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The discrepancy in battery test results, with modern testers showing a good battery but the load test dropping the voltage to 2 volts, suggests a failing battery that can still hold a nominal voltage under light loads but fails under load. This can happen due to factors like internal resistance buildup, sulfation, or damaged plates that prevent the battery from delivering sufficient current.
Elaboration:
Modern Testers vs. Load Testers:
Modern battery testers often measure open-circuit voltage and internal resistance, providing a general indication of battery health. However, they may not accurately represent the battery's ability to deliver current under a real-world load like starting a vehicle.
Load Test Failure:
A load test applies a known load to the battery, simulating the demands of starting an engine. If the voltage drops significantly (like to 2 volts, it indicates that the battery is unable to provide the necessary current to meet the load, even though it may have shown a good voltage reading under light loads.
Causes of Load Test Failure:
Internal Resistance: Over time, internal resistance in a battery increases, making it harder for the battery to deliver current.
Sulfation: Sulfation, the formation of lead sulfate crystals, can reduce the battery's capacity and make it more difficult to deliver current.
Damaged Plates: Internal damage to the battery plates can also lead to a decrease in performance under load.
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Garth2011
I purchased a hand held electronic battery analyzer and its not truly accurate. I tested a 7 year old battery on my daily driver and the end results were replace battery. The engine still turned over and started for another 2 years and every now and then I had used that analyzer with the same results. Finally, at 10 years old, I replaced the battery that continued to start the engine thinking that I'm on the edge by now. Tested the new one and it passed. This was a Topdon $60 analyzer so I figured it is looking at more data than just starting capacity but once an engine is started, the electrical system technically run off of the alternator. I also went to a battery only sales supply and they put on the old amp load tester and said the battery shows a little off normal but was still considered useable, this was at year 8. My past experience says a battery tester will guesstimate where your battery state is but it won't tell you how much longer it will function. I have had batteries show full state of charge yet won't produce 30 amps and fall completely down to nothing at the time. I have had functional batteries give no warning and test as normal and the next day, no start. Computer cars are much different and require top performing batteries at all times so lead acid isn't going to last as long with those but our older vehicles will.
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I purchased a hand held electronic battery analyzer and its not truly accurate. I tested a 7 year old battery on my daily driver and the end results were replace battery. The engine still turned over and started for another 2 years and every now and then I had used that analyzer with the same results. Finally, at 10 years old, I replaced the battery that continued to start the engine thinking that I'm on the edge by now. Tested the new one and it passed. This was a Topdon $60 analyzer so I figured it is looking at more data than just starting capacity but once an engine is started, the electrical system technically run off of the alternator. I also went to a battery only sales supply and they put on the old amp load tester and said the battery shows a little off normal but was still considered useable, this was at year 8. My past experience says a battery tester will guesstimate where your battery state is but it won't tell you how much longer it will function. I have had batteries show full state of charge yet won't produce 30 amps and fall completely down to nothing at the time. I have had functional batteries give no warning and test as normal and the next day, no start. Computer cars are much different and require top performing batteries at all times so lead acid isn't going to last as long with those but our older vehicles will.
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SPAZTICCYTOPLASM
The reason you get funky results I think is because the internal resistance testers aren't checking the right thing all the time, and I'm pretty sure it's because the old school draw testers can damage modern cars electronics because they just short the battery through a heater coil, which apparently can cause some funny results with modern electronics in cars. The new stuff exists because it's safer and less likely to cause damage to fancy cars, but the old tester is testing the actual output of the battery. That said, you'd really wanna use both. You don't wanna run a battery with high internal resistance even if it's got good output. High internal resistance can cause hydrogen build up and boom! or just heating up and damage leaks etc etc. One isn't a replacement for the other, it's like a multimeter isn't a replacement for a simple test light, even if it can be used that way for 99% of cases.
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The reason you get funky results I think is because the internal resistance testers aren't checking the right thing all the time, and I'm pretty sure it's because the old school draw testers can damage modern cars electronics because they just short the battery through a heater coil, which apparently can cause some funny results with modern electronics in cars. The new stuff exists because it's safer and less likely to cause damage to fancy cars, but the old tester is testing the actual output of the battery. That said, you'd really wanna use both. You don't wanna run a battery with high internal resistance even if it's got good output. High internal resistance can cause hydrogen build up and boom! or just heating up and damage leaks etc etc. One isn't a replacement for the other, it's like a multimeter isn't a replacement for a simple test light, even if it can be used that way for 99% of cases.
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SouthMainAuto
I have noticed that a small percentage of the batteries being tested with an internal resistance style digital tester are some time inaccurate. They will give you a actual CCA, voltage reading along with state of health and state of charge and a nifty little print out for you customer. The better units have the ability to test flooded and AGM batteries as well. More often than not they work great and seem to be accurate. As mentioned in the video there are times when it can test good or even perfect but does not have enough amperage to start the vehicle. What I am getting at is use it as a piece of test equipment but not the only piece of test equipment. It sure is hard to beat a good old fashion carbon pile tester when checking the batteries ability to put out.
-Enjoy Your Day: -)
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I have noticed that a small percentage of the batteries being tested with an internal resistance style digital tester are some time inaccurate. They will give you a actual CCA, voltage reading along with state of health and state of charge and a nifty little print out for you customer. The better units have the ability to test flooded and AGM batteries as well. More often than not they work great and seem to be accurate. As mentioned in the video there are times when it can test good or even perfect but does not have enough amperage to start the vehicle. What I am getting at is use it as a piece of test equipment but not the only piece of test equipment. It sure is hard to beat a good old fashion carbon pile tester when checking the batteries ability to put out.
-Enjoy Your Day: -)
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psychodad1961
I had that happen several years ago. Bought a walmart battery and just a few months later I was cleaning out my car and had the radio playing on Accessory for about 15 minutes while I vacuumed. Damn if I wasn't stranded at the car wash. Took it back to walmart and they put their little tester on it and denied any warranty saying it was still good. I parked it facing the door and left the headlights on for 7 minutes. Car wouldn't start. They retested and it still said good on their battery tester. So the tech says Sumpin' wrong wich yo car. I looked at him and laughed. It took a call to corporate to get my new battery. BTW, I was (in my younger days) a state certified automotive electrician specializing in troubleshooting and CAN BUS diagnostics.
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I had that happen several years ago. Bought a walmart battery and just a few months later I was cleaning out my car and had the radio playing on Accessory for about 15 minutes while I vacuumed. Damn if I wasn't stranded at the car wash. Took it back to walmart and they put their little tester on it and denied any warranty saying it was still good. I parked it facing the door and left the headlights on for 7 minutes. Car wouldn't start. They retested and it still said good on their battery tester. So the tech says Sumpin' wrong wich yo car. I looked at him and laughed. It took a call to corporate to get my new battery. BTW, I was (in my younger days) a state certified automotive electrician specializing in troubleshooting and CAN BUS diagnostics.
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autorepair
Try and get a battery replace that won't start your vehicle while still under warranty. They have to charge your battery then test it. They always show good when they are junk. I took my carbon pile tester with me after they did there test and boom 5 seconds in if not less it went to zero. What they are only testing is the surface charge. After my test they tested it again with there fancy new crap and it showed good. I told them if it won't start the vehicle it's junk. They all play this battery game with you. I took it and bought a new battery and used that as a core. Warranty don't mean shit now days on battery. Been like this for over 10 years if not longer. Don't even bother to pay extra for a few more years cause it will always show good to them.
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Try and get a battery replace that won't start your vehicle while still under warranty. They have to charge your battery then test it. They always show good when they are junk. I took my carbon pile tester with me after they did there test and boom 5 seconds in if not less it went to zero. What they are only testing is the surface charge. After my test they tested it again with there fancy new crap and it showed good. I told them if it won't start the vehicle it's junk. They all play this battery game with you. I took it and bought a new battery and used that as a core. Warranty don't mean shit now days on battery. Been like this for over 10 years if not longer. Don't even bother to pay extra for a few more years cause it will always show good to them.
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Dje4321
CCA DOES NOT EQUAL BATTERY CAPACITY. This matter alot especially on vehicles with long crank times
CCA is just the battery's ability to dump it's entire charge as fast as possible. As the internal resistance goes up, the CCA goes down but the total capacity can stay the same. A battery at 1% capacity can still happily deliver 350CCA but only do it for 5 seconds before going flat.
To check capacity, you need to perform a load cycle test on it. Basically full charge it, put a constant 1-5A load on the battery and see how fast it dies. A 5 amp load should drain a fully charged lead acid battery in 12-24hrs depending on capacity. If your 5A load drains the battery in 10 hours, then you have 50Ah of capacity remaining in the battery.
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CCA DOES NOT EQUAL BATTERY CAPACITY. This matter alot especially on vehicles with long crank times
CCA is just the battery's ability to dump it's entire charge as fast as possible. As the internal resistance goes up, the CCA goes down but the total capacity can stay the same. A battery at 1% capacity can still happily deliver 350CCA but only do it for 5 seconds before going flat.
To check capacity, you need to perform a load cycle test on it. Basically full charge it, put a constant 1-5A load on the battery and see how fast it dies. A 5 amp load should drain a fully charged lead acid battery in 12-24hrs depending on capacity. If your 5A load drains the battery in 10 hours, then you have 50Ah of capacity remaining in the battery.
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williamzwit4308
I would guess the electronic testers are not a live load. The pile testers though are actually a live load. Given any battery be it charged or slightly below charge has a voltage at rest. AGM batteries recover very quick. Lead-acid design recover quick when new. You put some time on the battery, the at rest voltage degrades sutle steps. The need to remove the vehicle terminal clamps to test resting voltage is important. Placing a live load on battery for seconds then remove to see recovery voltage is really a great indicator of its health. Yes, using live load testers is the way to go.
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I would guess the electronic testers are not a live load. The pile testers though are actually a live load. Given any battery be it charged or slightly below charge has a voltage at rest. AGM batteries recover very quick. Lead-acid design recover quick when new. You put some time on the battery, the at rest voltage degrades sutle steps. The need to remove the vehicle terminal clamps to test resting voltage is important. Placing a live load on battery for seconds then remove to see recovery voltage is really a great indicator of its health. Yes, using live load testers is the way to go.
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thomasherring6640
I had a very similar experience with Advance Auto. Battery would usually start my car, but if I left the ignition on for a minute or kept the door open too long it was all she wrote. I checked all my connections to make sure there wasn't anything loose or corroded, all good. Battery was only a year and a half old. Went to Advance, they tested it, it was fine according to their machine. Thankfully, they guy agreed to warranty it anyway. Swapped the new battery in, car has been fine since, so clearly the old battery was the problem, yet it tested at like 85% health.
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I had a very similar experience with Advance Auto. Battery would usually start my car, but if I left the ignition on for a minute or kept the door open too long it was all she wrote. I checked all my connections to make sure there wasn't anything loose or corroded, all good. Battery was only a year and a half old. Went to Advance, they tested it, it was fine according to their machine. Thankfully, they guy agreed to warranty it anyway. Swapped the new battery in, car has been fine since, so clearly the old battery was the problem, yet it tested at like 85% health.
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ssboot5663
I USE AN Old school toaster oven resistance tester here to tell the real truth about what a battery will or wont do. . Digital testers are so NAPA and TSC don't have to warranty a failing battery. JUST like the phrase they use. an alternator wont charge your battery even if you drive it for a few hours) Then they proceed to tell you that you need to charge it on a big charger. Digital testers are hocus pocus. I mean really, who needs a print out machine on a battery tester anyway It either works like it should over some time of sitting unused or it don't.
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I USE AN Old school toaster oven resistance tester here to tell the real truth about what a battery will or wont do. . Digital testers are so NAPA and TSC don't have to warranty a failing battery. JUST like the phrase they use. an alternator wont charge your battery even if you drive it for a few hours) Then they proceed to tell you that you need to charge it on a big charger. Digital testers are hocus pocus. I mean really, who needs a print out machine on a battery tester anyway It either works like it should over some time of sitting unused or it don't.
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jimgale8465
I'm an old fashioned guy who was taught to do individual cell voltage tests when the battery was at rest. of course this with an appropriate load test. 3x's AH rate or 1/2 CCA for 15 seconds and during the load the battery voltage couldn't drop below 9. 6v
Now with sealed cells, and techs who don't understand a volt/amp/tester this is all voodoo. And if the battery is discharged it has to charged.
But the basic understanding of the VAT, gives you skills for voltage drop tests, and the ability it easily test draw.
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I'm an old fashioned guy who was taught to do individual cell voltage tests when the battery was at rest. of course this with an appropriate load test. 3x's AH rate or 1/2 CCA for 15 seconds and during the load the battery voltage couldn't drop below 9. 6v
Now with sealed cells, and techs who don't understand a volt/amp/tester this is all voodoo. And if the battery is discharged it has to charged.
But the basic understanding of the VAT, gives you skills for voltage drop tests, and the ability it easily test draw.
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autorepair
I have a small digital battery tester I bought on eBay and it works really well. I have two batteries on my 4WD and it tested one as faulty and the other okay which is exactly what it was. However, I have not got any older devices to check against. However, that all said, I think you are exactly right, old school stuff was made to do a job and it did it well. New stuff is is used in too many different applications that they don't do one job very well. A bit like a jack of all trades but a master of none.
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I have a small digital battery tester I bought on eBay and it works really well. I have two batteries on my 4WD and it tested one as faulty and the other okay which is exactly what it was. However, I have not got any older devices to check against. However, that all said, I think you are exactly right, old school stuff was made to do a job and it did it well. New stuff is is used in too many different applications that they don't do one job very well. A bit like a jack of all trades but a master of none.
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lithgowlights859
My cheap tester says for best results remove from the car and do NOT apply a charge within 4hours of testing. When I test a battery thats been freshly charged it seems to test at or at least very close to the CCA rating, and have low internal resistance. Test that same battery the next morning after being off the charge (Way above freezing here at night) and it's down to 60% of the CCA rating and much higher internal resistance, so I think some are affected by the surface charge.
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My cheap tester says for best results remove from the car and do NOT apply a charge within 4hours of testing. When I test a battery thats been freshly charged it seems to test at or at least very close to the CCA rating, and have low internal resistance. Test that same battery the next morning after being off the charge (Way above freezing here at night) and it's down to 60% of the CCA rating and much higher internal resistance, so I think some are affected by the surface charge.
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dagamer667
Trouble is, none of these internal resistance testers measure the capacity loss. This is usually listed as Reserve Capacity (RC) on the battery or a straight AH. I work at AutoZone and one the extra tests I like to do on batteries with a sus PASS result is have the customer turn the key to ON, leave their headlights on for five minutes, and then attempt to start the vehicle. Seen way too many batteries that passed the official tester only to struggle or flunk the headlights test.
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Trouble is, none of these internal resistance testers measure the capacity loss. This is usually listed as Reserve Capacity (RC) on the battery or a straight AH. I work at AutoZone and one the extra tests I like to do on batteries with a sus PASS result is have the customer turn the key to ON, leave their headlights on for five minutes, and then attempt to start the vehicle. Seen way too many batteries that passed the official tester only to struggle or flunk the headlights test.
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autorepair
Yes I agree the resistance style testers are ok, most of the time, but some times the carbon pile will show it true state, and years in the trade is also a very accurate assessment of a battery, most times I have a gut feeling the battery is no good, more often than not it turns out to be no good, even if it a week later. ( 43 years in trade )
The very little cheap resistance style testers, well I think the kettle in the lunch room has got a better chance of being accurate.
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Yes I agree the resistance style testers are ok, most of the time, but some times the carbon pile will show it true state, and years in the trade is also a very accurate assessment of a battery, most times I have a gut feeling the battery is no good, more often than not it turns out to be no good, even if it a week later. ( 43 years in trade )
The very little cheap resistance style testers, well I think the kettle in the lunch room has got a better chance of being accurate.
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terryshireman4271
My sons van had to jump start it so we had it tested at AutoZone they said battery is bad alternator n starter is good so installed new battery a week later same issue won't hold a charge all cables n connectors clean n tight so we had the alternator bench tested at AutoZone again they claimed alternator is good so I bought a new alternator online installed it n presto van holds a charge for years. This new testing technology is crap sometimes.
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My sons van had to jump start it so we had it tested at AutoZone they said battery is bad alternator n starter is good so installed new battery a week later same issue won't hold a charge all cables n connectors clean n tight so we had the alternator bench tested at AutoZone again they claimed alternator is good so I bought a new alternator online installed it n presto van holds a charge for years. This new testing technology is crap sometimes.
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x1tekja
The thing with the new gizmos is they don't put any kind of load on the batteries. All they really are is a chip and a program. They will give you a basic readout. However they will give you some false positives and negatives.
Tested a brand name battery on my tractor that sat. Battery was three years old and digital meter said it was cooked. Brought out the 50 year old charger with built in gauges. Charged it up and battery is working fine.
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The thing with the new gizmos is they don't put any kind of load on the batteries. All they really are is a chip and a program. They will give you a basic readout. However they will give you some false positives and negatives.
Tested a brand name battery on my tractor that sat. Battery was three years old and digital meter said it was cooked. Brought out the 50 year old charger with built in gauges. Charged it up and battery is working fine.
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ranger178
i found my tester gives a surface charge reading of battery that was recently charged or run way better than it actually is. if you check it on day after it has been charged or run it will drop in one day from 98 % charge to 65% and from 100% healthy to 90. If i have battery charge all day then test it next day it give more accurate reading the car sits a lot and slowly loses charge so it needs 8 hours with a small charger to really charge it up
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i found my tester gives a surface charge reading of battery that was recently charged or run way better than it actually is. if you check it on day after it has been charged or run it will drop in one day from 98 % charge to 65% and from 100% healthy to 90. If i have battery charge all day then test it next day it give more accurate reading the car sits a lot and slowly loses charge so it needs 8 hours with a small charger to really charge it up
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LTGOneill
less than a week ago, similar results; 2020 camry with factory battery, needed jump pack to start, also took it to the zone, they said it tests fine, I said sure try to start it, no start, put a jump pack it starts instantly. I just said give me a new battery anyway, swapped battery, started fine, no problems since. those new testers are not reliable, but if you want warranty on a battery they'll say it's good so you can't win either way.
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less than a week ago, similar results; 2020 camry with factory battery, needed jump pack to start, also took it to the zone, they said it tests fine, I said sure try to start it, no start, put a jump pack it starts instantly. I just said give me a new battery anyway, swapped battery, started fine, no problems since. those new testers are not reliable, but if you want warranty on a battery they'll say it's good so you can't win either way.
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