Their tester is finding out what your battery is capable of delivering, as opposed to what it was originally rated at. That can be a valid test, but it is definitely not the way most of us test batteries. That's like testing my shoe and finding it's a size 9 when it's supposed to be a size 10. What I want to know is if there's a hole in the bottom or if the sole is about to tear off.
The battery that came originally in my 1980 Volare was rated at a puny 335 CCA and it performed perfectly for over five years. My 2014 Ram came with an over-size 850 CCA battery. To save money, I replaced it with a 750 CCA battery, and that one is also working just fine. The point I'm not doing a good job of making is you could have two batteries that can each deliver a maximum of, lets say, 600 CCA. One could be rated at 550 CCA so it's doing a really good job, and the other one could be rated at 850 CCA, but it's old and tired. According to the way they tested your battery, both are in good shape, but in reality, the larger battery is partially used up. This is why we normally don't test a battery to see what it can develop. We test it against itself compared to when it was new. That's what I mean by "CCA is an input" to the calculation. Instead of seeing what the battery can develop at that instant, we enter the CCA rating into the tester, then see if it can develop half of that current for 15 seconds. Time is an important variable because this is a standardized test, but that isn't considered with the test they did.
We also need a standardized test to be able to compare two batteries to each other. Back in the 1960s Radio Shack advertised a little pocket transistor radio that could develop 50 watts of power. In truth, it was lucky if it could develop a half a watt of power, but for this test, they were able to squeeze that 50 watts out for one musical note, then the radio melted into an overheated puddle. It did indeed develop a 50-watt spurt, so it must be just as powerful as the Kenwood or Pioneer amps. Time wasn't considered because it wasn't a standardized test. What you got might be valid, but it's not a standardized test.
What your test result of 525 CCA tells me is your battery is fine, especially if it is a year old or more. It is unrealistic to expect it to be able to develop 600 CCA for all of its life. I get slower as I get older, and so do batteries as the lead flakes off the plates.
I'm suspicious there's something else coming into play. The first problem is with charging the battery. If it was nearly fully-run down, it takes a good 15 to 20 minutes on a charger before it starts to take a charge. You'll see the amp meter sit on "0" at first. It takes some time before the acid becomes conductive, and the electrons start to be absorbed into the plates. After that initial 15 - 20 minutes, you'll see the amp meter go higher and higher. With really huge battery store industrial chargers, we consider a bank of batteries to be fully-charged when the current drops to an average of five amps per battery. Any charging after that will just warm up the acid excessively and boil the water out of it. If your battery was totally dead, it needs to be charged at a slow rate for at least a couple of hours before it is tested.
I have to point out another potential problem related to charging batteries. In cars, the charging systems put out three-phase output which is fairly steady and easy for the battery to smooth out. Home battery chargers take the house current's sine wave, rectify that, then apply that to the battery. That voltage goes from 0 volts to maximum, then back to 0 volts 120 times per second. When you apply that to the battery, the pulsing current vibrates the plates. At high charge rates, it vibrates the plates a lot. In all batteries, the lead flakes off the plates over time. Battery manufacturers know how fast that happens. It can't be avoided, but since they know how long they can expect the battery to last before a cell shorts, they give you the longest warranty possible
When you charge the battery at a fast rate, any loose lead gets vibrated off the plates faster. That doesn't cause a battery to fail. It just shortens the time before the battery fails. This is worse for older batteries.
As a point of interest, if you're worried about your battery, I found an almost fool-proof way to know when a battery is about to fail. Look for the white corrosion around the posts and terminals. If there is none, there is nothing to be solved or prevented by using the juicy rings or battery post treatments. If you do see that corrosion, the battery is likely going to fail within six months, and those chemical treatments aren't going to prevent that.
What I learned is as the lead flakes off the plates, there is, in effect, less battery, but the charging system is still charging it as though it was new. With the same amount of charging current going in, but less lead to absorb the electrons, the plates and acid heat up more than normal. That causes excessive bubbling, and it's those bubbles that rise to the under-side of the top of the case, and pop there. That sprays the case with acid, and that is what migrates out alongside the posts and forms that corrosion. Treating the posts for corrosion doesn't stop more from forming there, and neutralizing it doesn't stop the bubbling inside from the loss of lead in the plates. The battery is doomed, and I was able to predict that at the dealership with very high accuracy.
The last variable is the 9.6 volts volts I mentioned earlier. That is another part of the standardized test. Since I don't do the type of test you had done, I don't know if they have any requirement for that. This is like that transistor radio test. I guarantee I can get your battery to deliver well over 2,000 amps which is more than enough to start a diesel engine on a cold day, but not when the voltage has been drawn down to almost nothing. Your sad battery might not fully recover from that, but it proved it could develop a lot of current, so it must be good, right? Most older GM and Ford starters commonly drew enough current to drag the battery's voltage down to near 9.6 volts, and that was still enough to run the ignition system and crank the engine fast enough to get it started. That's how that magic number became part of the standardized test.
If an unscrupulous battery salesman wanted to sell you a new battery, all he has to do is load it down to 11.0 volts, at which time it might not even reach 200 amps. Therefore, it's bad. He could also show you his battery under test. That ones gets loaded down s hard it develop 1,000 amps before your eyes, but he holds his hand over the volt meter so you can't see it got drawn to 5.0 volts.
There's one last thing I have to point out. All vehicles today draw a small amount of current to keep the memories alive in the multiple computers. As far back as the early '90s, Chrysler used to say it was acceptable to have up to 35 milliamps of "ignition-ff-draw" current when everything was turned off. That's 0.035 amps, and at that rate, they said a good, fully-charged battery would still be strong enough to start the engine after sitting for three weeks. Now that has been adopted as the industry-standard, unless specified otherwise by the car manufacturer. Cadillac is one that allows up to 50 milliamps.
That three weeks is all they'll guarantee, but few cars draw that entire 35 ma. I have a '93 Dynasty with almost every computer-controlled option. It can sit for six weeks and still start, but just barely. That car has less than 5,000 miles so it does sit for quite a while. For cases like that, including when cars are being shipped to the dealers, there is always a means of disconnecting that drain. This might not apply to any aftermarket radio equipment you have, depending on how it was wired, but for factory equipment, there used to be a bullet connector in a single, rather fat wire, right behind the battery. By around the mid to late '90s, they used one fuse under the hood, or a pair of fuses inside. Those are commonly labeled for the "Air Bag" and will be in a bright yellow holder. If you pull that out, all current to the factory equipment will stop.
The bottom line is your friend is right. Your battery might not have been fully-charged when it was tested. I have nothing to compare your test results to the way I test batteries. All batteries are less able to develop the current they were designed for as the get older. And, I'd be proud to be able to get 525 CCA out of the battery in my sad, rusty minivan, and I'm up north where we forget what summer feels like!
Wednesday, January 15th, 2020 AT 6:43 PM
