Car battery tested 12.4 v, 578 cca/640 and 61% state of charge?

It's normal for the battery to run down when sitting, especially on a vehicle as new as this. Short trips will also run it down faster than it can recharge. New vehicles have dozens of computer modules. Most of them have memory circuits that draw a little current when turned off to keep those memories alive.

As far back as the late 1980s, Chrysler allowed up to 35 milliamps, (0.035 amp) of drain for those memory circuits. They said at that rate, a good, fully-charged battery would be strong enough to start the engine after sitting for three weeks. Today that has become the industry standard unless the manufacturer specifies otherwise. Cadillac, for one, allows up to 50 milliamps. I have a '93 Dodge Dynasty that sits in storage most of the time. I found it can sit for at least six weeks and still start. Also have a 2014 Ram that recently sat unused for two and a half months. It barely started without a jump-start, but it did start. Can't say that for my 2014 Grand Caravan daily driver. I put a battery maintainer on it if it's going to sit unused more than two weeks. That battery is 12 years old, so it won't have the storage capacity of a new battery.

To add to the problem, your vehicle likely uses an "AGM", (absorbed glass mat) battery. Those hold up better, but they don't have liquid electrolyte as was used since forever. That makes it harder for the explosive hydrogen gas that all batteries develop to escape. For that reason, there are circuits designed to limit, or slow down how rapidly they recharge after starting the engine. That's why multiple short trips won't give the battery enough time to recharge. If this sounds like it applies to your battery, consider connecting an inexpensive battery maintainer. That's what I use on My Caravan. I have to plug that in, but there are models that are solar-powered. Once connected to the battery, all that's needed is to park the vehicle in a place where the solar panel can see sunlight.

Ok so is the battery good then?

I had visited a local mechanic and he recommmended simply taking it for a 30min drive to recharge and it should be good. Cars only a year old and battery tested 12.4 volts and 90% for condition state

Are you having a problem? A good, fully-charged battery will measure 12.6 volts. A good battery that is totally discharged will be close to 12.2 volts. Your mechanic is right. Based on what you described, with long periods of non-use, and with short trips, the battery is not going to be at full charge. Also, AGM batteries are designed to recharge at a rather slow rate to reduce how fast hydrogen gas is developed. If you're having starting trouble, use the battery maintainer I mentioned.

Let me know if you're having a problem.

There is no problem, I also asked the mechanic if we could replace the battery and he empathized that it was good and didn’t need to be replaced just to drive it more frequently so that’s what we have been doing.. I drove about 6 miles a day for the past 3 days straight

Also they had inspected my car yesterday at pep boys in addition to the other mechanic when I had my alignment and both gave me the all clear on the battery never mentioned needing replacing. The first mechanic that did our multipoint inspection couldn’t stress enough how much we just needed a 30min drive or 5mi drive and not to replace the battery , I asked so can we just replace it and he swore it was a good battery and wouldn’t need any replacing

That sounds exactly right. There is no problem or defect, and you'd have the same results with a new battery. AGM batteries are what almost all new vehicles come with for the last ten to twelve years. They need to charge at a slower rate than what we were used to, but even the older-style lead-acid batteries needed a good ten to twenty miles to charge back up after starting the engine. AGM batteries seem to last a lot longer too. With older batteries, you were doing really well if you could get five years out of them. My Caravan battery lasted 12 years. Instead of sudden total failure one morning, you're more likely to notice needing a jump-start the first start of the day will gradually become more frequent as the battery nears the end of its life. The way I measured my battery was by how long I could power my laptop in a parking lot before the car battery was too run down to start the engine. That used to be as much as two hours, but lately it's down to less than 15 minutes.

I'm a vendor at the nation's second largest old car show swap meet, and remember hearing stories about how it was normal practice once or twice a month to have to charge the car's battery, either at home or at a shop. Before Chrysler developed the "alternator" for their 1960 models, the older generators were terribly inefficient. People said it was common to need over 100 miles of steady driving to keep the battery charged. Thank goodness those days are gone, but it's funny how a lot of "new" technology mirrors what we put up with a long time ago. (We think electric cars are the wave of the future, but they were more common in the early 1900s than were gas-powered cars). Today you'll find battery maintainers in every hardware store, auto parts store, farm and home store, and Walmart. There was little need for them before AGM batteries showed up.

To boil this sad story down, AGM batteries offer the biggest design improvement that we've seen in probably the last 50 years, but they do have limitations. If you start noticing slow cranking in a few years, I'd connect a solar-powered battery maintainer, even if it can only see the sun when you drive it out of the garage. It can help the battery stay more charged while you're in the grocery store.

Ok but regarding the condition being 90% and the battery coming back as ok does that mean it’s ok? As in it should last? Also would AGM batteries still test in good condition or 90% condition if the battery itself was faulty or discharged? I kept asking the mechanic if it needed replacing and his answer was just drive more frequently with longer trips, which I did, I took the car for a 30min 6mile total spin so I was hoping that could charge it some, it’s just that we don’t take long drives often, as the ride to and from places is usually within a 2miles radius..

The battery overall tested good just needed recharge with 578 out of 640 cca

Your mechanic and I answered these questions multiple times, but you still never said if you were having a problem. This battery should not even be getting tested unless there is a problem you're trying to solve. Your battery does not need to be replaced. A new one can test exactly the same way, especially if you drive the vehicle the same limited amount. If I was asked to test a battery at the dealership for a customer, I'd write on the repair order, "battery tests fine", and leave it at that. To list more details or numbers suggests your mechanic is trying to put your mind at ease. I can think of a hundred more important things to worry about, with the battery being at the bottom of that list. At the top of MY list is getting a nail in a tire, especially when it's cold and snowing outside.

To address the drive you described, there's a good chance that isn't nearly enough. To take 30 minutes to go only six miles suggests this was a lot of city driving. That means low engine speeds. All generators and alternators are very inefficient at low speeds and will not effectively bring the battery to full charge. The older lead-acid batteries recharged a lot faster, but if left sitting for a few days, even they needed a good hour or two at highway speeds to reach full charge.

As for the current the battery is able to develop, don't take those numbers to be the gospel truth. No two batteries are ever exactly alike, but the entire batch gets the same ratings. The "cold cranking amps", (CCA), is the most often used standardized rating method. It specifies what that battery should be able to develop for 15 seconds, without it's voltage, (electrical pressure), falling below 9.6 volts, when it is above the specified minimum temperature. As I recall, that temperature is 32 degrees Fahrenheit. (Some rating methods use 0 degrees). Batteries store and develop electrical energy through a chemical reaction, and those always slow down as temperature drops. That's why temperature is included as one of the variables. With the older-style battery testers, we had to dial up the specified amount of current for 15 seconds, then see if the battery was strong enough to do that. When using cold cranking amps, the industry standard was to try to draw one half of the CCA rating while the voltage stayed at least as high as 9.6 volts. That was real close to mimicking what the battery had to do to run the starter motor. If your battery is rated at 640 CCA, we would turn the tester up to draw 320 amps. To put this in perspective, an older GM or Ford V-8 engine from the 1960s through the 1990s would commonly need around 300 amps to get going, then it would drop a little once it was spinning. (I'd be happy to explain that electrical theory in detail, but you won't be tested on this later). Chrysler engines used a different starter design. Those draw around 200 to 250 amps, so it used to be common when a battery was too old and tired to start a GM or Ford engine on cold days, we'd put that battery in a Chrysler product to get another year out of it.

640 CCA is not a common value to find for a battery rating. They usually end with a "50" or "00", as in 650 CCA, 700 CCA, like that. Regardless, most battery suppliers know what a certain design should be able to develop, then they use every trick to find the best average number, and use that for the entire group. Some batteries will fall a little short. Some will be a little stronger, but all of them will start the engines they're designed for just fine.

To add another dimension to this story, the CCA ratings are not meant to rate the condition of a battery. Every battery becomes just a tiny little bit weaker each time it is used. Those ratings are meant to give you a way to compare what you're getting for your money between different battery brands from different manufacturers, or different battery models from one or more manufacturers. I think of it as comparing gas prices at different stations. If you only look at Shell stations, the prices are likely to be the same, within a cent or two. It's the other brands you want to look at, then, if one station is horribly cheaper than the rest, you have to figure out why and how it affects your car. Dollars is the standard used to do the comparison, then whatever variables affect the price at one station over the others is what is of interest.

I go through a lot of batteries for other projects. To save money, I buy them from auto salvage yards. The last one I bought for one of my vehicles was physically too big to fit in it properly, but it had a CCA rating much higher than what came in that vehicle originally. It worked fine for two years, but then I noticed the starter cranking the engine slower and slower, until it finally forced me to walk back home eight miles! After that, I plugged in a battery maintainer each night that sat under the hood, next to the battery. With that, I got more than another year out of that battery. My daily trips were between eight to ten miles to town, often with multiple stops, then back home. Most of that was at highway speed, but it wasn't enough to keep that battery charged. On those rare days I drove 40 miles to help a friend, the battery charged more, then was good for two or three days.

I'm in Wisconsin where we have a lot of people who head south for the winter. They leave vehicles at home for months at a time, not being driven. There isn't a car alive today that won't run the battery down within a month or two due to all those computers with memory circuits that constantly draw a little current. This is the perfect application for those battery maintainers. Most of them get plugged in to the outlet in the garage, but if the vehicle sits outside, the solar-powered ones are a popular choice. On many car models, the solar panel can sit on top of the dash, then the cable can be plugged into the vehicle's power outlet. I can go into more detail on those too, but your mechanic will be able to tell you if those can work for your car. What you need is a power outlet or cigarette lighter socket that stays live all the time, even when the ignition key is removed. These plug-in-style battery maintainers typically cost less than $20.00. I don't know the cost of the solar-powered models, but I suspect they're about the same. To add a little more confusion, on a lot of newer vehicles like yours, power outlets can remain live after the key is removed, but only until you open a door, or they time out in a minute or two. Often there's a fuse that can be moved to change that and keep the outlet live all the time. That's why your mechanic is the better person to discuss this with.

For my final words of wisdom, the 90% is another number you shouldn't be worrying about. It's just about impossible to find any battery that shows 100% charge. Also, if a battery rated at 640 CCA can develop 578 CCA, it is doing a dandy job. I recently tested the battery in my minivan with a new-style electronic tester. It was rated at 850 CCA when it was new, but now can barely develop 250 CCA. It's 14 years old, and still starts the engine just fine.

I forgot to add another comment of value. On the older lead-acid batteries, it was a fact of life that some of that lead was going to flake off the plates over time. In effect, every battery becomes smaller electrically as it ages. When enough material flakes off and settles in the bottom of the case, when it builds up high enough to touch those plates, it shorts out that cell, then the battery must be replaced. The battery manufacturers knew how quickly this was going to happen, and there was nothing they could do about it. It commonly takes just under five years for the typical battery to fail this way. Not surprisingly, that's why you'll see so many batteries come with five-year warranties. The longer the warranty they can offer, the more than can charge for that battery. Your AGM battery doesn't use that liquid electrolyte, and the lead can't really flake off like it used to. That's why we commonly see AGM batteries lasting over ten years.

I think I covered all the wondrous stuff I can think of. If you aren't having a problem, you can sleep peacefully tonight. If there is something to be concerned about, have the discussion with your mechanic about a battery maintainer, or talk with the people at any auto parts store. As I mentioned, you'll find them at Walmart too, but I doubt anyone there can answer any questions about them. I have four of them that came from Harbor Freight Tools, and one that charges five batteries at once that came from Amazon, for around $50.00.

If you can come up with more questions, I'll be back here almost every day about this time.

Thanks! They only checked my battery since I was having my multipoint inspection. Also, how many times a week would u recommend to drive to keep it fully charged? I usually make short trips and occasionally my car sits 2-3 days

Also I think you’re right it is probably 650 but the shop had listed cca rating as 640 maybe a typo so then I guess technically it was 578/650 cca

Dandy. Nothing you've mentioned suggests there is anything to worry about. From what you've told me about your mechanic, it sounds like you have a conscientious one.

The battery maintainer is a far better option than driving periodically just to keep the battery charged, unless you have someplace to go.

Sitting unused is actually less draining on the battery. My truck can sit for well over two months and still start, so that little computer memory drain isn't the main enemy. It's the really high current the starter motor draws that discharges the battery the most. After starting the engine once, I would guess it can take perhaps ten miles at highway speed to recharge the battery most of the way. A healthy starter can draw around 200 amps for up to five seconds, but during recharging, current is limited to typically less than ten amps. (Think of punching a big hole in a five-gallon bucket to drain it quickly, then you refill it with an eye dropper. You can guess which will take longer.

When the battery becomes more discharged, it will accept a higher charging current, so even though it might not reach full charge by the time you get back home, it can be charged enough that you won't notice any problem. The best thing you can do is pay attention to what your starter sounds like and how fast it cranks the engine, then observe when it seems to be cranking slower than normal. Even this simple thing can be confusing because cranking slower in cold winter temperatures can be expected. The first culprit is the battery itself. It develops its power through a chemical reaction, and those always slow down as temperature goes down. At 0 degrees, it will be able to develop roughly half the power it's rated at. The second problem is engine oil becomes thicker when it's cold, so the engine takes a lot more power to make it spin. You get half the power when you need twice the power. If it gets that cold where you are, that is when you would notice sluggish starting. If that does happen, a new battery is not the best solution. For your situation, go with the battery maintainer. If your mechanic isn't sure which type is best or will work with your vehicle, ask the people at your dealer's parts counter. Most of them also sell battery maintainers, but I suspect you would pay more there. Most of mine cost less than $20.00. They are nothing more than a very small battery charger, with circuitry built in to prevent overcharging. I found them at Harbor Freight Tools. I haven't looked at other brands, but mine have five blinking lights to show the battery's state of charge. All five stay on steady when the battery is fully charged.

Here’s the thing, we park our cars outside so in order to attach a maintainer does the hood have to stay lifted? We have had issues with palm rats in the past with our old cars, where they somehow got up into the engine bay and bit through wires and left droppings, luckily that issue is under control now and no activity has been detected after inspection, but I still worry especially with weather I. Florida dropping to 60 degrees now

Even 40 degrees doesn't mean much to a car battery, so that's not a factor. Mice and rats don't crawl in through an open hood, so open or closed doesn't matter. They jump up from underneath.

On my two main vehicles, I dropped the maintainers alongside the batteries, connected the little clips to the battery cables, then ran the cords under the hood with just a few inches hanging out in the grille or next to a headlight housing. Most of the time, if I walk by a vehicle at night, I can see the reflection of the indicator lights. If they're on solid, the battery is fully charged. If I count four or five flashes, then they start over, I know the battery is charging more and more, but has a little way to go yet. They're usually showing fully charged by the next morning.

If you use a solar-powered maintainer, you don't even open the hood to install it. They sit on the dash and plug into the cigarette lighter socket or power outlet. For those to work, the outlet has to remain live all the time, not just when the ignition switch is on. On my minivan and truck, those outlets are powered through fuses that can be installed in two different spots in their fuse boxes, depending on how you want those outlets to work. If yours are like that and need to be changed, that's a simple, one-minute job your mechanic can handle.