Car battery cold charging amps (CCA) rating question

[Leo Enticknap]

My car (a 2018 Honda HR-V) and my wife's (a 2012 Honda Civic) both use the same form factor of battery (51R), but a different CCA rating. My HR-V's OEM battery is rated at 410 CCAs, but the Civic's is 500.

Both batteries are approaching two years old. Our car batteries have traditionally died at between 2-3 years. Therefore, I'd like to buy a battery to keep in the garage, that I can swap into either car immediately when its battery starts to show symptoms of terminal decline. I check both with a tester monthly, and top them up with a 2 amp trickle charger (just to prove what a sad, middle class, middle aged suburbanite I am, this is my first Saturday evening of the month ritual!). My wife's Civic usually needs serious charging, because almost all her driving is 2-3 miles from a cold start. Less so me, because I often do 200 miles a day on service call drives.

Here is my question: if I buy a 500 CCA spare, could I damage anything in the HR-V if it ends up being installed in it? I'm guessing that the alternator will just never charge it completely, but otherwise no problem. But just in case it's a bad idea to install a battery with a greater CCA capacity than the starter motor needs for some reason I don't realize (stress on the alternator while driving, maybe?), I thought that it's a question worth asking. Thanks in advance.

[Dave Macaulay]

Not a problem. The alternator will charge it fine. CCA is an odd rating - the maximum amperage possible at some low temperature and some cutoff voltage: I don't know either but you can look up the rating method. In California I doubt that cold cranking is a major concern. Here in Toronto and further North it is, a battery that spins the motor in summer shows its CCA (and its condition...) trying to start the motor in winter.
Generally higher CCA is better (and more expensive but with a better warranty), but there's no point in putting a humongous diesel truck battery in a Fiat 500 unless you want to leave it off with the lights on for a few weeks.
Any 51R battery will be OK. The higher CCA ones will weigh more than lower rated but that is likely not a concern?

[Frank Cox]

It's my understanding that a battery creates power through a chemical reaction. So wouldn't die just from sitting around as the chemicals age? I wonder how wise it is to keep a spare for long periods; won't it age out sitting on the shelf?

[Steve Guttag]

Lead Acid batteries tend to fail from cycling more than sitting. Most car batteries (standard ones) are VERY much designed to stay a full charge. Their plates are constructed like sponges and the act of discharging will clog them up so they they cease to function or function fully after just a few cycles like that. They are built to get the car started, primarily. You want to keep them topped off at all times. If you are looking for a lead-acid that can withstand many full cycles...look for a marine type deep-cycle/rv type battery. They use a more traditional metal plate infrastructure so there is nothing to really clog. They are not good at starting cars but they are good at a long-slow-dissipation and repeating the cycle.

I would think that a typical car battery, with a trickle charger on it will stay good on the shelf for the full 5-6 years of the battery's life and definitely not be any worse for wear than in an actual car. Discharge is its enemy.

[Paul Finn]

Frank makes a good point. Auto batteries need some "cycle" activity. I had a spare almost new car battery and religiously trickle (top-off) charged it every three months It was stored in a heated room.. After about three years, it would neither accept charging nor deliver power. I have had many times, over six plus years of faultless service from OEM new vehicle batteries through Michigan winters with most trips longer than twenty miles. Replacement batteries don't ever seem to be as good as the OEMs. In Leo's situation, it may be better to periodically swap the spare into his road trip car to insure having a good spare available.

[Mike Blakesley]

We sell batteries here at the store (DieHard) and I can tell you from years of experience that they are pretty much a random animal. A person can buy "x" battery and get 7 years out of it, and replace it with the exact same battery and it will last 2 years. It's kind of infuriating for us sales guys. But keeping a battery charged is definitely the way to go.

Everything Steve wrote above is accurate.

The CCA (cold cranking amp) rating is measured at zero degrees F, and the CA (cranking amp) rating is measured at 32 degrees F. The most recent batteries we're getting are only labeled with the CCA rating which is a better indicator of a battery's capacity under more possible weather conditions. If you tend to leave a vehicle sitting for long periods, or live in a cold climate, a higher number will be the better choice, plus it usually has a better (longer) warranty.

[Leo Enticknap]

Thanks folks. As I say, all our previous batteries have lasted between 2-3 years, so one I buy now is not going to sit around on the shelf for very long. If any of the auto parts stores around here are doing a Labor Day special, I think I'll snag a 500.

[Marcel Birgelen]

It somehow also seems to depend on the car. I've had cars that could run with a single battery for years on end, even after pretty harsh winters for the region. On the other hand, my wife's previous car seemed to eat them for breakfast. Getting more than a year and a half out of it, wasn't possible. I guess the recommended type was somehow underspeced for the car, but a larger battery didn't fit.

About a year and a half ago, I encountered the possible solution: A Lithium ion based battery. The thing was much smaller than the battery it replaced, yet outspecced the thing it replaced on paper. I don't remember any specific numbers. Case in point: The Li-ion battery was dead the first time temperatures hit below freezing. Maybe I had a faulty one, but it didn't inspire much confidence in the readiness of Li-ion batteries to replace our traditional 12V lead batteries.

[Frank Angel]

Just coincidentally, Just three days ago, I came to my car and the battery was totally dead. Evidently I had inadvertently left the Hazards on and since we are covid prisoners, we hadn't been down to the car in five or six days (not sure...my brain doesn't compute time anymore). I mean, it was dead beyond even a glimmer of any power. And as Steve says, the worst thing for a lead-acid battery is a full discharge. I have had this experience a number of time in my younger years when cars were stupid and no more complicated than having a few ON and OFF switches and maybe some relays and a sensor here and there. They required you not forget to turn off the headlights, especially during the daytime. And of course, AI never forgets, but we are not AI but HI and we do forget on occasion. And each time I found my battery dead, it would prompt a headlong launch into my favorite rant about why on earth would anyone design a car's electrical system that would allow lights to stay on and drain the battery when the motor was shut off? And as the default. no less? OK, yes, if you think there might be the RAREST of occasions where the owner might want the lights to stay on after the motor was shut off, i.e., discharging the battery, then make it a separate forced decision by some sort of additional switch. For example, you have to reach under the dash to throw an additional switch to keep the headlights on after the motor is off. But to have it possible to just accidentally leave the lights on when rigging them to go off with the ignition switch is so EASY, doing it they way it's been done since I was a boy, IMHO, is totally irrational, ESPECIALLY given the fact that the we know the designers KNEW it was very problematic because they designed a warning signal to go off to alert the drive. Huh? Why did they set it up like that in the first place and when the first guy said, "Hey, you know it's real easy for the driver to forget that the lights are on and that will kill the battery," what force in his head made him follow that with, maybe we should put a warning noise? instead of just eliminating the potential problem altogether -- just put the damn lights on the ignition switch!

If anyone can come up what they thought the rationale was for rigging the headlights that way, i.e., so they would just stay on until the battery was toast, I'd love to hear it.

After three times being stung by a dead battery because of not realizing the lights were still on, I installed a simple relay to kill the headlights when the ignition was OFF. That was decades ago. Now of course everything is automatic and I guess SOMEone in R&D hit upon this great idea to NOT let the headlight destroy the battery. Except now I just discovered that the computer will not turn off the Hazard lights, and rightfully so. I will just have to see how much damage was done to the battery being so fully discharged for days.

But now I have a different rant -- with these sophisticated car computers, how come the computer can't sense when the Hazard lights have drained the battery to a level that is approaching its inability to start the car, and then just shut off the Hazard lights?. Huh? How come it can't do that, scientist?

[Mike Blakesley]

I'm no scientist but I think I can come up with a couple of common sense answers.

For the hazard lights -- I suppose the thinking is, you wouldn't turn on your hazard lights unless your vehicle was causing a hazard of some kind. So if you're sitting there blinking on a busy highway and then all of a sudden your hazards shut off (when they still might have had a few hours of life left in them), then your vehicle would become much MORE of a hazard. So my guess is they design them to keep blinking as long as possible.

As for the headlights....you have to remember that the earliest cars didn't even HAVE headlights. So when they were added, they probably didn't think far enough into the future to design some sort of timer or alarm to shut them off or warn you that you'd left them on. Same reason the earliest cars with seatbelts didn't beep at you to remind you to put the belts on, or the earliest cars didn't have a red light that came on if you were low on oil.... you had to check it yourself.

The thing I don't understand is, why can the car talk to you about what radio station you want, or what song you want to hear, or what directions you need, but it can't say a simple phrase like "Fasten your seatbelt please" or "Your left tail-light is out." For THOSE things you have to decipher beeps and dings and stuff.

[Marcel Birgelen]

The thing I don't understand is, why can the car talk to you about what radio station you want, or what song you want to hear, or what directions you need, but it can't say a simple phrase like "Fasten your seatbelt please" or "Your left tail-light is out." For THOSE things you have to decipher beeps and dings and stuff.

Most modern cars will have some kind of log you can scroll through with messages of things that need attention. This increasingly also includes dying batteries, although the art of detecting premature battery failure is seemingly still somewhat out there.

There also is a difference between danger messages that need DIRECT attention and warning messages about stuff that won't cause havoc in the next few seconds if not resolved immediately. So, if my tail-light goes out, I personally would prefer a slight beep and some short message on screen that I can get the details of, once I safely parked the car. On the other hand, if I'm about to crash into the car in front of me, because he/she decided it's time to hit the brakes with full force and I wasn't paying attention (maybe because of that unexplained error message that just hit me.), I'd rather prefer the car to scream at me as loud as possible.

[Leo Enticknap]

As for the headlights....you have to remember that the earliest cars didn't even HAVE headlights.

And furthermore, the first headlights were not electrically powered. I read this book back in the Spring (Kindle was doing a $1.99 special on it). It explained that one of the earliest promoters of and investors in the Lincoln Highway, Carl G. Fisher, made his fortune by investing in a manufacturer of acetylene gas headlamps, who persuaded many of the emerging automakers to install them as standard equipment. Electric headlamps did not become commonplace until the late teens/early 20s. Fisher lost most of his fortune by sinking it into Florida real estate shortly before the Wall Street Crash, but not before he had been instrumental in getting the country's first coast-to-coast paved road built.

As for battery life, I don't know why ours have consistently lasted for 2-3 years and no longer: all I know is that they have. I don't think that the usage pattern is behind it: I do 35-40k miles a year mainly on long haul freeway runs, whereas my wife does around 6-7k a year, mainly local. Both our batteries have around the same lifespan. I think the extreme climate cycles in California (from a predicted 115 this coming weekend, to overnight lows in the 20s in winter) might have something to do with it.

[Marcel Birgelen]

As for battery life, I don't know why ours have consistently lasted for 2-3 years and no longer: all I know is that they have. I don't think that the usage pattern is behind it: I do 35-40k miles a year mainly on long haul freeway runs, whereas my wife does around 6-7k a year, mainly local. Both our batteries have around the same lifespan. I think the extreme climate cycles in California (from a predicted 115 this coming weekend, to overnight lows in the 20s in winter) might have something to do with it.

What I know from my days working in and around datacenters, is that once we installed air-conditioning in the battery rooms the lead batteries (mostly of the traditional, plate-style types), they essentially seemed to last "forever", whereas before, they were replaced every two or so years. So, a stable climate, as in a stable temperature most definitely has a big impact on the longevity of lead-style batteries and probably most types of batteries out there.

Electric cars employ all kinds of wizardry to limit the amount of charging and discharging in extreme weather conditions, in order to prolong the lifetime of the batteries. Those are generally some kind of Lithium ion batteries, but those also seem to heavily degrade under adverse climate conditions, especially when placed under stress under those conditions.

[Lyle Romer]

The thing I don't understand is, why can the car talk to you about what radio station you want, or what song you want to hear, or what directions you need, but it can't say a simple phrase like "Fasten your seatbelt please" or "Your left tail-light is out." For THOSE things you have to decipher beeps and dings and stuff.

Probably so that the same safety type alerts can be used across all trim levels when they get DOT approval (or however they get certified) to sell a model. For example, I don't believe the XL trim level of the F-150 has any voice interface but the higher trim levels do. It would cost Ford money to make a different system (and get it approved) for the various trim levels.

[Buck Wilson]

I think the extreme climate cycles in California (from a predicted 115 this coming weekend, to overnight lows in the 20s in winter) might have something to do with it.

Yes, absolutely. Heat kills batteries, cold weather merely shows the symptoms of degraded performance sooner.