When a car battery dies does it give some warning that I can not see. My battery is at least 3 years old. Is it time to get a new one or do I drive until something clearly tells me it is time?
On the old-style batteries, you could test the specific gravity of the electrolyte in each cell and look for weak cells. I don’t know what you can do with a modern battery without special equipment.
Sometimes you can tell that something is wrong when you start the engine and it turns over slower than normal.
It depends.
Often, the car will “start hard” (long, slow cranking) when the battery is dying, but I’ve also seen batteries die suddenly - perfect until you come out to start the car, and then no crank, dead as a doornail.
If it’s of decent quality and you haven’t abused it (e.g. let it deeply discharge) it should be good for a couple more years at least.
Not in Arizona 
I don’t think I’ve ever had a battery last for more than 2 years out here.
After three years, from my experience if at any point I get a “hard start” or even any less responsive starter performance whatsoever, I’d be heading in to have it looked at and the charging system tested. I’ve experienced both types of battery death, with and without warning, and both stink, but the “surprise! I ain’t going nowhere” kind is worst IMO.
Keep the terminals clean and join AAA. I took my 8-yr-old Frod Focus wagon with 54k miles to the Frod dealer where I bought it for various routine servicing, fluid changes, and a minor repair (all costing $600+) including their strict 20-point checkup.
The next morning my car would not start and I called AAA and they came and verified my observation that the battery teminals had a thick crust of white powder acid leakage and I advised that it had had Frod’s 20-point checkup yesterday. I should have had the 22-point check, I guess. The AAA guy said he’s had several instances of such occurrences with the local Frod dealer. He jumped it, let it run, and I turned it off. Tried to start it again and it would not. They jumped it again and I let it run and drove it carefully 14 miles to the Frod dealer.
They could not start it without a jump, so they replaced the battery, for $60.
It started once so I let it run a while and shut it off to retest the fix. It would not start. Back to the tech. He found a broken wire leading to the battery. They did not charge me for that fix, at least not a second time.
I have since then made a capital decision to avoid Frod country and have been taking it to other service garages. Although the local AAA garage sold gullible me a pair of Kumho tires with a “70,000-mile warranty”, a written copy of which they refused to give me. “It’s all in our computer!” I later checked Kumho’s website which advised of an 85,000-mile warranty.
Please pardon the TMI.
Really? I’m curious as to why that is. Batteries last longer than that up here, but we all buy super duty $200 ones. What does heat do to a car battery?
Heat kills batteries. Many times the damage does not show up until it gets cold out.
Charging a battery creates heat. Having a battery in the engine compartment also keeps the battery hot. If the battery gets too hot either during charging or while driving, the active material will flake off of the plates. This lowers the battery’s ability to deliver power to start the car. In cold weather is when the greatest power is needed to start the car.
A couple of exampes: 1980’s Jaguar XJ6 the battery was at the back of the engine compartment on the exhaust side of the engine. It was hotter than the hinges of hell back there. A top of the line Delco battery would last 18 months. Almost to the day.
Same year XJS, the battery was in the trunk. Batteries lasted 5+ years.
Three years? Not knowing your car, it is hard to say, but on the average I would expect your battery to make it to the 4 year mark.
You can do a reasonably easy state of charge test if you have a digital voltmeter that will give you an idea of what is going on*, or any good shop can do a battery test for you. Sears in particular does a very comprehensive test on a vehicle’s electrical system. I don’t know if they charge for it, I have only seen it done as part of a battery warranty claim.
*If you want to know how, ask.
heat causes the plates to warp. As the plates warp, the active material flakes off and that part of the capacity is lost forever. If the battery gets too hot, the plates can warp to the extent that they touch and the battery shorts out internally.
Plus in a hot climate, the water in the electrolyte evaporates. If you have a sealed battery this is bad.
Cold strains batteries, heat kills them.
Start worrying around 5 years. Until then just keep driving and keep a set of jumpers in the trunk. If a battery is on the edge of failure it’s ability hold a charge falls off a cliff. Decent batteries from Walmart cost 70 installed. The dealership wanted 140. for the same thing.
You should buy the battery for the temperature conditions. One built for high cold cranking amps is not going to last in Texas. One made for warmer temperatures is not going to last starting in winter in Wisconsin. The way to test a battery properly is with a hydrometer hat floats balls in the acid to check specific gravity. The best way you can test if the cell covers can’t be removed is by a digital volt meter.
So close yet so not right.
You are correct that a battery built for high temp will not produce as many CCA as one built for a cold market. This does not alter the fact that heat kills batteries. The hotter it is (both ambient, and underhood) the shorter the batteries life.
Other than that…
A hydrometer that uses floating balls is a shot in the dark at best. If you are going to spend the money on a hydrometer buy a real one and read the actual specific gravity.
A digital voltmeter will tell you the batteries state of charge, which in the absence of more sophisticated testing methods will give you a good indication of what is going on, but it is hardly the best way.
There are electronic testers that will render an answer in about 20 seconds concerning the actual condition of the battery as well as its state of charge. This superior to a DMM. This type of tester measures conductance. Picture
The gold standard of battery testing is still the variable load carbon pile tester like a VAT 40 which does the equivalent of an EKG stress test on a battery. I have seen batteries pass a state of charge test, yet fail a load test on VAT.
I have a 2000 Lincoln Town car. It has 53,000 miles on it. That may mean something. Mostly short trips around town. It also has a lot of toys draining it.
My theory is a new car with a bad battery or bad tires is a paperweight. It is useless. But I am getting feelings .
One of my colleagues (in Nebraska) suggests that his customers replace batteries when they’re three years old as preventive maintenance. A number of other colleagues give him grief over this, as most of those batteries would still function for another year or two. But some batteries do fail prematurely, and many of his customers are happy to follow his advice because they would rather pay a little extra (probably comes to $10-20 a year) to be virtually assured of not having a battery failure. It comes down to which is more important to you, the money or the peace of mind.
My wife is the opposite of me on cars. I go for prevention. On her car every repair includes a towing charge. If it goes it is fine. If it gets back ,better. But don’t think ahead.
When my battery died about six months ago(2003 Camry, possibly original battery), I went through the agony of finding out whether I could jump it, recharge it, etc. I couldn’t. It was history. Went to Autozone, bought a new one, put in in, life goes on. But…
I remember Googling to find out about which battery I would need, which one was better, etc. Anal about this.
I remember finding some authoratative sounding postings to boards(sorry–can’t find them tonight) which said two things that I found interesting. I think I’m telling you correctly what I remember.
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In the US, there are only two companies who currently make auto batteries. They make batteries for many corporations who then brand them with their own names. But they’re the same battery.
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Years ago, batteries died by stages. When your battery wouldn’t start, it was not unreasonable to jump it, and keep on going for weeks/months/etc. Not so today. When today’s battery dies, assuming it died for reasons that don’t involve “I left my lights on overnight” stupidity, it’s dead. It’s cooked. That’s the way they work today. So, if you got your 3-5 year’s worth of use, you got what you paid for. I’m of the opinion that after 3-4 years, just replace you battery. At $20-25/year, convenience has to come into play. Not having it start one moring/night, etc, might cost you more that you lost in replacing it a year early.
If anyone can comment on my comment about today’s batteries dying suddenly, without warning, as opposed ot how they used to act, I’d appreciate it.
That might be a waste of money and resources. I bought my current car in 1999 and it still has the original battery.