How long should a car battery last

I realise this is a ' how long is a piece of string? ' question, but what sort of lifespan am I looking at?

It's 12v 65Ah, capable of 720A burst. Don't quote me, that's what the label reads.

Been on my diesel car for 9 years now, with no starting problems whatsoever.

I know these batteries don't like to be deeply discharged, so I pretty much start the car and run only neccessary electrical gadgets. Never use stuff without engine running.

Then my journey is sufficiently long enough to fully charge it again.

Can these batteries go on for decades if looked after, or should I release the moths from my wallet and buy a new one?

What kills car batteries is leaving your lights or radio on without realising it and running the battery flat, or anything else that causes the battery to go down when your not using the car. The longer you leave them flat, the more it kills them. Other than that, they can last a very long time and any deterioraion will be gradual. You'll know when its ready for changing because on these very cold mornings, it'll struggle to turn the engine over. Sometimes, if you've got other problems with your ignition system, a new battery can give a little bit more oomph to overcome the problem, but it would be better to sort the ignition rather than buy a new battery,

In summary, if it aint broke, don't fix it.

Many years ago they often lasted only about 3 or 4 years for reliable cold starting in winter, but they have been continuously improving. But so much depends on usage that no general prediction can be given. My car usage over the last 20 years in retirement has been very intermittent, leaving a car for up to even three months between uses (but still starting ok), since I mostly cycled plus some motorcycling. Treated like that the batteries only lasted five years.

These days my later cars have sometimes had so much in the way of continuous running equipment discharging the battery, they have to be run at least once a month if they are to start. And this is where the car comes into battery life as well. Worst owned was a Nissan Qashqai which couldn't start after as little as 3 weeks idle in cold weather, due to the drain of the amount powered up continuously. This included the car's integral computer system and it's cabin ultrasonic alarm system, my trade contacts telling me this high standing discharge is increasingly common on today's cars. No battery life known there, I sold it at 3 years old.

That's my experience. I have a Berlingo van which will be 11 years old in March, and that is still running on the original battery. I suspect 11 years is about the limit though. Round about next November if I still have it I'll probably need to replace the battery - that'll be 11 1/2 years.

As Flecc says, crucial is the drain of any electrics. In the case of the Berlingo it appears to be as close to zero as makes no difference.

Apart from that, it doesn't get a whole lot of use. It's a company vehicle, but most of my work is in London and I invariably use public transport - it's free and usually quicker. I'm limited to what I can carry but I'm used to being selective and seldom get caught out. The van has now done almost 90,000 miles in total, but most of that would have been much longer trips where public transport would be inappropriate or not possible.

Another critical factor is that it starts instantly in any weather as soon as you turn the key. Every second the starter is in operation shortens the battery life.

Rog.

That's my experience. I have a Berlingo van which will be 11 years old in March, and that is still running on the original battery. I suspect 11 years is about the limit though. Round about next November if I still have it I'll probably need to replace the battery - that'll be 11 1/2 years.

My Peugeot 406 diesel is late 2001 and still on the original battery. I imagine it'll do this summer again and peg out in November. Or next November. Or maybe, perhaps, the November after that.

People have told me that batteries and light-bulbs could be made to last forever but the stinking capitalist system stops the production and marketing of all the good ones. Naturally, I'll believe what they say and wait patiently for the revolution.

For the meantime, I'll accept any and all tips on how to keep the Lion battery on my Cyclamatic at 80% charge, which the Battery University tells me is ideal for maximum life (up to 5 years?). A charger set to 4.05v/cell (instead of 4.20v/cell) will do that. Full charge only when planning a long trip.

 

Another critical factor is that it starts instantly in any weather as soon as you turn the key. Every second the starter is in operation shortens the battery life.

 

Rog.

My regularly used garage-kept little town car really didn't like the -8 degrees C this morning, it's customary instant start replaced by a sluggish 5 seconds of turning before bursting into life. Battery is in the middle of it's fifth winter. I'll be very surprised if it doubles that life span.

My regularly used garage-kept little town car really didn't like the -8 degrees C this morning, it's customary instant start replaced by a sluggish 5 seconds of turning before bursting into life. Battery is in the middle of it's fifth winter. I'll be very surprised if it doubles that life span.

It'll just be the oil thickening up due to the very low temperature.

Liken it to golden syrup on your pancakes. The missus keeps our syrup in the fridge, so takes an age to drop off the spoon.

I try and pre-empt a pancake feast, and remove the jar from the fridge an hour before.

Imagine your poor old starter motor trying to turn over the engine mechanicals while the oil is thick and treacley.

Puts an extra strain on the battery, which is why some cars fail to start on these cold mornings.

My regularly used garage-kept little town car really didn't like the -8 degrees C this morning, it's customary instant start replaced by a sluggish 5 seconds of turning before bursting into life. Battery is in the middle of it's fifth winter. I'll be very surprised if it doubles that life span.

I have the same problem with my Audi. The original battery was massive (100 aH?) but it drowned due to a design fault, so had to be replaced. Nobody had the big one but they all offered a smaller (80aH?) one which they swore was a suitable replacement, so I accepted what they said. Big mistake: It struggles a bit at -5 deg C, but last year at -15 it was 50/50 whether I could start, but I found that putting it on charge for 10 mins before setting off seemed to warm it up enough to start the car.

Oh I realise that Fordulike, I'm a fully qualified motor mechanic, cars and trucks, from an earlier era! I worked my way through all the vehicle types from powered bikes and motorbikes upwards. Nonetheless, the battery performance is down from last winter at it's worst, hence my prediction about the rate of decline.

I have publicly flogged myself :o

I have the same problem with my Audi. The original battery was massive (100 aH?) but it drowned due to a design fault, so had to be replaced. Nobody had the big one but they all offered a smaller (80aH?) one which they swore was a suitable replacement, so I accepted what they said. Big mistake: It struggles a bit at -5 deg C, but last year at -15 it was 50/50 whether I could start, but I found that putting it on charge for 10 mins before setting off seemed to warm it up enough to start the car.

Yes, I too like a larger battery and always replace with larger capacity than standard. That in my little town car is small, 45 Ah, but it's been ok for it's small engine for four winters. Up until last March it was always outdoors and the battery was fine during last winter's severe weather. Since March it's been in a well sheltered and dry brick-built garage, but the battery isn't doing as well, so it's obviously in decline. The garage is separate from my home with no power so top-up charge isn't convenient.