Bad Car Battery?

j0nathon2

My car's battery is just 2 years old.

Over the last 2 months I've had 2 or 3 occasions where when turning on the ignition it's made a clicking type sound before finally doing it's normal thing and starting. Yesterday it never started, it just sort of clicked. I have had a dead/flat battery before and it wasn't exactly the same clicking sound but it's hard to explain.

Anyway, I have taken out the battery and put it on charge, it was approx 50% charged according to the charger, and within only 2 hours it's now showing as 100%!

Surely it should take more than two hours? If the battery was bad, would it show as 100% anyway, or how does it now how much charge is actually in it? The battery is maintenance free and it has no LED to indicate health.

If you conclude the battery is bad, what should one be paying for a new one (063 is the code on it); Halfords for instance want £59.99 for their own brand (HB063) with 3 year guarantee?

Stooby2

First off, check the battery connections (leads) - make sure they are good and shiny on the inside of the clamp. Give them a clean with sandpaper if they're not. Likewise for the battery terminals. The symptoms you describe suggest a dirty / poor connection.

Otherwise, spend a few quid and get a multimeter and Google "how to test a battery and charging system" and follow the instructions.

Weird_Nev

Sounds more like a starter motor relay or possibly something inhibiting the starter, like an immobiliser system.

Bad batterys usually turn the engine over onece or twice before failing to turn it over again, and the engine doesn't start. Nothing at all and a *click* points to something else electrical. A bad battery would fail to start the engine, but would normally at least turn it over.


As for chargers estimates of battery condition? They'll be pure guesswork.

forgotmyname

Leave your headlights on for 15 minutes. If the car starts the battery is probably good enough for a while yet.

If it doesnt start the car then its lost its capacity. That could be why it charged quickly.
Or the charger says anything below 12.6 is half charged when in reality it maybe almost full anyway.

I have a CTEK charger and it does the same. Unless the battery is at full voltage it shows the half charged LED.

j0nathon2

Thanks all.

I put the battery back in the car after 2 hours on the charger. It showed 100%.

The connections on the battery and in the car looked fine.

It started it fine, first time, no problems. Will try it again tomorrow morning.

pogofish

I agree that it could be equally to likely to be the starter relay or the starter itself.

IME, relays are particularly prone to giving-up the ghost first thing on a cold winter morning and as they don't cost a great deal from auto electricians, I'd try swapping one over to see it that helps - and if its not, then you have a spare in the glovebox for when it does finally kark!

j0nathon2

Thanks all.

Just to let you know the battery was at fault and not holding a charge. It would start fine after a charge, but leave it overnight and it wouldn't start in the cold morning.

Bought a new battery for £35 from Euro Car Parts and had no problems.

Strider590

j0nathon2 wrote: »

I have taken out the battery and put it on charge, it was approx 50% charged according to the charger, and within only 2 hours it's now showing as 100%!

Surely it should take more than two hours? If the battery was bad

That's exactly the symptom of a battery that has reduced capacity due to sulfation.
Sulfation occurs when the battery is less than 100% charged, which means it's always happening, the more the lower the battery is allowed to discharge, the quicker the battery will suffer damage.

It's like having a 4 litre bucket of water, 3/4 filled with rocks, it looks like 4 litres, but actually you've only got 1 litre of water in it.

Such a battery will charge quickly, but will lose it's charge quickly too, because it's discharge will be proportionally higher than before it's capacity was reduced.

Let's say it's original capacity was 60Ah, it's actuall capacity is now 20Ah, the battery will now discharge 3 times faster than it did new.
Not only this, but the car alarm will sense the battery voltage change over night and MIGHT start going nuts, which means you'll probably have a 100% discharged battery by the next morning. Allowing a car battery to drop to 0% charge (even for a few hours) WILL reduce it's service life by several years, if not damage it completely beyond repair.

j0nathon2

Strider590 wrote: »

Let's say it's original capacity was 60Ah, it's actuall capacity is now 20Ah, the battery will now discharge 3 times faster than it did new.
Not only this, but the car alarm will sense the battery voltage change over night and MIGHT start going nuts, which means you'll probably have a 100% discharged battery by the next morning. Allowing a car battery to drop to 0% charge (even for a few hours) WILL reduce it's service life by several years, if not damage it completely beyond repair.

Until last Friday night/ Saturday morning it hadn't ever been allowed to discharge to 0. Not sure my car has an alarm.