After helping someone push their car into a dark, cold lay-by today due to a failed battery cell I had some thoughts and questions which I will put to you.

Why do motorists wait until the battery has actually failed before changing it? Would it be a good idea to change it after say 4 years regardless to prevent issues when you are out with the car?

The handbook says to take your car into the dealer to have the battery changed - why is this? Would the ECU lose data (Fabia) if power is removed?

What signs does a failing battery give (apart from the obvious not starting)?

Lastly, I note in Halfords that 4 year calcium batteries for the 1.9 TDI Fabia are only £98. To me this is good value - a stonking great battery with a 4 year warranty for less than the price of a meal out for 4.

Yor thoughts on car batteries are welcome.

TH

When i change my car battery's, i always attach the Battery charger to the Neg & Pos leads & then remove the battery/replace. This just saves all the hassle of Alarms, Stereo Codes, keycodes Etc Etc..

Just bought a heavy Duty Banner Power Bull battery for my Vrs with a 4 Year Warranty for £59 from my local Motor factors

Cheers

Dean

What signs does a failing battery give (apart from the obvious not starting)?

If a battery is slowly losing its capacity to hold a charge it will generally start to crank the engine slower on startup (but this is when it is on its last legs, and about to leave you stranded). A load test gives an indication of what condition a battery is in.

If it has a dead short or has a mechanical internal failure it can just suddenly go dead (no power at all). This can happen when you are driving along and the car may continue to run on the alternator alone, you may not know there is a problem until you go to restart.

Lots of batteries are replaced when they are perfectly servicable, while the real problem is with the alternator/voltage regulator or the starter motor.

:iagree: The real mystery is why people blame a weak alternator, wornout starter bushes or a duff solonoid on the battery.

Would it be a good idea to change it after say 4 years regardless to prevent issues when you are out with the car?

Only if you have money to burn, SHMBO's old Fiesta was on its original battery when i changed it - when it was 12 years old!

OK that is not the norm i know but it does show they can go on for MUCH longer than 4 years.

I've had a couple of batteries fail suddenly with no indication of a problem beforehand. This was in different cars as well, one petrol, one diesel.

When i change my car battery's, i always attach the Battery charger to the Neg & Pos leads & then remove the battery/replace. This just saves all the hassle of Alarms, Stereo Codes, keycodes Etc Etc..

Dean

Dean,

Just a quick note, its not a good idea to put a charger across the terminals as you suggest, as a charger can put up to 20 Volts and without the battery as a capacitor

you could take out some sensitive equipment.

What you need is a regulated power supply rated at 13.8 Volt or less (12 Volts)

Radiotwo

Lastly, I note in Halfords that 4 year calcium batteries for the 1.9 TDI Fabia are only £98. To me this is good value - a stonking great battery with a 4 year warranty for less than the price of a meal out for 4.

I believe the warranties only usually give some money off a new battery (rather than replacing the battery outright). You will find out that £98 battery will be much much cheaper with a Halfords Trade card. See http://briskoda.net/general-car-chat/got-me-halfords-trade-card-d/103193/

thing is the markup on batteries is ridiculous, but i do think it should be part of the service schedule.

Dean,

Just a quick note, its not a good idea to put a charger across the terminals as you suggest, as a charger can put up to 20 Volts and without the battery as a capacitor

you could take out some sensitive equipment.

What you need is a regulated power supply rated at 13.8 Volt or less (12 Volts)

Radiotwo

Forgot to mention, it is a regulated charger & pushes out 12.8 Volts

But a good point to mention

Cheers

Dean

Going off of past experiences, usually with the engine off the headunit use to last no longer than 10mins without the engine running.

And also, my Mk4 1.8 Astra Hatch was really tempremental doing hill starts or holding it on the clutch.

You couldnt get the revs to stay where you wanted :S, as soon as i changed the battery all was fine.

Forgot to mention, it is a regulated charger & pushes out 12.8 Volts

But a good point to mention

Cheers

Dean

Dean

If it is a regulated supply at 12.5 Volts then it will be no good for charging, you need at least 13.9 Volts and 14.5 better, but at that voltage you will have to watch how long it is

left on, as it will boil the battery

Radiotwo

you will not Boil the Battery when voltages between 13.9 and 14.5 are applied to it all the time. When a 12 volt battery becomes fully charged , its terminal voltage will read 14.5 volts, and the current supplied by the charger will drop to a low save level ,say 0.5 amp ( even though when first connected the current was say 6 amps).

This is what automatic chargers which can be left connected for a long time rely on.

To sum up any charger which does not give more than 14.5 volt out ie an automatic one, will not damage the battery. Batteries get damaged when a high current charger (above 10amps) type is connected for a long time ,say over 24 hours,if the battery is a non sealed type the water in the electolyte changes to oxygen because of the overcharge.The average flat battery can be recharged at 4 to 6 amps in a period of 12 hours. A good way to check whilst charging is to feel the side of the battery ,it will feel slightly warm when fully charged. The only time a battery will 'Boil' is if a car alternator becomes faulty,and gives its maximum current (between 60 and 100 amps ) out all the time when the car is being driven,or the battery is connected to one of those Garage High rate charger which is faulty or ,on the wrong setting.

Edited 24 January, 200917 yr by AndyPandy