How long should a car battery last?

Strider590

derrick wrote: »

I know what you are saying, but if I leave it on a timer for 1 hour per week, the charger won't be live for the other 167 hours.

.

No, but there could be a leakage current that would cause the battery to discharge via the charger. They're not designed to be left connected.

Stoke wrote: »

Just letting you know, I successfully recovered an Exide battery that had been fully discharged for over 2 weeks.

Garbage battery pal. Sorry.

I recovered one (a Numax type 015) that was over 8 years old (but had only been used to start a car once) and had been flat for nearly a month, I topped it up with distilled water, charged it and it worked for about two weeks before it had to be replaced.

forgotmyname

derrick wrote: »

Video of battery charging at 1010 a.m. this morning:




Battery @ 12.5v before starting, this was after it had been disconnected for 1 week with a constant reading of 12.9v. (More info in OP.).

Went down to 11v whilst starting and was charging at 14.4v at cold, brought up to normal temp still charging at 14.4v.

Turned on rear demister, 4 speed fan and full beam headlights, (2 minutes 55 secs into video), charging at 13.6v, increased revs, charging @ 14.3v.

Engine off battery settled to 13v.


The above suggests to me the alternator is OK.

.

Thats not a proper test.

13.6v at idle and 14.3v with raised revs shows its not doing its job as efficiently as it should.

derrick

derrick wrote: »

Battery @ 12.5v before starting, this was after it had been disconnected for 1 week with a constant reading of 12.9v. (More info in OP.).

Went down to 11v whilst starting and was charging at 14.4v at cold, brought up to normal temp still charging at 14.4v.

Turned on rear demister, 4 speed fan and full beam headlights, (2 minutes 55 secs into video), charging at 13.6v, increased revs, charging @ 14.3v.

Engine off battery settled to 13v.


The above suggests to me the alternator is OK..

forgotmyname wrote: »

Thats not a proper test.

13.6v at idle and 14.3v with raised revs shows its not doing its job as efficiently as it should.

It is charging at 14.4v at idle, it only drops to 13.6 when accessories are turned on, it then increases back to 14.3 when the revs are increased as when actually driving the car, not likely, (or for a long time), that all those accessories would be on at idle.


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dlm

Firstly, before all the armchair experts start spouting - i'm a auto electrician (amoungst other things)

Battery brand is BS of the highest order. Around 90% of brands are supplied by the same factory in China. The remaining brands - of which there are 3 or 4 own their own factories. Varta for example build Bosch in Germany, Banner in Spain, and so on. Many other brands including Duracell, are all Asian.

Warranty on all batteries are also BS - Why? Well, it depends on your supplier if they will cover the cost - but the manufacturer certainly won't! I can show you a photo of a Bosch battery which failed 18 months old and even has a sticker on the battery proclaiming '5 YEAR GUARANTEE' .....Bosch stated (I received emails stating such from Bosch UK) the guarantee is 12 months from CONSTRUCTION at factory in Germany. With warehousing in Germaany, shipping, warehousing, distribution, and waiting at supplier until sold - the 12 month Bosch DO give is long gone!

If leaving a vehicle for long periods, it is recommended that you buy a battery CONDITIONER -NOT a charger, they are different things. A conditioner will charge, then discharge, and pulse in cycles to keep the plates clean of fur, and to keep the battery cycling between charge and discharge as it would if it was being used. Anything else may overcharge, overheat or otherwise damage the battery long term.

Alternators will charge properly at 14.5v optimum. Anything less need monitoring as it MAY be a sign of an alternator STARTING to fail. Alts will become erractic as the brushes start to fail, charge rate will change between 14.5, 14.2, 13 even and go back up again....in some cases to well over 14.5, This is early warning of a faulty Alt that will eventually cook the battery by overcharging.

A battery is flat at 11.5v, drop below this and many regular chargers will not charge properly, espsecially AGM and Gel batteries, In this case, a conditioner or second battery is required to fool the charger into thinking the battery is holding 12v so that it will charge the battery.

A battery holding 13.5v may still be tired, as this (as in the OP's case) is the SURFACE charge. That is what it holds on the face of things - what you need to start your car is amps (CCA) Lets say your battery is 800 CCA, fully charged but appears flat and dies immediately you sttempt to start. This is the 'DEEP' cycle which has failed. It may only knock out 400CCA instead of 800. So although on the surface it seems charged, it may not be healthy enough to start your car. Some modern cars require a fully charged battery to open the injectors etc, otherwise they crank and not start.

So to recap.

Forget brands, save £100's and buy a cheaper battery with a 1 year warranty statuatory as that is all the expensive brands will be anyway. In fact, one of the most expensive brands at over £300 only has a 2 year lifespan, 1 year warranty.

If leaving for any length of time, use a battery maintenance/conditioner and keep this plugged in. Make sure it has pulse function as some cheaper ones don't. These are not expensive, Aldi do one for £14.

Therefore, to the OP original question; Batteries will last AT LEAST a year. The rest depends on alternator condition and use of the vehicle. Yes, leaving it would have an impact. moreso during cold spells if no conditioner attached. Buy a cheap replacement, and monitor you alternator. If it fluctuates, replace the alt or brushes/charge relay.

Stoke

dlm wrote: »

Firstly, before all the armchair experts start spouting - i'm a auto electrician (amoungst other things)

Battery brand is BS of the highest order. Around 90% of brands are supplied by the same factory in China. The remaining brands - of which there are 3 or 4 own their own factories. Varta for example build Bosch in Germany, Banner in Spain, and so on. Many other brands including Duracell, are all Asian.

Warranty on all batteries are also BS - Why? Well, it depends on your supplier if they will cover the cost - but the manufacturer certainly won't! I can show you a photo of a Bosch battery which failed 18 months old and even has a sticker on the battery proclaiming '5 YEAR GUARANTEE' .....Bosch stated (I received emails stating such from Bosch UK) the guarantee is 12 months from CONSTRUCTION at factory in Germany. With warehousing in Germaany, shipping, warehousing, distribution, and waiting at supplier until sold - the 12 month Bosch DO give is long gone!

If leaving a vehicle for long periods, it is recommended that you buy a battery CONDITIONER -NOT a charger, they are different things. A conditioner will charge, then discharge, and pulse in cycles to keep the plates clean of fur, and to keep the battery cycling between charge and discharge as it would if it was being used. Anything else may overcharge, overheat or otherwise damage the battery long term.

Alternators will charge properly at 14.5v optimum. Anything less need monitoring as it MAY be a sign of an alternator STARTING to fail. Alts will become erractic as the brushes start to fail, charge rate will change between 14.5, 14.2, 13 even and go back up again....in some cases to well over 14.5, This is early warning of a faulty Alt that will eventually cook the battery by overcharging.

A battery is flat at 11.5v, drop below this and many regular chargers will not charge properly, espsecially AGM and Gel batteries, In this case, a conditioner or second battery is required to fool the charger into thinking the battery is holding 12v so that it will charge the battery.

A battery holding 13.5v may still be tired, as this (as in the OP's case) is the SURFACE charge. That is what it holds on the face of things - what you need to start your car is amps (CCA) Lets say your battery is 800 CCA, fully charged but appears flat and dies immediately you sttempt to start. This is the 'DEEP' cycle which has failed. It may only knock out 400CCA instead of 800. So although on the surface it seems charged, it may not be healthy enough to start your car. Some modern cars require a fully charged battery to open the injectors etc, otherwise they crank and not start.

So to recap.

Forget brands, save £100's and buy a cheaper battery with a 1 year warranty statuatory as that is all the expensive brands will be anyway. In fact, one of the most expensive brands at over £300 only has a 2 year lifespan, 1 year warranty.

If leaving for any length of time, use a battery maintenance/conditioner and keep this plugged in. Make sure it has pulse function as some cheaper ones don't. These are not expensive, Aldi do one for £14.

Therefore, to the OP original question; Batteries will last AT LEAST a year. The rest depends on alternator condition and use of the vehicle. Yes, leaving it would have an impact. moreso during cold spells if no conditioner attached. Buy a cheap replacement, and monitor you alternator. If it fluctuates, replace the alt or brushes/charge relay.

Auto electrician or not, personal experience suggests you're talking crap.

forgotmyname

derrick wrote: »

It is charging at 14.4v at idle, it only drops to 13.6 when accessories are turned on, it then increases back to 14.3 when the revs are increased as when actually driving the car, not likely, (or for a long time), that all those accessories would be on at idle.


.

Wrong again. Voltage dropping when accessories are switched on = something needs looking at.

Unless your accessories = powering your entire house from it.

I have a heated windscreen and rear window that automatically switches on if its below 5 degrees C. The windscreen takes almost 60 Amps, the rear window another 15amps + the heater blower and the stereo and the lights etc.. and all this with the engines glowplugs helping to warm it which is another 60 AMPS. Does not drop below 14.4 volts.

Yours drops to 13.6 with a small percentage of this load.

arcon5

A battery is flat at 12.2v

You sure your an auto electrician?

derrick

forgotmyname wrote: »

Wrong again. Voltage dropping when accessories are switched on = something needs looking at.

Unless your accessories = powering your entire house from it.

I have a heated windscreen and rear window that automatically switches on if its below 5 degrees C. The windscreen takes almost 60 Amps, the rear window another 15amps + the heater blower and the stereo and the lights etc.. and all this with the engines glowplugs helping to warm it which is another 60 AMPS. Does not drop below 14.4 volts.

Yours drops to 13.6 with a small percentage of this load.

All that whilst idling?

Or whilst driving? Which if yes is what mine does!

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BeenThroughItAll

derrick wrote: »

All that whilst idling?

Or whilst driving? Which if yes is what mine does!

.

As has already been said about a million times. Your alternator is not working properly. If it can't maintain 14+V, even at idle with electrical accessories turned on, then it isn't working properly. Remember dynamos, and how the lights would dim on older cars and brighten up when they were revved? That's the way your alternator is behaving, and it IS NOT RIGHT.

forgotmyname

derrick wrote: »

All that whilst idling?

Or whilst driving? Which if yes is what mine does!

.

At idle from a cold start, the instant it starts my heated front and rear screen and blower automatically switch on to clear the screens rapidly.

It never drops below 14.4v.

Do you know why it never drops below 14.4v? Because mine works.