Battery drain

[elmerfud]

I have a Citroen Xsara Picasso 2 Litre HDI, I had a new battery fitted last week and before it was fitted by my trusty mechanic he tested the current was correct going back into old battery. Unfortunately after 2 days of non use, the engine just about turns over. Has anybody got a clue, or had this same problem?

[falling-out-with-my-car]

I always bench charge a brand new battery for at least a week and then twice a year spring and autum.
have you been doing short trips out with the lights on/radio on/heater on? it takes 20mins of fast running to put back
what you take out in starting.
Is your al;ternator ok-charging?
you just never know how long the person you bought it from has had it standing without a maintenance charge.
Just out of interest what size is the battery cold start amp rating? and what is the date on the battery?
presumming the battery is ok suspect the alternator, if the old battery was charging enough to start the car several times a day
it might be a dud New battery. I'd give it a three day charge and try again, meanwhile you could put a volt meter across the battery terminals with the engine running and test the alternator output which is about 14 volts.
if it is lower replace the alternator.

[Northern_Mike]

I always bench charge a brand new battery for at least a week and then twice a year spring and autum.

Might I ask why? All the ones I've bought in the last few years have had a full charge. I've not even got my battery charger out for about 7 years.

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[falling-out-with-my-car]

Wow you don't do any maintanance on your car batteries well you have been very lucky then or you have extreemly deep pockets.
I have done tha same as you and found they dont last very long esspecially when the weather gets cold
and there is more demand on the battery. in very cold weather the amps drop anyway. even on a new battery.
A new battery generally maintains 80% of its total charge capacity some are dry stored so that the plates do not corrode in storage although this practice is getting rarer of late. you should if possible check the fluid levels and give the battery a charge to get it up to full capacity, your alternator is not supposed to charge the battery but simply maintain it and if the battery is at full capacity when you nstall it the alternator should maintain it at full capacity not rthe 80% capacity it was when you bought it. just because it says Maintenance free sometimes doesnt mean dont charge it, it generally means you can't top up the fluids. How do you know they have all had a full charge? a volt meter gives voltage Not amps at full capacity which is what is required to crank the engine easily. This is difficult to measure without expensicve equipment.

at the end of the Day its really up to you Ive only ever bought one new battery in 10 years on a 1.9TD Xantia and I always put a maintenance charger on the battery if the car is not to be used for four days or more or if I am only doing short journeys less than 20 miles per day for a week. One of my neighbours charges his battery on his car every weekend because he only goes to work and back 5 miles in the dark in five days, if he ignored charging and went two weeks his battery would be dead.
some like to insulate the battery in very cold weather conditions to. I generally prefer to buy a battery that can be maintained and topped up as opposed to a maintenance free one, you can shine a torch into the vent holes to see the electrolyte levels and top up with distilled water if necessary.
This link points to some very good information about new batteries in new cars failing, diagrams and what can be done about it.

http://batteryuniversity.com/learn/arti ... es_to_fail" onclick="window.open(this.href);return false;

[Xantidote]

I generally prefer to buy a battery that can be maintained and topped up as opposed to a maintenance free one

Me too, but there's nothing to stop you prising the top off a "maintenance free" battery, although it's more fiddly

[Peter.N.]

I have never had a problem with my batteries either, unless there has been a fault on the car. The output of a modern alternator will replace the charge used by a normal cold start in a few minutes. In the days when they used dynamo's they could benefit from a charge as the output was only 19 amps, even less on the ones without regulators, so the battery was supplying some current to the lamps, wiper etc, you could always tell when they were fully charged though as the panel lights came up brighter.

The sole job of an alternator is to replace the power taken by a cold start, once the engine is running the alternator has sufficient output to supply everything - except perhaps a 2kw sound system.

The construction of a car specific battery is such that it has a very large plate surface area which will still supply enough current to start the engine when its down to 20% or less capacity and I mean by that having lost that much useable capacity due to age, it has very little reserve though and leaving the headlights on for an hour could flatten it.

If a battery needs regular charging either its on its way out, its not being charged properly or something on the car is draining it.

Peter

[Mandrake]

A new battery generally maintains 80% of its total charge capacity some are dry stored so that the plates do not corrode in storage although this practice is getting rarer of late. you should if possible check the fluid levels and give the battery a charge to get it up to full capacity, your alternator is not supposed to charge the battery but simply maintain it and if the battery is at full capacity when you nstall it the alternator should maintain it at full capacity not rthe 80% capacity it was when you bought it.

I'm afraid I can't agree with any of that. Of course the alternator is supposed to charge the battery and not just maintain it. The alternator in a car can supply 60-120 amps depending on type, which is far more than any standard mains charger. Lead acid batteries are designed to be charged by "constant voltage" chargers - as long as the charging voltage is correct (14.2v ideally, and not outside 14.0 to 14.4v) then the alternator will charge the battery to 100% capacity.

With a Lead Acid battery its the precise charging voltage that determines what percentage of its capacity it will be charged up to, with relatively small differences in voltage representing large differences in charge capacity, hence checking the charge voltage is correct within +/- 0.2v.

As for checking fluid levels - I haven't seen a non-sealed lead acid car battery for years. Yes you can still check the levels if you're determined to peel off the seals etc, but there is no reason to do this on a brand new battery IMO.

I have nothing against the idea of putting a new battery on a trickle charger for a little while before fitting it, (although I have never done so) but there's no way that it needs a week (a few hours would do) and as soon as the car is driven any distance a correctly functioning charging system will fully charge the battery.

just because it says Maintenance free sometimes doesnt mean dont charge it, it generally means you can't top up the fluids. How do you know they have all had a full charge? a volt meter gives voltage Not amps at full capacity which is what is required to crank the engine easily. This is difficult to measure without expensicve equipment.

Again - if the charging voltage is correct a new battery will just sort itself out. Put the new battery in the car, take it for a 30 minute drive and it will be charged properly.

at the end of the Day its really up to you Ive only ever bought one new battery in 10 years on a 1.9TD Xantia and I always put a maintenance charger on the battery if the car is not to be used for four days or more or if I am only doing short journeys less than 20 miles per day for a week. One of my neighbours charges his battery on his car every weekend because he only goes to work and back 5 miles in the dark in five days, if he ignored charging and went two weeks his battery would be dead.

I think I've had one battery fail on me in just over 20 years of driving, and that was a battery that was many years old in a car I'd recently bought, so for me, battery failure is just not something I've had much trouble with.

Sounds like your neighbours car's charging system isn't working properly - 5 miles is plenty of driving to replenish the charge used by starting.

I'm not proud of it as its rather wasteful, but I'm actually driving my Xantia V6 one mile each way to a train station during the week, and have been doing so for over a month - it starts perfectly on the button even at -3 degrees, gets maybe 2-3 minutes of idling while I clear the windows and another 3 minutes of driving. No problems at all with the battery because its a good battery and the charging voltage is correct.

Modern batteries are far more reliable than you give them credit for - the two main causes of battery failure is incorrect charging voltage (too low or too high) or running them flat. Once they've been run really flat unless you get them charged up ASAP (within hours) the sulphating of the plates will cause permanent damage.

I accidentally ran mine down once while I was working on the car (doing injector testing and lots of engine starts) to the point where it wouldn't operate the starter solenoid, but as soon as I realised what had happened I immediately took it out and put it on a 5 amp trickle charger for the rest of the day and night and refitted it the next day and it has been fine ever since. If I'd left it for 24 hours or more before re-charging it it might have been a different story.

[RichardW]

I think you're right Peter, Nigel is confusing alterntors with dynamos.... The one on my car can put out 150A. A cold start takes what 2 seconds at say 600A = 0.33 Ah - just 0.5% of capacity of a new battery. Not going to take long to replace that at 75A say available from the alt even with everything switched on (although admitedly, the available charging current reduces as the charge and hence volt difference comes up. I've always just bunged batteries and on and used them - never had any problems. Maybe I only get 5 years instead of 7, but I've only bought about 3 new batteries in 400k miles, so I can live with that.

[falling-out-with-my-car]

Sounds like your neighbours car's charging system isn't working properly - 5 miles is plenty of driving to replenish the charge used by starting.

thats 2.5 miles lights on at 5am heating on radio on windscreen wipers if necessary. 8 hours rest then another 2.5 miles home again in the dark heater on lights on radio on yopu get the picture? your surely not telling me the alternator can cope with charging a battery in 2.5 miles each way stop start driving?

it does say here somewhere a 30 mile drive will fully charge the battery Not 5 miles with just about every accessory running
at the same time. I appreciate there is a regulator involved but the alternator canno0t cope with it all hence why headlamps go dim when the battery starts to suffer as power is routed to keep everything else running instead of charging the battery.

charging should be at a constant speed not stop start driving either, esspecially in a petrol engined vechicle that requires the battery to be cxonnected to maintain the ignition at ldle speeds. unlike a diesel.
as I said orriginally it takes about 20 mins of constant driving to put back what the starting of the engine takes out of the battery.
On Modern vechicle with alarms rear heasted windscreens cd players and fan motors than often run continuosly a battery is under a lot of stress, some may prefer not to maintain their battery at all and good luck to them I prefer to maintain mine

Have always maintained lead acid batteries where ever possible and the statement about not seeing any not maintainence batteries for years just means you havent been looking how often do you actually look at battery design if you stick one in the car and forget about car batteries altogether. and you can easily measure the output of your alternator in amps can you?

Did anyone actually read the thread on the link I put up in tha last comment?

I am talking trickle charging here not 4amps constant more like half an amp or less.

yourI mile commute to the station in your V6 does it include radio on heater on lights on to?

I simply don't buy it if this is the case, I find prevention is always better than failure.

[Mandrake]

thats 2.5 miles lights on at 5am heating on radio on windscreen wipers if necessary. 8 hours rest then another 2.5 miles home again in the dark heater on lights on radio on yopu get the picture? your surely not telling me the alternator can cope with charging a battery in 2.5 miles each way stop start driving?

It should easily cope - its not trying to charge a flat battery, its trying to top up a battery that is still 98% charged. As RichardW said - the starter is running for what, two seconds ? In terms of amp/hours that is nothing. Battery efficiency does decrease quite a bit at high currents well beyond the amp/hour capacity of the battery so there isn't a linear relationship with the amp/hour figure, but the battery will still be fairly close to fully charged.

it does say here somewhere a 30 mile drive will fully charge the battery Not 5 miles with just about every accessory running
at the same time.

If it were really flat (to the point where it only barely started the engine) it would take maybe half an hour of driving to fully charge the battery, but not from an otherwise charged battery which has simply started the engine.

charging should be at a constant speed not stop start driving either, esspecially in a petrol engined vechicle that requires the battery to be cxonnected to maintain the ignition at ldle speeds. unlike a diesel.
as I said orriginally it takes about 20 mins of constant driving to put back what the starting of the engine takes out of the battery.

If that were true my battery would be flat now, only running for less than 5 minutes per start, 10 times a week, yet it shows no signs even of slower turn over when starting. Sometimes it doesn't even get driven on the weekend either.

Older alternators weren't able to output enough at idle to reach 14.2 volts and would often be as low as 13.8 volts until the engine revs got up over about 1500 rpm, so its true that you would never fully charge a battery while idling on an older car, but I notice that a lot of modern cars are able to reach charge voltage (albeit at reduced current) even at idle. It would take a bit longer at idle to fully charge but it would get there.

On Modern vechicle with alarms rear heasted windscreens cd players and fan motors than often run continuosly a battery is under a lot of stress, some may prefer not to maintain their battery at all and good luck to them I prefer to maintain mine

Yes but modern vehicles also have alternators that have massively more current output than those of cars 30 years ago, (look at Richards example of 150A - I bet my old GS alternator wasn't even half that) and the electronic regulators now standard are light years ahead of the horrible crude coil/contact vibrator type regulators of old. (It's so long since I've seen one I've forgotten what they're called )

So yes they need more power but they have better charging and regulation systems too.

I am talking trickle charging here not 4amps constant more like half an amp or less.

But 4 amps is a trickle charge for a 60 amp/hour battery. Anything from about 1/10th to 1/20th of the amp/hour capacity is considered a trickle charge. Half an amp on a 60 amp/hour car battery is below a trickle charge and wouldn't really do anything except prevent self discharge.

yourI mile commute to the station in your V6 does it include radio on heater on lights on to?

I simply don't buy it if this is the case, I find prevention is always better than failure.

Headlights on, rear window heater and rear mirror heaters on, heated seat on (only the passenger one works ) and cabin blower fan on full blast thawing out the windscreen. (Which draws 20 amps by itself)

Believe what you will but I have zero problems with the battery not being maintained despite the short trips and high accessory load.

[falling-out-with-my-car]

maybe in a petrol car
My neighbour has a diesel and is heating his glow plugs to as well as turnni g the engine over and running the accessories.
Mines a diesel to..
My Fathers xantia diesel VSX also needs the battery maintainning to, it to sufferws with shourt journeys esspecially as the nights get colder. he had a new battery lasdt year and yes one that you can maintain. anoither beliebver in Maintainning your lead acid batteries.

[Peter.N.]

I have been running diesels since 1959 and in the early days they were pigs to start, lorry drivers used to light fires under the engine, nowadays not only do diesels start more easily and quickly but the output of the alternator makes sure that the battery is fully charged most of the time.

I have a 406 and a C5 Hdi and they both start within a second or two using probably only 1 or 2 ah of the batteries capacity. The battery on the 406 failed recently, I don't know how old it is but it was on the car when I bought it about 4 years ago, the capacity was down to around 20ah or less, being originally 68ah, if you left the headlights on it would go completely flat in less than 2 hours, yet it still started the engine instantly when charged. I eventually killed it by leaving it on fast charge all night

Even with all the electrics on the alternator will have spare capacity, that's how they are designed and they give a large proportion of their max output a tickover speed. You can tell by listening to a car with a loose alternator belt how long it takes for the battery voltage to back come up after starting by how long it squeals which isn't long.

All the things that Nigel says apply to the cars I used to drive in my youth but they don't apply now.

Peter

[falling-out-with-my-car]

Peter,
funny that its probably when I went to college to do my Mechanic trainning in Hampshire. (no sign of an ECU in those days except on Honda's).
annyone would think I'd committed a cardinal sin on here mind you these are the people that swear you should only change engine oil every 6K so I expect people to be lazy about things these days.
An initial top up charge to ensure maximum capacity and then two charges a year isnt doing any harm at all. and I never get these flat battery days when the car wont start. when outside temps get down to minus 18 dgrees C a maintenance charge set to frost with an initial high amp charge followed by a trickle charge is no bad thing.

[Northern_Mike]

You need to get some new batteries in yours and your dad's cars and get your charging circuits checked.

I've only ever had flat batteries when the alternator has been iffy, or in the case of my Focus, when the original, 12 year old battery failed internally. I have never had to charge a new battery, and as the calculations done by others in this thread show, a modern alternator will charge a battery to full in very little time.

I change the oil every 10k. It says 12500 in the book. A bit early doesn't do it any harm. 6000 on a TD is about right. I'd do it earlier on a 2cv..

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[elmerfud]

Many thanks for all the responses to my problem, it now seems to have righted itself.....maybe I`m just a worrier.