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Magenta

Long-Term Battery Problem.

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I wonder if any auto-electricians out there have any ideas on this irritating problem I have had pretty well throughout the four-year life of my Fiesta ?

I have had a succession of battery failures, going either almost or completely flat, usually overnight for no obvious reason. Each time they checked, the AA proved there was a good output from the alternator and there was no current drain. The Ford dealer subsequently changed first the alternator and then the battery under warranty (although I am not convinced that the battery they fitted was a new one).

I eventually put the problem down to the frequent very short journeys I do and fitted an LED voltmeter plugged in to the power socket to monitor the battery voltage.

Usually, the voltmeter shows about 12.2 volts static and after start up and sometimes goes up to 14 v settling down to around 13.0 - 13.2 whilst driving. I have taken to putting it on trickle charge every few weeks which I think should not be necessary.

The battery failed again only last week which was quite inconvenient.

What has prompted this particular post is that while out yesterday, I noticed that the voltage dropped to only 11 volts with no lights or heated screen on which quite concerned me. To see how low it would drop with a load, I switched on both heated screens, half expecting the engine to cut out but to my surprise it actually rose to 13.2 and stayed there after I switched the screens off.

When I got home I kept the engine running and double checked the reading across the battery with my Fluke testmeter and it showed a normal 13.2 - 13,5v, confirming the LED reading inside the car.

The car has only done 17,000 miles in four years.

Anyone have any ideas ?

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the only thing i can think of is lack of use, thats all, my dads mg tf convertible has the same problem its stored for 6months of the year but a new battery and has already had 2 alternators as they just dont get turned over enough to keep them going, thats the only experiance i have had with regards to this, but there may be a problem else were, but id say just infrequanct use tbh if you take it for a good long run maybe 150+ miles im sure it would last and build up the battery life again, but batteries never like to be run down only really like to be trickle charged as there is a limit on the amount of cycles of charge a battery can handle and if you dont use your car for say 2 weeks the battery will naturally deplimish and then gets charged up again when you use it, so its a constant cycle were as if you use the car everyday the battery wont have enough time overnight to deplimish. thats my view on it m8 hope it helps

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Thanks, I suspect you are on the right track. The car is used regularly but perhaps not every single day but only (usually) for very short trips of 2-3 miles so I suspect the clue is there. I was just surprised at how soon the battery seems to run down, almost as if I was running on battery alone but the alternator test seems to indicate it is ok. My late mother in law used to have this problem for the same reason but the battery would only go flat after six or nine months.

I am a retired electrical engineer and did work on battery technology for some years during one period so I know a little about it but it is still a puzzle..

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what type of battery is it? lead acid, gel? i work with batteries at work so i could do some digging to help you, but i very much expect the problem is the amount of miles it does, if you charge a normal aa battery for the same amount of time you charge your car battery in those 3 miles its pointless, i bet the battery doesnt even recover the amount of energy used to start the car and all the systems on board, if the alternantor is all good, have you double checked the connections for any hot points?

how old is the battery you have in now? and whats the rating on it? ampers per hour?

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what type of battery is it? lead acid, gel? i work with batteries at work so i could do some digging to help you, but i very much expect the problem is the amount of miles it does, if you charge a normal aa battery for the same amount of time you charge your car battery in those 3 miles its pointless, i bet the battery doesnt even recover the amount of energy used to start the car and all the systems on board, if the alternantor is all good, have you double checked the connections for any hot points?

how old is the battery you have in now? and whats the rating on it? ampers per hour?

Hi,

The battery is a standard Ford branded 'sealed' low maintenace with only a small vent hole. It is described as 'Silver Calcium' but I suspect it is a lead acid gel type. The specification is: 43 ampere hour, 390 cca (which is probably the max short term current value), Ford Finis 1672940, Part 8G9N-10655-LA, 12v 65. The letters after the 65 are blurred but could be R6. As I said this was the replacement fitted by the Ford dealer and has a hand written 'Tested Dec 2012' sticker on it.

I have checked all the visible connections I can reach and they tight and in good nick.

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Hi,

The battery is a standard Ford branded 'sealed' low maintenace with only a small vent hole. It is described as 'Silver Calcium' but I suspect it is a lead acid gel type. The specification is: 43 ampere hour, 390 cca (which is probably the max short term current value), Ford Finis 1672940, Part 8G9N-10655-LA, 12v 65. The letters after the 65 are blurred but could be R6. As I said this was the replacement fitted by the Ford dealer and has a hand written 'Tested Dec 2012' sticker on it.

I have checked all the visible connections I can reach and they tight and in good nick.

thats exactly the same battery i have from when the car was new, 5 years ago, its not low rated so im sure your not using all that current to bog it down, and if all the general connections ie alternator to battery is fine i dont see why its not charging, it either bad luck with a dodgie batch of batteries, just not enough running to keep it charged or there is something else wrong inside the car. have you double checked the battery saver is working? ie sit in the car and lock it with the fob wait 30-35mins (its boring i know ive done it haha) and then all lights and sounds should be off, only thing still on is the immboliser light on the dashboard, which is the only thing left powered up when locked, but then that only draws milliamps so that would never drain a battery. im stumped with you m8 tbh, if you can try and use it for longer trips and see what its like, but after that i would say if ford or even a local garage could help but they would only check what we have talked about, and then probs just stick another battery in, so i have no more ideas tbh sorry

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thats exactly the same battery i have from when the car was new, 5 years ago, its not low rated so im sure your not using all that current to bog it down, and if all the general connections ie alternator to battery is fine i dont see why its not charging, it either bad luck with a dodgie batch of batteries, just not enough running to keep it charged or there is something else wrong inside the car. have you double checked the battery saver is working? ie sit in the car and lock it with the fob wait 30-35mins (its boring i know ive done it haha) and then all lights and sounds should be off, only thing still on is the immboliser light on the dashboard, which is the only thing left powered up when locked, but then that only draws milliamps so that would never drain a battery. im stumped with you m8 tbh, if you can try and use it for longer trips and see what its like, but after that i would say if ford or even a local garage could help but they would only check what we have talked about, and then probs just stick another battery in, so i have no more ideas tbh sorry

The only light that stays on for a while is the amber 'locked' light and that goes out after about 2 minutes. You are dead right that current drawn on each start up has to go back in somehow but It does seem odd that in such a modern car that short trips run the battery down so quickly. I have had many classic cars even back in the days of dynamos (remember them ?) and one in particular used to stand unused for months on end but would usually still start. In fact, I did have this problem once with my previous mk 7 Fiesta (a diesel) but it only let me down once on a snowy day and we jumped into the VW Beetle to go out and it started after standing for months !

Significantly, I believe the diesel models have a larger battery for the extra torque needed to turn these engines. In my opinion, 43ah in the petrol engined Fiesta is skimping a little.

I will continue to monitor and trickle charge my battery and thanks for all your advice.

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i get what you mean its not heard of very often considering how reliable alternators are meant to be, and i only know of the dynos from wheeler dealers :L good old ed china haha as this is my first car ive only worked on the alternator myself, i beleive the diesels have a 60 or even 75ah battery for the extra effort on a cold day, but still petrols can be unreable to start in cold weather, over xmas i nearly gave up waiting for mine to tick over, and it is ford at the ne dof the day haha they will save money where they can, the designers probs worked out the car needs 42ah battery to be substainable and ford kept the bare min, yh let me know how you get on and if a longer drive changes anything. no worries pal

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Im not an auto electrician but an electronics engineer with a different, specialized background. i also worked for Ford, and am an expert in Mondeos, and tuning engines, and other related things

The 1st thing i would say is that the AA is incorrect to say there is no load on the battery when the car is sitting, locked up with the battery connected - there is a small but significant load, things like the central locking, parts of the cars electronics, like the ECU, are constantly on, even with the ignition off

If i leave my car sitting for more than a couple of weeks without starting it, the battery will not have enough charge to start the engine, i have fitted a small, solar panel to help this (£10 from maplin, i sit it on the dash) - this helps to compensate for the power loss, if the car is to be laid up for a long time, i disconnect the battery (this will reset the ECU and i would have to put the radio code in again)

I agree with D, in that your short journeys are not (re)charging your battery, they used to say that a car needed a 20 minuite drive to recharge the battery, to put back in what you took out by starting it - this does not mean there are other problems

There must be a "break even" point, where you have replenished the power you have taken out, i would imagine this would be longer than 3miles/ 5 mins - if you continually do short journeys, the battery power can get progressively lower and lower, combined with the (small) constant drain the battery will eventually run flat enough that it cannot start the engine - it does not mean there is anything wrong with the car/ battery (to start with, anyway)

If a lead-acid battery (including silver- calcium) goes flat, it reduces its capacity and can "total" it - it is best to keep it charged - this can compound the above problem

Modern cars have a smart-charge system, (these require a silver-calcium battery) when the battery is cold, it can increase the voltage, this is what happened when the OP put his heated screens on, in the 1st post

Although the smart-charge system increases the rate of charge on a modern car, and the alternator has a realatively high output, there is a lot of electrical equipment on a modern car, some of which has a large power drain, so the demands on the battery of a modern car may be much higher than with a "classic" car certain things, like the heated screen, have a large power drain

In the winter lead-acid batteries performance is reduced, and with shorter days (lights on more often) and electric heaters being used winter can put a significant extra strain on the battery - in artic countries the battery may have a higher raiting (on an otherwise identical car)

I recommend you upgrade your battery to a higher capacity, this will "prop up" any underling problems, or lack of (sufficient) use, it may seem an un-nessesary expense, but weigh this against the inconvenience/ potential lost income/ extra expense etc if the car does not start, - if you could not let it get flat/ low - it should keep its performance

You could also reduce the load, like fitting LEDs etc inside and out, even changing the interior light to LEDs can make a surprising difference, fitting a solar panel trickle charger can help too, keeping an eye on the battery voltage and topping it up when it gets low is a good idea

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If its not the short journeys you might have a problem with a component thats draining the battery you need an auto electrician to check itout

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Thanks, that is all interesting advice. I like the idea of the solar trickle charging, I have seen these but the problem is the car is usually in the garage this time of the year (not so much in the summer and is also handy to hook up the charger) so I'm not sure how much light it would get. In the last few days I also had considered upgrading the battery size as you suggest. It seems a sensible move.

When I called the AA out (at least twice) to this problem, they clipped a current detector on the battery lead to test for current drain and the result was a negligable reading, not enought to cause a problem. The same meter also showed a healthy input to the flat battery from the alternator (30 amps at the time I think). As an ex electrical engineer, I do have what we used to call clamp meters for measuring AC current but does anyone know where can I get a device such as the AA used for clamping on to DC cables ? I don't really want to start disconnecting the battery cables.

Harking back to the days of dynamos, we used to use centre-zero ammeters on the dash and you could see which way the current was flowing which was great ! Not so easy with an alternator but I do accept that an alternator system is far superior.

I have considered trickle charging via the power outlet in the car so that I don't have to keep lifting the bonnet - can anyone see a problem with this (my battery charger has only about 5 amps output).

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Thanks, that is all interesting advice. I like the idea of the solar trickle charging, I have seen these but the problem is the car is usually in the garage this time of the year (not so much in the summer and is also handy to hook up the charger) so I'm not sure how much light it would get. In the last few days I also had considered upgrading the battery size as you suggest. It seems a sensible move.

When I called the AA out (at least twice) to this problem, they clipped a current detector on the battery lead to test for current drain and the result was a negligable reading, not enought to cause a problem. The same meter also showed a healthy input to the flat battery from the alternator (30 amps at the time I think). As an ex electrical engineer, I do have what we used to call clamp meters for measuring AC current but does anyone know where can I get a device such as the AA used for clamping on to DC cables ? I don't really want to start disconnecting the battery cables.

Harking back to the days of dynamos, we used to use centre-zero ammeters on the dash and you could see which way the current was flowing which was great ! Not so easy with an alternator but I do accept that an alternator system is far superior.

I have considered trickle charging via the power outlet in the car so that I don't have to keep lifting the bonnet - can anyone see a problem with this (my battery charger has only about 5 amps output).

The current drain the AA read is probably within tolerance, and would not be a problem on a car that was used more frequently, for longer trips (or a longer trip to replenish the battery at least now and again)

But with the ECU/ central locking etc, i have a feeling the current drain on a modern car is a lot more than a classic car

The drain may be tiny (and not more than any other similar car, so not a "fault") but its like a dripping tap, that tiny drain builds up over time, so it will eventually flatten the battery if left long enough

Strictly speaking, you are not supposed to charge the battery with it still connected to the car, but i do it myself, you can also get devices with batteries built into them to keep the power (so you don't loose the ECU settinggs radio code etc) when the battery is charged, that plug into the cigar lighter socket - i see no reason you could not charge the battery the same way - it would be easy for you to make up a plug that comes off the battery charger + 5A is no problem, i think the cigar lighter socket/ plug handles 20A?

You could even get a 12v solar panel stick it on the roof of the garage, and charge the battery with it, a second/ seperate battery and it could power your garage lights (12v LED lights) free, once you've got the hardware

I really wanted an ammeter too, but they say you are better off with voltmeter with an alternator, the ammeter has to split the power too, which can have reliability issues, wheras the voltmeter can be connected anywhere without "hacking" the cars' loom

The more i read - the more im thinking there is nothing much wrong with the car and its just the way its used / it could be considered a design flaw or it simply was never intended to be used like that - it depends on your perspective

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I have bought a solar panel from Maplins for £9.99 as suggested by FOCA. At that price it's worth giving it a try. Thanks.

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