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The battery in my little-used third car died just before christmas, not terminal but just because I don't use the car very much. I made the mistake of using the electric tyre pump to sort the tyres before starting her up & checking how much juice she had..... As I was going away for christmas and new year, returning home late yesterday evening, today is the first chance I've had to get the battery on charge. Is it likely to survive, given that it is only two years old and a top-notch battery?
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Yes,and if it doesn't take it back under the guarantee!
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Yes and if it doesn't take it back under the guarantee!
Not as easy as it sounds- the car is in the UK and the battery was fitted in Austria - from whence I have just returned in another car!
Thanks for all the other replies, I'm going to put it on charge and see what happens. I'll be more careful in future, especially if it costs me a new battery!!
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Batteries left in a discharged state for a long period of time, especially in cold weather very rarely recover. Check the ammeter reading on your charger when you re-charge it. If the amps reading is very low at first and then stays low it's a very good chance the battery is unserviceable. A serviceable battery that is simply discharged will accept a higher current draw. In any case you're going to have to leave it on a trickle charge for about 8-10 hours to get it to a fully charged state.
If you know that you're going to be leaving the car for weeks at a time, and especially during the colder months it's a good idea to use your battery charger to charge the battery overnight about once per month to keep it in good condition, and also to prolong it's life. You don't need a several hundred pound battery tester to test your battery. The test below is absolutely concrete.
To test the battery do as follows:
1. Before the engine has been started that morning check the battery voltage. A fully charged battery will read about 12.6V. Anything less than 12.2V and the battery is in a discharged state.
2. If the voltage is higher than 12.2V disconnect the crankshaft sensor to prevent the engine from starting. It's not a good idea to just disconnect the ignition coil and fuel will be injected when you crank it and collect in the catalyst.
3. Crank the engine for a minimum of 10 seconds and observe the battery voltage whist doing so. A healthy battery will measure at least 10V on a petrol engine, and 9.5V on a diesel whilst cranking, but more importantly the voltage must not drop by more than 0.3V during those 10 seconds of cranking. So for example, during cranking the battery measures 10.5V but drops to 10.3V after 10 seconds. In this case the battery is serviceable.
You will generally find that the voltage during cranking will fall away quite quickly on a battery that is no good. They are usually very easy and obvious to spot.
A good battery tester can cost anywhere up to £500, but essentially they work by placing the battery under load and measuring the voltage, as well as the battery's internal resistance. This is however a very fancy way of testing it, and you don't need to buy one, or go to anyone who has one to accurately check the condition of your battery.
A voltmeter is also very useful for identifying bad battery connections, bad starter motor connections, and bad engine earths by doing volt-drop tests. Ask me and I'll explain how to do it if you're not sure. If you have an amp-clamp you can also test starter motor current draw which is also very useful, and can also give the appearance of a flat battery......
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Even if you do manage to get it to take some charge, the battery will be severely weakened. My toddler daughter left a rear courtesy light on which flattened the nearly new battery over a weekend. Even after 2 hours charging at about 6 Amps the engine still would not turn over. I left it overnight on trickle charge and it worked OK. However it failed completely after a year. Car batteries are optimized for starting with lots of very thin plates. They don't like being dicharged fully.
KISS
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The test by railroad is a good indicator of battery (but not quite concrete as suggested).
Other problems on the car can cause voltage drop whilst cranking so use it as a guide rather than gospel.
However, a decent battery left discharged for 2 or 3 weeks is not a good idea, but should with luck recover. But it needs a steady very low trickle charge, ideally for a few hours, then rest, then repeat, until it holds steady voltage at around 12.5 to 12.6 v.
When it reaches this figure it then needs to stand for around 4 hours for re check on voltage and then (and only then) refit it to the vehicle. Once started it should then be taken for a 20 minute drive. Allow it to stand for 2+ hours still connected to the car and check voltage again. It still needs to be holding at (12.4 absoloute minimum) 12 .5 to 12.6v.
hth
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The test by railroad is a good indicator of battery (but not quite concrete as suggested). Other problems on the car can cause voltage drop whilst cranking so use it as a guide rather than gospel.
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It is true that other problems may give the appearance of a flat battery such as poor starter motor or solenoid connections, high resistance cables, bad engine earth and even a faulty starter motor. These can be checked out very easily with a multi-meter, but assuming that there are no problems in these areas then the above test can pretty much be taken as gospel.
In any case if there were to be some other fault battery voltage will be dragged down, but it will reach a point where it will stop. This should enable the diagnosis to point to away from the battery. In the case of a faulty battery the voltage will continue to fall steadily.......
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I've been trying to revive a couple of dead batteries for a few weeks now - my seldom used car battery failed just after its 2 year guarentee. Unfortunately I have had no success but I can tell you the process :
To de-sulphate a battery :
1) Use a pulsator charger, such as the Ring or CTEK ones. I bought a cheap CTEK copy from ALDI, only used for a few days, not automatically switched to maintenance mode yet so still a little hope.
2) Epsom salts. 1 teaspoon in each cell and trickle charge for a month
3) Caustic soda. A pinch in each cell. Unfortunately I was too impatient and used a teaspoon in each cell and 1 battery is now FUBARed
Worth a shot. You haven't got anything to loose if it doesn't revive by normal charging. Obviously be very careful and protect your eyes/hands etc. when handling battery acid and caustic soda!
Would be nice to hear from anyone who has had sucess.
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How about sealed batteries ? I recall reading somewhere that these don't 'sulphate up' like old style ones, or have I been mislead?
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If you do leave a car without running the engine for long periods then I would buy the type of battery charger that can be left permanently on and use that. I bought one in Lidl for about £13 and have left it on a Fiat Cinquecento that has not moved for 1.5 years. The car still starts first time.
I see that Aldi have a similar charger at a similar price at the moment, certainly cheaper than a new battery.
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Any battery should be able to stand two weeks flat;if they can't do that,they are not worth buying.
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>>Any battery should be able to stand two weeks flat;if they can't do that,they are not worth buying.<<
Nearly a fair point, but..... This battery was still connected to the vehicle and being subjected to continuous drain (albeit light drain).
It is not a good idea to allow a battery to do this and whilst a good battery should recover it is not definite; and would not be automatically covered under the guarantee. With the price of batteries soaring currently most suppliers are looking long and hard at any warranty claims and many insist on it being returned to factory for full inspection/report before any claim is entertained.
A battery should always be stored in a charged condition.
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If you do leave a car without running the engine for long periods then I would buy the type of battery charger that can be left permanently on and use that.
I always understood that the battery has to be disconnected from the car to avoid damage while charging, which is what I have currently done. Is this not the case?
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