Flat Battery after long break in use

Undecided

Undecided

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Hi
I have a 2002 1.4 petrol A2. Unfortunately it hasn’t been touched for 4 months and the battery is completely flat. The battery is about 4 years old. I was planning to remove the battery to charge it. I have read there are issue with lost codes if you do that. Or is it the case that as the battery has been flat for a while that those codes are already lost? Another option I might have is to get home start out to give it a boost charge in situ. Any advice welcome.


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Have you got a smart charger? CTEK or similar?. Leave the battery in the car and see if the charger can recover the battery. Hook the charger up to the battery in the boot and leave it for at least 24hours. You might be lucky.
 
Thanks. I think I will try a smart charger first. Tanya have the Ctek 5 for about £65 at the moment. Are there any cheaper alternatives?


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If the radio is an OEM unit and its code was previously entered in this car, the car and the radio will remember each other even though power was lost. The remote keyfobs will need resynching and the one-touch window settings refreshing though. Keyfobs - Ignition on, then off then immediately lock & unlock on the fob. Windows - for each one, all the way down and hold for 10 seconds, then all the way up and hold for 10 seconds, do one at a time.
 
The technique for reviving a totally flat battery is to charge it in parallel with another battery. It's surprising how even a "dead" battery can be brought back to life! This is the method used by "Tayna" who are based very near to me at Abergele on the North Wales coast.

David
 
My Ctek charger (it's a boggo MXS 5.0, I think) doesn't like a completely flat battery. It either just sits there and does nothing (as though there's no battery connected to it) or it flags a battery fault but offers no magic fix. Either way, it doesn't bring a flat one back from the dead.

However, if I connect said dead-as-a-dodo battery to my trusty old-school Absaar charger, that doesn't take No for an answer. It'll just shove charge into whatever I put in its path. So I use that for a few hours, to get something into the battery, then switch to the Ctek. At which point, the Ctek decides Yes, there is a battery there. From there, you can run the recon routine on it and that very often restores the battery to a usable state, if not Good As New.

@DJ 190 - I like the idea of charging with a battery in parallel. Might just give that a try. Thanks for the suggestion! ?
 
Yes you may get a charge into the totally flat battery but its capacity will have been greatly reduced. Smart reconditioning chargers can help but once capacity is lost its down hill from there. Nothing worse than thinking great its charged then try and start the car and find there is no capacity in the battery and almost instantly goes flat. Flat once or twice but left flat for extended period, good luck. I suggested just replacing the battery because to try a battery reconditioner and it fails you will still need a battery. If the 4 year old battery is a quality one there is a chance if budget probably not.
 
Morning all. Thanks for all the advice so far. I have bought the Ctek Mxs 5 as it will be useful for the future. I realise the battery may be a dead duck. Have just connected the charger across the battery terminals whilst still in the car. Key was not in the ignition. Started the program on the charger and the hazard lights started to flash. All the dash lights were flashing too. Turned the charger off again. Should I be disconnecting the battery first? Or are the flashing lights nothing to worry about.


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Undecided said:
Morning all. Thanks for all the advice so far. I have bought the Ctek Mxs 5 as it will be useful for the future. I realise the battery may be a dead duck. Have just connected the charger across the battery terminals whilst still in the car. Key was not in the ignition. Started the program on the charger and the hazard lights started to flash. All the dash lights were flashing too. Turned the charger off again. Should I be disconnecting the battery first? Or are the flashing lights nothing to worry about.


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Click to expand...
There is no reason to disconnect the battery before charging, indeed CTEK provide an optional connector lead to do this permanently and something that attracted me to buy one recently, very convenient.

CONNECT CLAMP

56-262
www.ctek.com www.ctek.com

Click on FAQs on the right then battery and select the question.

However something is wrong with these flashing dash lights. You have selected the correct operating mode? Probably because the battery is so flat so do as audifan suggests and disconnect battery.

Andy
 
Last edited:
TFG said:
My Ctek charger (it's a boggo MXS 5.0, I think) doesn't like a completely flat battery. It either just sits there and does nothing (as though there's no battery connected to it) or it flags a battery fault but offers no magic fix. Either way, it doesn't bring a flat one back from the dead.

However, if I connect said dead-as-a-dodo battery to my trusty old-school Absaar charger, that doesn't take No for an answer. It'll just shove charge into whatever I put in its path. So I use that for a few hours, to get something into the battery, then switch to the Ctek. At which point, the Ctek decides Yes, there is a battery there. From there, you can run the recon routine on it and that very often restores the battery to a usable state, if not Good As New.

@DJ 190 - I like the idea of charging with a battery in parallel. Might just give that a try. Thanks for the suggestion! ?
Click to expand...
This is exactly what I do too. Start with a few hours on a "dumb" charger then switch to my Ctek smart charger; preferably via use of the recondition mode.
 
Andrew said:
There is no reason to disconnect the battery before charging, indeed CTEK provide an optional connector lead to do this permanently and something that attracted me to buy one recently, very convenient.
Click to expand...
For recond program (which I think should be run on a fully flat battery), I would disconnect the battery, because it charges with higher voltage and this could damage some modules. Probably A2 should be ok since modules are quite old, but on newer cars…
Anyway, I would disconnect it. And for recond program I would make sure the plastic airvent pipe is connected to the battery. If it is missing, leave the boot open.

STEP 6 RECOND
Choose the Recond program to add the Recond step to the charging process. During the Recond step voltage increases to create controlled gassing in the battery. Gassing mixes the battery acid and returns energy to the battery.
 
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mtl said:
For recond program (which I think should be run on a fully flat battery), I would disconnect the battery, because it charges with higher voltage and this could damage some modules. Probably A2 should be ok since modules are quite old, but on newer cars…
Anyway, I would disconnect it. And for recond program I would make sure the plastic airvent pipe is connected to the battery. If it is missing, leave the boot open.

STEP 6 RECOND
Choose the Recond program to add the Recond step to the charging process. During the Recond step voltage increases to create controlled gassing in the battery. Gassing mixes the battery acid and returns energy to the battery.
Click to expand...
Thank you for your comment but I know little about battery charging and can only go by what CTEK state, they are the experts.

As it happens I have never added the Recond option to the standard Car charging mode. I do note the CTEK booklet with the charger recommends adding the Recond option once per year and I should get round to doing it. However I will take your advice and disconnect the battery when I do.

Andy
 
mtl said:
For recond program (which I think should be run on a fully flat battery), I would disconnect the battery, because it charges with higher voltage and this could damage some modules. Probably A2 should be ok since modules are quite old, but on newer cars…
Anyway, I would disconnect it. And for recond program I would make sure the plastic airvent pipe is connected to the battery. If it is missing, leave the boot open.

STEP 6 RECOND
Choose the Recond program to add the Recond step to the charging process. During the Recond step voltage increases to create controlled gassing in the battery. Gassing mixes the battery acid and returns energy to the battery.
Click to expand...
According to CTEK, the maximum voltage in recond mode is 15.8v, which shouldn't cause any damage. In recond mode, voltage and current are pulsed. There is little or no gassing now in modern batteries, due to the use of Antimony-free Lead. That's why you don't have to top them up.

RAB
 
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