Flat Battery - best course of action?
Discussion
I'm just going to add another "the battery should be fine - get the car started, take it for a 40 min drive with A/C, heaters, lights off (radio is OK) and it should be fine. If it's NOT fine, THEN you need a new battery".
Age means nothing - brand means something tho. The difference between an OEM or decent brand battery and the cheapest one you can get at the local motor factor is - well - I'd rather have a 5-year-old decent one than that new one!!
If you DO buy a new one, buy a noted brand/buy from somewhere with a 2+ year warranty on it (means it will actually last much longer).
I've had too many motor factor batteries which last JUST over the 12 months they offer (if you're really lucky, just under which gives you still short of 2 years!!)
Age means nothing - brand means something tho. The difference between an OEM or decent brand battery and the cheapest one you can get at the local motor factor is - well - I'd rather have a 5-year-old decent one than that new one!!
If you DO buy a new one, buy a noted brand/buy from somewhere with a 2+ year warranty on it (means it will actually last much longer).
I've had too many motor factor batteries which last JUST over the 12 months they offer (if you're really lucky, just under which gives you still short of 2 years!!)
chongwong said:
Jump starting the car and leaving it running for an hour or so,even in neutral should work fine, discharging the battery shouldn't have done any damage. If you have anybody nearby that you can rely on for a push, just push start it, shove it back in your drive and leave it running for a while, or depending on the length of your commute, just drive it to work or wherever you're going, and that should be sufficient
If the car has an alternator as opposed to a dynamo ( most cars from about 1970 onwards ) then bump starting with a completely flat battery is inadvisable : the battery will demand high current and the diode/regulator pack in the alternator will not cope - result = knackered alternator .A jump start is OK since you can allow the battery to take some charge from the other vehicle for a few minutes both before and after starting , then keep the car which had the flat battery running for at least half an hour to put a reasonable charge back in .
If the battery was otherwise healthy and only discharged overnight by leaving lights on , I would not replace it - just either jump start or charge and refit . Carry jump leads for a few days just in case it fails again - if it does fail again , then replace , but chances are it will be OK .
Aldi/Lidl do very good 'intelligent' chargers every so often for about £15 .
chongwong said:
Sorry,but I think in this case you're wrong, leaving the car at idle for an hour, maybe 2 should have the battery fully charged, I work at a long stay car park , and we do have battery chargers, but because of the comparative speed of jump starting the vehicles and leaving them at idle we don't bother using them:-) I agree with the rest of your points though, also OP if leaving it at idle, try leaving the headlamps on whiles it's running as that 'seems' to speed up the process a little bit
just my shiny little 2 pence
That last point is just plain silly - sorry . just my shiny little 2 penceLeaving headlamps , or any other non essential equipment , on is just an additional load on the alternator and consumes current that could otherwise go to charging the battery . The alternator will provide the best charging current when the engine is running somewhat above idling speed , so taking the car for a run is the best way to charge the battery ; it will take longer to charge if left to idle because the output of the alternator is lower at idle speed ; once the engine is running fast enough for the generator to reach full charging voltage ( circa 14.8 V for a 12 V system ) the output is regulated to avoid over charging and newer cars have an OVP ( over voltage protection ) relay to prevent damage to electronic components .
In short , just driving the car for between half an hour to an hour should charge the battery back up .
The alternator will charge at 50-100 amps while a small , domestic battery charger will output only a few amps and requires overnight , possibly 24 hours , to fully recharge a flat battery . You can get 'industrial' chargers capable of higher output ( I have a Crypton 200A max charger in my garage , but it can actually damage batteries if you force too much current through them for any length of time , best to charge at a lower level .
I would recommend a jump start followed by a run and see how the battery performs ; carry jump leads in case it fails again and only replace in that case .
I am a qualified electrical engineer , so I know what I am talking about .
I'll update this evening on how the battery's doing (hopefully not from the NCP!).
Will the battery charge more quickly when the engine is idling or at moving speeds - or does it make no difference?
I'll be driving for about 30/40 mins mixed traffic before parking up.
It's a 45 Ah battery and there are no computers or sophisticated electronics on board.
Will the battery charge more quickly when the engine is idling or at moving speeds - or does it make no difference?
I'll be driving for about 30/40 mins mixed traffic before parking up.
It's a 45 Ah battery and there are no computers or sophisticated electronics on board.
martinalex said:
I'll update this evening on how the battery's doing (hopefully not from the NCP!).
Will the battery charge more quickly when the engine is idling or at moving speeds - or does it make no difference?
I'll be driving for about 30/40 mins mixed traffic before parking up.
It's a 45 Ah battery and there are no computers or sophisticated electronics on board.
it'll charge quicker at moving speeds as far as i'm aware. for a battery like that on a car with no fancy electrics it'll charge pretty quickly. 40 mins driving will be more than enough to ensure it'll start next time.Will the battery charge more quickly when the engine is idling or at moving speeds - or does it make no difference?
I'll be driving for about 30/40 mins mixed traffic before parking up.
It's a 45 Ah battery and there are no computers or sophisticated electronics on board.
B'stard Child said:
matchmaker said:
Some right b
ks being spouted on here. I'll tell you my thoughts from 35 years of motoring and plenty of flat batteries.
1. The battery is very unlikely to be knackered so you won't need a new one.
2. Get the car started (by whatever means) and go for a good drive. An alternator will provide a far greater charging current than any domestic battery charger. You're not driving a car with a bloody C40L dynamo!
Been there, done it, carry the jump leads.
And still being spouted after your postks being spouted on here. I'll tell you my thoughts from 35 years of motoring and plenty of flat batteries.1. The battery is very unlikely to be knackered so you won't need a new one.
2. Get the car started (by whatever means) and go for a good drive. An alternator will provide a far greater charging current than any domestic battery charger. You're not driving a car with a bloody C40L dynamo!
Been there, done it, carry the jump leads.
Pontoneer said:
chongwong said:
Sorry,but I think in this case you're wrong, leaving the car at idle for an hour, maybe 2 should have the battery fully charged, I work at a long stay car park , and we do have battery chargers, but because of the comparative speed of jump starting the vehicles and leaving them at idle we don't bother using them:-) I agree with the rest of your points though, also OP if leaving it at idle, try leaving the headlamps on whiles it's running as that 'seems' to speed up the process a little bit just my shiny little 2 pence
That last point is just plain silly - sorry . just my shiny little 2 penceLeaving headlamps , or any other non essential equipment , on is just an additional load on the alternator and consumes current that could otherwise go to charging the battery . The alternator will provide the best charging current when the engine is running somewhat above idling speed , so taking the car for a run is the best way to charge the battery ; it will take longer to charge if left to idle because the output of the alternator is lower at idle speed ; once the engine is running fast enough for the generator to reach full charging voltage ( circa 14.8 V for a 12 V system ) the output is regulated to avoid over charging and newer cars have an OVP ( over voltage protection ) relay to prevent damage to electronic components .
In short , just driving the car for between half an hour to an hour should charge the battery back up .
The alternator will charge at 50-100 amps while a small , domestic battery charger will output only a few amps and requires overnight , possibly 24 hours , to fully recharge a flat battery . You can get 'industrial' chargers capable of higher output ( I have a Crypton 200A max charger in my garage , but it can actually damage batteries if you force too much current through them for any length of time , best to charge at a lower level .
I would recommend a jump start followed by a run and see how the battery performs ; carry jump leads in case it fails again and only replace in that case .
I am a qualified electrical engineer , so I know what I am talking about .
Once it’s flat it’s kackered is one of those pieces of advice you often get from people who were once told it by their dad many years ago.
It’s not true – but it might be true in a different context or situation.
A flat battery freezes at a much lower temp then a charged battery.
And a frozen battery destroys the internal plates and kills it.
So; many years back a 18 year old in their first escort rings their dad from a phone box at 2am after a night out.
- Dad, I left the light on, the batteries dead. It’s snowing. I don’t know what to do.
- It’s alright son, if the batteries totally flat it’ll be knackered by now you’ll need to get a new one in the morning. I’ll come and collect you.
Home safe and well. Breakdown chap jump started it and said to keep it running for an hour and that it would be charged up fine.
Left it running on idle and then did a mixed route over 40 mins or so before parking up for the day.
Eight hours later, started up fine. Been in and out to the shops now too with no problems starting again.
Very pleased with how it has gone and hopefully no need for a new battery. Still wary of it failing again but fingers crossed it will start in the morning.
Left it running on idle and then did a mixed route over 40 mins or so before parking up for the day.
Eight hours later, started up fine. Been in and out to the shops now too with no problems starting again.
Very pleased with how it has gone and hopefully no need for a new battery. Still wary of it failing again but fingers crossed it will start in the morning.
Snowboy said:
Once it’s flat it’s kackered is one of those pieces of advice you often get from people who were once told it by their dad many years ago.
It’s not true – but it might be true in a different context or situation.
A flat battery freezes at a much lower temp then a charged battery.
And a frozen battery destroys the internal plates and kills it.
So; many years back a 18 year old in their first escort rings their dad from a phone box at 2am after a night out.
- Dad, I left the light on, the batteries dead. It’s snowing. I don’t know what to do.
- It’s alright son, if the batteries totally flat it’ll be knackered by now you’ll need to get a new one in the morning. I’ll come and collect you.
Do you mean a flat battery freezes at a higher temperature relative to a charged one?It’s not true – but it might be true in a different context or situation.
A flat battery freezes at a much lower temp then a charged battery.
And a frozen battery destroys the internal plates and kills it.
So; many years back a 18 year old in their first escort rings their dad from a phone box at 2am after a night out.
- Dad, I left the light on, the batteries dead. It’s snowing. I don’t know what to do.
- It’s alright son, if the batteries totally flat it’ll be knackered by now you’ll need to get a new one in the morning. I’ll come and collect you.
Thread resurrection!
Battery is flat in my E36 3 Series. Not surprised as I don't use the car very often. It isn't totally dead - I get loads of clicking and buzzing noises and the dashboard lights up like Amsterdam when I try to start the car.
It's a nine year old Bosch Silver S4 004 which has been perfect up to this point. Will a bump start and a long drive be enough? I'm not sure.
Battery is flat in my E36 3 Series. Not surprised as I don't use the car very often. It isn't totally dead - I get loads of clicking and buzzing noises and the dashboard lights up like Amsterdam when I try to start the car.
It's a nine year old Bosch Silver S4 004 which has been perfect up to this point. Will a bump start and a long drive be enough? I'm not sure.
martinalex said:
Breakdown chap jump started it and said to keep it running for an hour and that it would be charged up fine.
I had this exact scenario with my previous battery. It had been in the car for about eight years and went flat when I left the car parked for several hours with an interior light on during the winter. The breakdown guy told me the same - long drive after he'd jump-started it - but I had a catalogue of battery related issues after that and ended up replacing it with the aforementioned Bosch Silver. I know nine years is a long time for a battery, though I've read about people having Bosch Silvers still going strong after 12 years, so would a good run or a proper charge be the way to go or should I just celebrate a good innings and buy a new one?Edited by MitchT on Friday 21st October 12:04
R300will said:
Snowboy said:
Once it’s flat it’s kackered is one of those pieces of advice you often get from people who were once told it by their dad many years ago.
It’s not true – but it might be true in a different context or situation.
A flat battery freezes at a much lower temp then a charged battery.
And a frozen battery destroys the internal plates and kills it.
So; many years back a 18 year old in their first escort rings their dad from a phone box at 2am after a night out.
- Dad, I left the light on, the batteries dead. It’s snowing. I don’t know what to do.
- It’s alright son, if the batteries totally flat it’ll be knackered by now you’ll need to get a new one in the morning. I’ll come and collect you.
Do you mean a flat battery freezes at a higher temperature relative to a charged one?It’s not true – but it might be true in a different context or situation.
A flat battery freezes at a much lower temp then a charged battery.
And a frozen battery destroys the internal plates and kills it.
So; many years back a 18 year old in their first escort rings their dad from a phone box at 2am after a night out.
- Dad, I left the light on, the batteries dead. It’s snowing. I don’t know what to do.
- It’s alright son, if the batteries totally flat it’ll be knackered by now you’ll need to get a new one in the morning. I’ll come and collect you.
MitchT said:
Thread resurrection!
Battery is flat in my E36 3 Series. Not surprised as I don't use the car very often. It isn't totally dead - I get loads of clicking and buzzing noises and the dashboard lights up like Amsterdam when I try to start the car.
It's a nine year old Bosch Silver S4 004 which has been perfect up to this point. Will a bump start and a long drive be enough? I'm not sure.
Most batteries that are the wrong side of 5 years or so do not survive a deep discharge. There's no harm in trying but it'll take more than an hour on idle or driving around to completely recharge it. Best to take it out and charge it with a battery charger. Better still, charge it with an 'intelligent' charger such as a CTek - these have programmed charging cycles that can recover a pretty dead battery.Battery is flat in my E36 3 Series. Not surprised as I don't use the car very often. It isn't totally dead - I get loads of clicking and buzzing noises and the dashboard lights up like Amsterdam when I try to start the car.
It's a nine year old Bosch Silver S4 004 which has been perfect up to this point. Will a bump start and a long drive be enough? I'm not sure.
martinalex said:
Breakdown chap jump started it and said to keep it running for an hour and that it would be charged up fine.
I had this exact scenario with my previous battery. It had been in the car for about eight years and went flat when I left the car parked for several hours with an interior light on during the winter. The breakdown guy told me the same - long drive after he'd jump-started it - but I had a catalogue of battery related issues after that and ended up replacing it with the aforementioned Bosch Silver. I know nine years is a long time for a battery, though I've read about people having Bosch Silvers still going strong after 12 years, so would a good run or a proper charge be the way to go or should I just celebrate a good innings and buy a new one?Edited by MitchT on Friday 21st October 12:04
MitchT said:
Battery is flat in my E36 3 Series. Not surprised as I don't use the car very often.
So being discharged by memories, alarm etc all the time.MitchT said:
It isn't totally dead - I get loads of clicking and buzzing noises and the dashboard lights up like Amsterdam when I try to start the car.
Enough in there to fire up the electrics, but as soon as you try to demand current for the starter, you just run out of juice, and the voltage drops sufficiently for the relays etc to disengage.[quote=It's a nine year old...
Quick look at one of the online suppliers suggests 096 or 027. <£50 for an Exide, <£80 for a Bosch.
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