New Battery - FLAT
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Not many rules really, this board being aimed at technical issues, it shouldn't fall foul (hopefully) of some of the more personal issues that can affect forums.
Rule 1 - Is that you need to think very carefully before posting anything technical or asking anything technical relating to the security system of the car - See 'Security Issues' sticky for more info.
Rule 2 - We (MGF Register) do not support copyright infringement and therefore references to CD ROM, PDF versions or paper copies of the workshop manual (for instance) should not be posted on the forum. We don't want to get into trouble and we'd rather sell you a genuine hard copy through our Regalia shop anyway!
Because advice is honestly and freely given in this technical section, much of it will be amateur experienced based, so any information is given in good faith and is not guaranteed as correct.
Not many rules really, this board being aimed at technical issues, it shouldn't fall foul (hopefully) of some of the more personal issues that can affect forums.
Rule 1 - Is that you need to think very carefully before posting anything technical or asking anything technical relating to the security system of the car - See 'Security Issues' sticky for more info.
Rule 2 - We (MGF Register) do not support copyright infringement and therefore references to CD ROM, PDF versions or paper copies of the workshop manual (for instance) should not be posted on the forum. We don't want to get into trouble and we'd rather sell you a genuine hard copy through our Regalia shop anyway!
Because advice is honestly and freely given in this technical section, much of it will be amateur experienced based, so any information is given in good faith and is not guaranteed as correct.
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johncooper
- Posts: 45
- Joined: Sun May 04, 2008 5:01 pm
- MGF Register Region: South East
- Model of Car: MGTF 135 M.G. M type
New Battery - FLAT
Last June I brought a new battery for my late wife's MGF/TF 135, I give it a run a couple times a week. Yesterday it started normally and as I drove off down the road a warning light came on it was the Airbag SRS, then other warning lights came on, I couldn't tell which as I was negotiating a roundabout. Then the engine stopped and I lost all power and of course the steering became heavy. I drifted to a stop and was recovered back to my home about 3/4 of a mile away. Everything is absolutely dead even the driver's door seems to have locked itself. The battery was brought on 6th June 2023 new from Halfords, it is a B HCB075. Is there anything that could have occurred in the car that would have caused such a failure? I don't want to get a new battery and the same thing reoccur. Many thanks.
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Reckless Rat
- Posts: 1889
- Joined: Tue Apr 01, 2008 9:01 am
- MGF Register Region: Europe
- Model of Car: 97 1.8mpi in BRG
- Location: South of France - in the Gard.
Re: New Battery - FLAT
If the battery is less than a year old then it should still be under warranty and Halfords should replace it, providing you still have the original receipt.
However when you say you "give it a run" a couple of times a week, do you actually take the car out and run it for 10-15 miles at least, or do you just start it and let it tick-over for a minute or two? - you'll need at least a decent run out to put back in the energy you've taken from the battery to start the car. It may just be that the battery is flat because your occasional "use" has depleted it. Have you kept the car connected to a battery conditioner or smart charger?
If not the on-board electronics can have a habit of draining the battery and the failure you mention is a symptom of a dead battery. It may well charge back up... You should be able to get the car started by using a couple of jump leads (+ve to +ve and -ve to -ve). If the battery doesn't come back then go back to Halfords.
However when you say you "give it a run" a couple of times a week, do you actually take the car out and run it for 10-15 miles at least, or do you just start it and let it tick-over for a minute or two? - you'll need at least a decent run out to put back in the energy you've taken from the battery to start the car. It may just be that the battery is flat because your occasional "use" has depleted it. Have you kept the car connected to a battery conditioner or smart charger?
If not the on-board electronics can have a habit of draining the battery and the failure you mention is a symptom of a dead battery. It may well charge back up... You should be able to get the car started by using a couple of jump leads (+ve to +ve and -ve to -ve). If the battery doesn't come back then go back to Halfords.
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johncooper
- Posts: 45
- Joined: Sun May 04, 2008 5:01 pm
- MGF Register Region: South East
- Model of Car: MGTF 135 M.G. M type
Re: New Battery - FLAT
Yes I do take it for a decent spin a couple of times or more a week, especially if the weather is nice. Yes I do have the receipt. When my wife was alive she occasionally didn't use it for 10 days or more if we were away, by which time the battery wouldn't start it, the alarm etc running the battery down. But a quick jump and off it would go. This time as soon as I disconnected the slave battery the same happens, warning lights came on, instruments stopped working, engine stopped. What I haven't done is try to recharge the battery and see if it holds a charge. The meter shows no voltage at all, I would have expected at the very least 3 or 4 volts.
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Chris Tideswell
- Posts: 828
- Joined: Mon Oct 08, 2007 5:58 pm
- MGF Register Region: Midlands
- Model of Car: TF 135
- Location: Shepshed Leicestershire
- Contact:
Re: New Battery - FLAT
Sounds like it could be a failed alternator, when the ignition is turned on (without starting the engine) does the battery warning light aluminat? If not then the alternator has failed.
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Notanumber
- Posts: 115
- Joined: Thu Aug 03, 2023 3:48 pm
- MGF Register Region: South East
- Model of Car: TF 135 Sunstorm
Re: New Battery - FLAT
First of all check if the battery has an internal fault. Occasionally one of the cells in a battery can just fail which results in substantially reduced voltage being stored. I have experienced this. The way to tell is to put the battery on charge for a while, leave it all day/ night if you can and check the read out on the charger to make sure it is putting some charge into the battery. Then take it off charge, leave it for a couple of hours and then check the voltage across it. If it is anything less than 12.4 volts under those circumstances then the battery is most likely to have a problem. I did this on one battery for someone recently and saw less than 10 volts at that point = a definite internal battery failure.
If you have proved the battery is alright then as Chris T says the alternator is the next culprit. With a charged battery in place A start the car and allow it to idle for a few mins. Put a multimeter across the + and - check the voltage. . B with the engine still running turn the headlights on full beam and measure again. C turn the headlamps and ignition off then measure again. D make sure the engine is not running and just turn the headlamps on. Write down the voltages each time. If the alternator is good the reading should be highest when the engine is running and not make much difference when the headlamps are switched on with the engine running. If the readings for A and B are no higher than those for C and D then you have an alternator fault. Very often you can get away with changing the regulator in the alternator without having to replace the whole unit as it's this that usually fails.
If you have proved the battery is alright then as Chris T says the alternator is the next culprit. With a charged battery in place A start the car and allow it to idle for a few mins. Put a multimeter across the + and - check the voltage. . B with the engine still running turn the headlights on full beam and measure again. C turn the headlamps and ignition off then measure again. D make sure the engine is not running and just turn the headlamps on. Write down the voltages each time. If the alternator is good the reading should be highest when the engine is running and not make much difference when the headlamps are switched on with the engine running. If the readings for A and B are no higher than those for C and D then you have an alternator fault. Very often you can get away with changing the regulator in the alternator without having to replace the whole unit as it's this that usually fails.
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Rob Bell
- Committee Member
- Posts: 14425
- Joined: Tue Oct 02, 2007 2:36 pm
- MGF Register Region: South East
- Model of Car: MGF 1.8i + MGF Shed!
Re: New Battery - FLAT
If you could start and then drive the car only for the battery to later discharge itself points very strongly towards a charging fault.
The Bosch alternators on the later TF are a weak point (the earlier Marelli Magnetti alternators are far more robust), but that would not be the place I'd start having recently had similar issues.
The commonest problem on a car that hasn't had a huge amount of use are dirty/oxidised connectors. The commonest area seems to be around the main battery connection or alternator connection to the starter motor. That's where I had problems and it is a relatively simple and cheap thing to fix (remove terminals and clean them up!)
Do let us know where your fault finding takes you John!
The Bosch alternators on the later TF are a weak point (the earlier Marelli Magnetti alternators are far more robust), but that would not be the place I'd start having recently had similar issues.
The commonest problem on a car that hasn't had a huge amount of use are dirty/oxidised connectors. The commonest area seems to be around the main battery connection or alternator connection to the starter motor. That's where I had problems and it is a relatively simple and cheap thing to fix (remove terminals and clean them up!)
Do let us know where your fault finding takes you John!