stchris356
New Member
IF you have a 110ah battery that's draining in half an hour then you have one serious fault forget about a 0.6a drain and the accepted drain should be no more than 50mA (0.05A) but to obtain this reading you normally have to wait for the BCM etc to go into sleep mode, not sure how long that takes on RR but I'd expect it to take no longer that 1/2 hour.
One thing I would check is to see(without the engine running) if the alternator or starter is getting hot because other than glow plugs (if it's a diesel) theres nothing capable of that kind of drain in that timescale and I have come across an alternator and starter with a dead internal short before now causing this kind of drain, hope that helps.
One thing I would check is to see(without the engine running) if the alternator or starter is getting hot because other than glow plugs (if it's a diesel) theres nothing capable of that kind of drain in that timescale and I have come across an alternator and starter with a dead internal short before now causing this kind of drain, hope that helps.
Goodfella
New Member
Fully charged this morning and is now reading 13.7v cold and 14.7v running and same with the headlights.
Mate last night left his multimeter but don't know how to use this to read drain, but it started fine this morning so am going to leave it all day and see later this afternoon if anything has changed.
Thanks for all the ideas.
Mate last night left his multimeter but don't know how to use this to read drain, but it started fine this morning so am going to leave it all day and see later this afternoon if anything has changed.
Thanks for all the ideas.
47p2
New Member
Can I just add that every time you open a door/bootlid/bonnet etc you will wake up the system and it will take up to 30 minutes to go to sleep again. All the time it's awake it is using valuable battery power. Lock the car and walk away until you are ready to try it later this afternoon
Goodfella
New Member
Done it again! Battery was 11.7v after starting the car/turning it off an hour ago and was 13.7v while running. Less than an hour later of leaving the negative terminal attached again and on trickle charge the battery reads 5.11v, totally dead. So its back on charge again now with the neg terminal lead off.
Datatek
Well-Known Member
Goodfella
New Member
Well that reading was correct I think, tried on two different meters.
The shine of buying this car has quickly drained away i can tell you, i have no confidence in it when it is running despite its great condition and history, if someone wanted it now i would snap their hands off! So much for luxury motoring, thinking i should have kept my Forester as it didn't miss a beat!
The shine of buying this car has quickly drained away i can tell you, i have no confidence in it when it is running despite its great condition and history, if someone wanted it now i would snap their hands off! So much for luxury motoring, thinking i should have kept my Forester as it didn't miss a beat!
Datatek
Well-Known Member
A P38 is not a car, it's a career in motor mechanics and electronics. If you don't like to play it ain't the car for you.
At the end of the day you are blaming the car when it's most probably the battery. For a 110 amp hour battery to discharge in an hour you would have to be drawing enough current to start a bloody fire
dogsbody
Very senior member
The trouble with reading voltages alone is that they don't really tell you the true condition of the battery. Either go back to where you bought it, or even a Halfords or Kwik Fit type place and get them to test the battery.
Mind you getting a battery down to 5.5 volt takes some doing and if it's honestly gone flat in one hour I'd expect the car to glow in the dark.
Mind you getting a battery down to 5.5 volt takes some doing and if it's honestly gone flat in one hour I'd expect the car to glow in the dark.
Goodfella
New Member
Well it was charged up again last night to 12.81v, at 9am this morning it is reading 12.41v and i left the negative terminal disconnected all night. I assume the car couldn't have taken the power with only positive connected could it?
So although it hasn't dropped drastically am i right in thinking the new battery should have maintained at least 12.7v overnight? If so I'll have to go and swap it .
Just put the negative lead back on without waking the car up so will see if it starts to drain more in the next hour. Noticed key code lockout message on the dash but not tried opening it up yet.
So although it hasn't dropped drastically am i right in thinking the new battery should have maintained at least 12.7v overnight? If so I'll have to go and swap it .
Just put the negative lead back on without waking the car up so will see if it starts to drain more in the next hour. Noticed key code lockout message on the dash but not tried opening it up yet.
stchris356
New Member
Firstly reconnecting the battery itself will "wake" the car and secondly a volt meter is not really much help on it's own, you really need an amp meter as that will tell you the drain from the battery to the vehicle.
Did you notice if there was a large arc between the battery and the terminal when connected?
If so I'd recommend using an amp clamp rather than a meter as if the drain is over 10A it will blow the internal fuse in the meter, the clamp just clamps arouns the cable and will give a good reading but it's not that accurate below 100mA (0.10 A).
If the volt meter is all you have, connect and observe the voltage without starting the car or turning the ignition on for about an hour.
If after the hour the voltage is still around 12v then get someone to attempt start the engine whilst observing the volt meter, if the cranking voltage drops below 10v then I would SUSPECT the battery at fault BUT I'm guessing the battery was replaced due to the same symptoms and as in my previous post for that kind of drain it would have to be something capable of pulling that amount of current, I once had a TDV6 with exactly the same symptoms and traced that back to the alternator pulling 97.00A
and it was fused at 110A I couldn't even touch the alternator as it was that hot!Anyway good luck and if the volt meter has an amp scale on it, let me know and I'll talk you through how to connect it if that helps.
Chris.
Forgot to answer your question the car cannot drain power from the battery with only one terminal connected either pos or neg and 0.4V isn't enough to condem a battery!
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stchris356
New Member
It's impossible to determine the amount of drain from the spark but as it's considerable that tells me it's quite a large drain and therefore a 10A meter would not be a good starting point, you will get a spark from almost every car when the battery is connected but if it's with quite an audible "crack" that would suggets quite a large drain, before you go any further do you have breakdown cover?
Goodfella
New Member
Well i give up for today, couldn't get it going to take to Halfords so will just charge it again overnight. Its been connected for a few hours and current reading is flickering between 5.11v and 8.2v while relay is clicking under the engine fusebox.
Thanks for everyone's suggestions so far, appreciate them all .
Thanks for everyone's suggestions so far, appreciate them all .
stchris356
New Member
Personally I'd avoid Halfords on the diagnosis side of things, if you have breakdown cover with either RAC or AA I'd be calling them out because a battery will drain for one of three reasons.
1, Knackered battery and they have good battery testing equipment.
2, Battery being insufficiently charged either by alternator or just lack of use. They can test alternator.
3, The battery is being drained, they carry amp clamps and amp meters and should be able to carry out an amp drain test.
You need to point out to the patrol (once you've made him a coffee) that the battery has been replaced due to this fault and it also goes completly flat in a very short time and this should set him off thinking theres a drain on this!
If you have cover with Green Flag etc I'd let the leccy look at it as most(not all before I'm shot down) don't have the equipment or knowledge to carry out the above tests and will just want to tow it away!
1, Knackered battery and they have good battery testing equipment.
2, Battery being insufficiently charged either by alternator or just lack of use. They can test alternator.
3, The battery is being drained, they carry amp clamps and amp meters and should be able to carry out an amp drain test.
You need to point out to the patrol (once you've made him a coffee) that the battery has been replaced due to this fault and it also goes completly flat in a very short time and this should set him off thinking theres a drain on this!
If you have cover with Green Flag etc I'd let the leccy look at it as most(not all before I'm shot down) don't have the equipment or knowledge to carry out the above tests and will just want to tow it away!
Personally I'd avoid Halfords on the diagnosis side of things.
1, Knackered battery and they have good battery testing equipment. Halfords use the same kit as the AA or RAC around here (Bosch)
2, Battery being insufficiently charged either by alternator or just lack of use. They can test alternator. Halfords use the same kit as the AA or RAC around here (Bosch)
3, The battery is being drained, they carry amp clamps and amp meters and should be able to carry out an amp drain test. So do some Halfords (We do).
It all boils down to the competance (or not) of the user. Not all AA/RAC peeps are good either.
