Done to death battery drain
Discussion
Hi,
A much discussed subject on this forum, and I've learned a lot by reading about it .Unfortunately I still can't solve the battery drain prob on my 280i.
I've tried: Pulling all the fuses (in the glove box - are there any more?), disconnecting alternator, checking the starter motor lead for chafing , removed an in line fuse going to an amp in the boot.
The test lamp stays resolutely on no matter what I've tried. Two odd things - the battery has only been flat twice, but both times completely dead not even enough juice to give a flicker on the ignition warning light. Also when I put the test lamp into the cicuit it lights up brightly for a second then dims, which looks like a capacitor sort of issue, but I'm certainly no expert.
Is there anything else I could try?
Thanks
Ian
P.S the fuel gauge has yesterday started reading full but I can't see any short in the wiring. I don't know if the issues are connected
A much discussed subject on this forum, and I've learned a lot by reading about it .Unfortunately I still can't solve the battery drain prob on my 280i.
I've tried: Pulling all the fuses (in the glove box - are there any more?), disconnecting alternator, checking the starter motor lead for chafing , removed an in line fuse going to an amp in the boot.
The test lamp stays resolutely on no matter what I've tried. Two odd things - the battery has only been flat twice, but both times completely dead not even enough juice to give a flicker on the ignition warning light. Also when I put the test lamp into the cicuit it lights up brightly for a second then dims, which looks like a capacitor sort of issue, but I'm certainly no expert.
Is there anything else I could try?
Thanks
Ian
P.S the fuel gauge has yesterday started reading full but I can't see any short in the wiring. I don't know if the issues are connected
Hi Ian
Just a thought....On my 280i I used to knock the interior light under the dash to the right of the steering wheel with my knee when getting out...I was baffled for ages as I would cover the car up and come back a couple of days later and it was flat as a pancake...It wasn't until I needed a socket for a job indoors one night that I saw the light on when I uncovered her...
Just a thought....On my 280i I used to knock the interior light under the dash to the right of the steering wheel with my knee when getting out...I was baffled for ages as I would cover the car up and come back a couple of days later and it was flat as a pancake...It wasn't until I needed a socket for a job indoors one night that I saw the light on when I uncovered her...
As Zig says, I've done the interior light trick too......
Other suggestions -
1. alternator regulator can fail and become 'leaky' . it doesn't have a fuse.....try disconnecting alternator and retest....
(oops I see you've been there................)
2. If you have central locking, that unit can fail too.
Original Ford setup (in granada) didn't have a fuse in its supply, but locks did. - don't know if wedge has one.
Um, something which is not fused and always connected....
Ignition amplifier ? (was fused on mine though)
Radio/stereo ? (most units have supply to keep settings memory alive
Faulty fuel relay ?
Cig lighter ? (yeah, go ahead, laugh ..... but it's always connected !!)
Other suggestions -
1. alternator regulator can fail and become 'leaky' . it doesn't have a fuse.....try disconnecting alternator and retest....
(oops I see you've been there................)
2. If you have central locking, that unit can fail too.
Original Ford setup (in granada) didn't have a fuse in its supply, but locks did. - don't know if wedge has one.
Um, something which is not fused and always connected....
Ignition amplifier ? (was fused on mine though)
Radio/stereo ? (most units have supply to keep settings memory alive
Faulty fuel relay ?
Cig lighter ? (yeah, go ahead, laugh ..... but it's always connected !!)
Edited by RCK974X on Saturday 5th August 22:25
Are the light pods fully retracted? If not the motor stays live and will flatten the battery in no time. See this thread.
To eliminate this possible fault; switch the lights on to raise the pods, disconnect the battery, disconnect the connector blocks in each side of the nose cone, reconnect the battery and see what happens. If the battery retains its charge you've isolated the current leak.
To eliminate this possible fault; switch the lights on to raise the pods, disconnect the battery, disconnect the connector blocks in each side of the nose cone, reconnect the battery and see what happens. If the battery retains its charge you've isolated the current leak.
I found the electrical drain in mine. A non-functional alarm system, a non-functional stero system, and three switches doing God knows what tied into the mess was draining my battery in no time (5 to 10 days). A modern Kenwood head and new Alpine speakers of original size and location for direct replacement have everything working ticky-boo now. (There lots of good security options that won't drain the battery too.) This is the lot I ripped out last year. Another 16 feet of wire came out yesterday; an auto dimming mirror that doesn't got the chop. 
Thanks guys for all the suggestions.
There isn't a clock in mine, though there there is a fuse for one, and there's a fuse for the radio also one for the radio memory, plus cigar lighter.
I've had all the fuses out that I can find, plus another in-line one I've just spotted in a red cable from the battery positive. No idea what that's for, I see I'm going to have to invest in that SH bible.
I'll try the lights/motors idea to see what happens.
Re the interior light suggestion, only one works (even though the bulbs are ok) which can't be right. Having said that, there's a fuse for them too.
I'll take it out for a spin now (if it'll start!) to have some fun before today's aggravation.
Ian
Update, just noticed that the dash voltmeter clicks between 12 and 14 when the indicators are on! Never seen that one before....
Also the headlights don't get brighter when the engine is revved (alternator kaput?)
Plus the engine slows down when the cooling fan comes on (alternator OK?).
Oh, and the fuel gauge worked correctly for a minute or two.
For a car that goes well, and looks good, it's really 'entertaining' in the electrical department!
There isn't a clock in mine, though there there is a fuse for one, and there's a fuse for the radio also one for the radio memory, plus cigar lighter.
I've had all the fuses out that I can find, plus another in-line one I've just spotted in a red cable from the battery positive. No idea what that's for, I see I'm going to have to invest in that SH bible.
I'll try the lights/motors idea to see what happens.
Re the interior light suggestion, only one works (even though the bulbs are ok) which can't be right. Having said that, there's a fuse for them too.
I'll take it out for a spin now (if it'll start!) to have some fun before today's aggravation.
Ian
Update, just noticed that the dash voltmeter clicks between 12 and 14 when the indicators are on! Never seen that one before....
Also the headlights don't get brighter when the engine is revved (alternator kaput?)
Plus the engine slows down when the cooling fan comes on (alternator OK?).
Oh, and the fuel gauge worked correctly for a minute or two.
For a car that goes well, and looks good, it's really 'entertaining' in the electrical department!
Edited by madformotors on Sunday 6th August 13:55
It sounds to me as you have a series of electrical problems accumulated over the years rather than just one problem. My guess would be something along the lines of bad earthing problem together with a unit that drains your system and perhaps an alternator that's not charging or not charging sufficiently. I would start by checking and refurbishing all earth points. Then disconnect any new or old alarm systems and try and work out what is draining by an elimination process. Also, check that the alternator is charging sufficiently by using a volt meter across the battery terminal when car is idling to see if it's reading around 14.5V. It's all a lengthy process but you'll get there if you dig hard enough. It's the joys of TVR ownership. Good luck.
Tony. TCB.
Tony. TCB.
Thanks Tony, I'm sure you're right.
I've jumped straight in at your last point - alternator. My cheapo multi meter says the battery alone is 12V, but when the engine is idling it's about14V. That seems OK, BUT when I do an AC volts test on the alternator output to earth, instead of a 'ripple'of 2 V, it's about 30.
So, I'm sure my low mileage but 30 year old car might have all sorts of gremlins, but it definitely needs the alternator repairing/ replacing.
Ian
I've jumped straight in at your last point - alternator. My cheapo multi meter says the battery alone is 12V, but when the engine is idling it's about14V. That seems OK, BUT when I do an AC volts test on the alternator output to earth, instead of a 'ripple'of 2 V, it's about 30.
So, I'm sure my low mileage but 30 year old car might have all sorts of gremlins, but it definitely needs the alternator repairing/ replacing.
Ian
Edited by madformotors on Sunday 6th August 16:08
Well the alternator just chucks raw AC through some diodes and out of the terminal, there isn't any smoothing as such, so you would expect to see quite a bit of ripple.
What's your indicator lamp like? Is it a LED or a bulb? When you say it dims after the initial flash, does it dim to dim, or nothing at all?
To get a better handle on these things this is what I do:
1. Set the multimeter on amps (0-1.999A range)
2. Loosen the earth lead on the battery post but keep it connected.
3. Attach one multimeter lead to the battery earth lead.
4. Put the other lead on the head of the post.
5. Pull the earth lead off the post, but don't touch the multimeter lead.
You'll now get a good measure of the leakage current into the loom, but avoiding any capacitor charging pulses from alarms etc. which might pop the fuse in the multimeter.
The 12V/14V flicker with the indicators is fairly common to all wedges and as Tony says cleaning up the earths is a good move that might help here. However the earths don't affect battery drainage - this is independent of earthing.
Also bear in mind that I would disconnect my battery when I go away for a week or more, I have done this with all my wedges and don't regard this as excessive drain, it's just the way that '80's electronics are. By modern standards it's pretty high so if you are judging it too stringently you might be making a headache for yourself unnecessarily.
What's your indicator lamp like? Is it a LED or a bulb? When you say it dims after the initial flash, does it dim to dim, or nothing at all?
To get a better handle on these things this is what I do:
1. Set the multimeter on amps (0-1.999A range)
2. Loosen the earth lead on the battery post but keep it connected.
3. Attach one multimeter lead to the battery earth lead.
4. Put the other lead on the head of the post.
5. Pull the earth lead off the post, but don't touch the multimeter lead.
You'll now get a good measure of the leakage current into the loom, but avoiding any capacitor charging pulses from alarms etc. which might pop the fuse in the multimeter.
The 12V/14V flicker with the indicators is fairly common to all wedges and as Tony says cleaning up the earths is a good move that might help here. However the earths don't affect battery drainage - this is independent of earthing.
Also bear in mind that I would disconnect my battery when I go away for a week or more, I have done this with all my wedges and don't regard this as excessive drain, it's just the way that '80's electronics are. By modern standards it's pretty high so if you are judging it too stringently you might be making a headache for yourself unnecessarily.
Hi Adam,
Thanks for that thought-provoking stuff. The dead battery syndrome has occurred twice, both times on overnighters, but not yet when left for a week, oddly enough. Since the second one, I've been disconnecting the battery.
Thanks for the battery drain check procedure, I'll give that a try, after I've invested in a decent multimeter. Oh and the bulb I've been using is a normal filament one BTW.
Cheers ,
Ian
Thanks for that thought-provoking stuff. The dead battery syndrome has occurred twice, both times on overnighters, but not yet when left for a week, oddly enough. Since the second one, I've been disconnecting the battery.
Thanks for the battery drain check procedure, I'll give that a try, after I've invested in a decent multimeter. Oh and the bulb I've been using is a normal filament one BTW.
Cheers ,
Ian
It sounds intermittent then.
I had a one-off on the 400SX when the headlamps were on when the pods were down and lights switched off. I only caught it because it was getting to twilight and I noticed a glow from the front when I returned to the car. And the pods were noticeably warm. It did flatten the battery but I left it disconnected for 10 minutes and there was just enough life and a warm engine and the car started on the first turn.
I suspect that the dim-dip module had got into a funny state (I had flashed the lights at someone earlier). It has never happened since - touch walnut veneer...
I had a one-off on the 400SX when the headlamps were on when the pods were down and lights switched off. I only caught it because it was getting to twilight and I noticed a glow from the front when I returned to the car. And the pods were noticeably warm. It did flatten the battery but I left it disconnected for 10 minutes and there was just enough life and a warm engine and the car started on the first turn.
I suspect that the dim-dip module had got into a funny state (I had flashed the lights at someone earlier). It has never happened since - touch walnut veneer...
madformotors said:
Update, just noticed that the dash voltmeter clicks between 12 and 14 when the indicators are on! Never seen that one before....
I think that's pretty standard - My S series does that too. But to be honest its the only real indication that the indicators are on, so at least I notice after a few miles of errant flashing..That's a good point - I'm not usually guilty of errant flashing (oo-er missus), but maybe that's because in my sensible car I can see the flasher lights/hear the clicking. Whereas in the TVR my hands on the wheel cover the dash lights, and as for hearing anything above the exhaust, well no chance! The time I did notice the gauge jumping I was in fact guilty of forgetting to flick the indicators off, so maybe this quirk is a bonus after all!
Ian
Ian
At last! The 'drain' has been found - just not by me. I had to admit defeat and let the professionals look at it.
The upshot was that it had three incorrect relays fitted, one of which had melted, along with some wiring and the relay socket. Apparently the rogue relays looked right and 'fitted' but the terminals did different things from the correct ones. The drain was 0.25 A which I'm told a) was about 6 times the 'acceptable' amount and b) apparently I'm lucky the car didn't catch fire. The leak was on the live side of the fuse box (I must admit I was beginning to suspect this) which is why taking the fuses out didn't highlight the fault.
It's not back together yet (looks a mess with wires apparently everywhere) but I'm looking forward to getting it mobile again. There's some mechanical niggles still, but at least I'm comfortable with sorting them myself.
Dreading the bill though!
Ian
The upshot was that it had three incorrect relays fitted, one of which had melted, along with some wiring and the relay socket. Apparently the rogue relays looked right and 'fitted' but the terminals did different things from the correct ones. The drain was 0.25 A which I'm told a) was about 6 times the 'acceptable' amount and b) apparently I'm lucky the car didn't catch fire. The leak was on the live side of the fuse box (I must admit I was beginning to suspect this) which is why taking the fuses out didn't highlight the fault.
It's not back together yet (looks a mess with wires apparently everywhere) but I'm looking forward to getting it mobile again. There's some mechanical niggles still, but at least I'm comfortable with sorting them myself.
Dreading the bill though!
Ian
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