battery / alternator problem

[madmaninshed]

Hi, Thanks to lots of kind help from people on blatchat I thought my was car just about ready for a trip to France with other Caterhams next Thursday. Unfortunately after it started fine this morning, I gave it a good run and then stopped at Halfords. When I got back in it a few minutes later, the battery was flat and the engine wouldn't turn over. (no, I hadn't left the lights on!). I bought the car very recently and the battery, which is just over a year old and under guarantee, was flat when I picked it up. It was an 80 mile run home, and after jump starting, it was fine. It re-started ok when I refuelled on the journey. Since then, I have trickle charged it occasionally and it has been fine. So why the sudden problem when the engine was hot and easy to turn over?

I decided to check that the ignition light comes on with the fuel pump etc ....but it doesn't.....so I can't check that the charging circuit is ok by seeing that it goes out as revs are increased. If i can get the car started, can I put a meter acros somewhere to check for charging? The car is a starter kit with 2.0 duratec. It was wired professionally, but it certainly doesn't look neat. Maybe they didn't bother wiring the ignition light in the speedo???

Do banner batteries of this age suddenly fail. The car has been used very little, and the engine has done about 1k miles so is very tight. The electrolyte level looks fine. Any thoughts would be much appreciated. Thanks, Paul.

[madmaninshed]

Sorry...should add that 2 guys at Halfords kindly bump started the car, and it ran fine for about 5 miles to get me home. I put the battery on a conditioner, and 3 lights on the conditioner came on, then a fourth. I tried starting the car after a couple of hours, and it turned over a couple of times slowly, but not quickly enough to start.

[Beelzebub]

I would suggest the first thing to do is to find out why the alternator light is not working. ISTR that the lamp is an integral part of the circuit that energises the alternator. There can be enough residual magnetism to make the alty function but I'd check the lamp to see if the filament's intact. Whilst you're at it check its wire to the alty &the earth from the lamp.

 

Allow your battery to rest for approx two hours off charge & off load. This allows any surface charge to disipate & you should be able to read approx 13 V across the battery. Start the car & this should rise to around 14.4 V if the alty is functioning. If it does'nt you'll have to find out why.

 

If your Banner's been left discharged for any length of time it could be sulphated & in need of replacement. It's a one way process I'm afraid.

 

To summarise: make sure the alty is functioning & then determine if the battery's holding a charge.

 

D.

[shn7]

can I put a meter acros somewhere to check for charging?

 

Yes. A volt meter across the battery terminals is what you need. Everything off it should read 12.5 - 13V. Engine running above tickover this should rise to around 14V.

 

Steve.

Sussex (West) AR

Not forgetting Percy the Polar Bear

[madmaninshed]

Thanks guys, it is a brand new speedo as another LCD display was failing, so the lamp should be ok. Wish I'd checked it out on the old speedo before I packed it up to send it back. Will get the meter out and start checking as suggested. Thanks again - I hadn't a clue where to start. I'll make it to France & back somehow!!!Cheers, Paul.

[madmaninshed]

As the battery would not turn the engine over to start it, I trickle charged it overnight, then got up early to leave off charge for over 2 hours as suggested. Sadly the charger (which showed 3 lights lit when I started the charge) now shows one red one. Even the headlamps hardly glow. The battery is under warranty....but came from 80 miles away from me. If it wasn't dead before...it sure is now. I shall call the supplier and see how the warranty works. In the meantime, if I borrow a normal car battery, perhaps I can start the engine and do the check on the alternator etc. There are 3 connections to the alternator. One is a link that goes from one of the spade connectors to elsewhere on the alternator. After months of the car running fine, the previous owner found that the battery discharged if it wasn't used much (my thoughts are due to the immobilizer??). He removed this link, and after my problems yesterday (believing it must have been there for a reason) I replaced it. 😳

[shn7]

Paul,

 

I suggest, once you've got this sorted, you get a decent battery conditioner and whenever the car's not in use connect it to this.

 

Leaving the car for prolonged periods (weeks) with the immobiliser armed will drain the battery and result in sulphation of the plates. This eventually gets you to a point where the battery won't hold sufficient charge to start the car. This could be the whole of your problem and the alternator may well not be at fault.

 

Connecting a std car battery to test the alternator output voltage should be fine.

 

No idea about that link you mention though.

 

Steve.

Sussex (West) AR

Not forgetting Percy the Polar Bear

[madmaninshed]

Found a Banner battery locally in Worthing ready charged. Connected it up and got just a little spark as I connected the last (-ve) terminal - more than I would have expected the immobilizer to draw...but.. Put meter across terminals with everything off. Got 12.39 V. Then started the car (engine turned over easily) and got 12.06 on fast'ish tickover (think cold start kicks in). When I rev the engine this went up to 13.5V. Because of the slight spark when I connected the battery, I have disconnected it again just in case there could be something wrong that will drain the battery. Is 13.5 V sufficient? Should I take a reading with the headlamps and other accessories on? What if the battery has been in stock for a while? I'll put a conditioner on it anyway.

[ashaughnessy]

Am I not correct in thinking that the banner battery is a wet one that needs its electrolyte levels checking? If so, have you checked them?

 

Sounds like your original battery was in bad condition. The ignition light not coming on when the engine isn't started sounds likely to be caused by the totally flat battery. Cause of said battery flatness still needs to be determined. If the electrolyte levels were severly diminished then this would be a likely explanation of all your symptoms but you might still want to check that you don't have a short to earth somewhere that is draining it while stopped. I've no idea how much current the immobiliser will draw. If it has flattened your battery then it has indeed done what it says on the tin :-)

 

Anthony

[Beelzebub]

Madman.

 

Pending the accuracy of your voltmeter, 13.5V is not enough to fully charge your battery. If this is what your alternator is putting out it warrants further investigation. With the engine running I'd expect to see around another volt but no more. Can you borrow another MM & check the accuracy of your findings ?

 

D.

[madmaninshed]

Hi Anthony, I did check the levels and they were ok. The old battery was in a state! Once the battery conditioner has the green light on indicating a full charge, I'll check the voltages stopped, ticking over and revving again. With luck, all may be ok. There is definately no ignition light, and I will try to check that out this evening. Unfortunately the people who wired the car up are still not contactable.

[madmaninshed]

Thanks Dave, Good idea - will do.

[madmaninshed]

Having trickle charged the new battery in the car the night before, to find in the morning the battery was flat and charger was dead I had an auto electrician visit yesterday. He checked out the charging etc and also the ignition light. He said there was only 4v across the light rather than 12v, which was why it wasn't illuminated when the ignition was sitched on. He thought this was not a problem, and tested charging etc. He gave it a clean bill of health and said it wouldn't need any further charging....Brilliant!!! Unfortunately not......battery is totally dead this morning. Tried to get new alternator as a last resort, but nobody can identify part nos. Not enough time left now anyway, so tomorrow's 3 day French trip now cancelled ....

[shn7]

Sorry to hear the bad news. I guess you won't be recommending the services of said auto-electrician then . I suppose that gives you 3 days to spend trying to fix it. Not that that's much consolation. Thereagain you could come along to the w. Sussex meeting at the Gribble tonight to drown your sorrows and chat about how to fix it. 😬

 

Steve.

Sussex (West) AR

Not forgetting Percy the Polar Bear

[madmaninshed]

Thanks Steve, I would but can't make it tonight. The electrician seemed very professional, but either may have missed something, or perhaps something moved a bit and is now shorting out. Who knows...I sent him a text at 8am but no response yet. Perhaps his mobile is wired incorrectly . With the help of people on blatchat my handling / steering and oil pressure reading problems are all solved, but just got stuck on this one. I think a full Raceline loom, alternator on the other side of the engine (away from the exhaust), cam cover, hoses etc etc are needed. There is no hurry now, so can take my time. Will post what the problem is hoping to help someone else with similar symptoms, and will post about solutions to bump steer and oil pressure reading soon. Cheers, Paul.

[ashaughnessy]

I'm still very confused - if your battery is totally flat then of course the ignition light won't come on. What's the alternator got to do with it?

 

You say you got a new battery - is this new battery in the car? Is it the new battery that is now flat?

If a brand new battery has flattened in that short space of time, what have you done in that time? Have you driven the car or left it idle?

 

When you installed the new battery, did the ignition light come on with the engine stopped when the battery was fresh? If not, light or alternator is at fault. otherwise light and battery are OK but alternator unproven.

 

If the battery has flattened during driving, alternator is probably at fault (though may be simply the connections that are loose).

 

If the battery has flattened while the car is idle, then alternator is a red herring and you must look for a drain or short somewhere (which may include the alternator or may not).

 

I think I'd like to hear your story again from the start, told in a more systematic fashion, as I'm totally confused about the sequence of events you've gone through.

Anthony

[madmaninshed]

Hi Ashaughnessy, Collected car 2 weeks ago. Battery was flat. Jump started and drove home 80 miles with no probs (and stopped for fuel on the way and it started ok). Trickle charged battery overnight a few times. Did a few short runs checking out other problems with car - again it started ok (if a little slow at turning over). Went for a longer run and drove car fairly hard. Stopped when hot and after 10 mins battery flat. Bump started and drove home about 5 miles in heavy traffic. Trickle charged overnight and battery completely dead. Never notice if ignition light came on or not so far. Bought and fitted new battery. Started car easily. Noticed no ignition light at any time. Trickle charged new battery as conditioner showed one light short of full charge. In morning battery completely flat and charger failed. Recharged new battery out of car with borrowed charger and called in Auto Electrician. He noticed only 4v across ignition lamp but said (apart from the lack of a warning lamp) this would not affect charging. He checked everything out and gave clean bill of health. I did not start or alter anything on the car after he left. I checked the voltage across the battery before going to bed and it looked fine. This morning the battery is completely flat again. The alternator is very close to the exhaust manifold and I had planned to fit a heat shield, but had no time left.

[ashaughnessy]

OK, thanks madman, I think that's a bit clearer now.

 

The fact that a new battery drained to completely flat overnight while the car was idle says you have a drain or short somewhere. I'm not an electrician, but it seems to me you'd have to draw quite a current to discharge a full battery in one night (are you sure it was full? When I've bought new batteries in the past I've had to fill them myself and then charge them - was your new battery absolutely full of electrolyte?)

So assuming the new battery had a good charge, is it possible to attach a current meter to see what current is being drawn while the car is switched off? You'll need to attach another full battery to check this. I'd suggest you'd need something of the order of the current drawn by the headlamps to drain a full battery overnight.

 

So I'd say the alternator and ignition light have nothing to do with this, unless they are the source of the short circuit. Certainly its nothing to do with whether the alternator is charging the battery while driving, as the battery drained while the car was idle. Again, I'm no electrician, but I suspect the ignition light should see a full 12v with the engine not running - if that's correct then there's a current drain somewhere that is using up the other 4 volts. You could work out the size of current drain using ohms law and the wattage of the ignition light, but someone will need to confirm that the ignition light should indeed be seeing 12 volts as I've suggested. I think I'd also confirm, after measuring 4 volts on the ignition light, that the battery shows 12 volts across its terminals.

 

A short circuit that is draining the battery would also explain why the original battery was flat when you bought the car. The behaviour you describe with the original battery would be explained if it had been severely damaged by excessive flattening. It wouldn't reliably hold a charge after that.

 

This may sound like a very silly question - have you left your headlights on??? That would certainly drain a battery overnight.

 

Anthony

[madmaninshed]

Thanks Anthony, No I didn't leave any lights on (promise!). The new battery is almost charged up again, so if I want to measure the current drain on the battery when everything is switched off, any idea how would be best to connect the meter? Please excuse my ignorance. I did notice just a very small spark as I connected the second battery terminal each time. I mentioned this to the electrician and he said it was normal. Despite a text at 8am and a voice message on his mobile at 11am he hasn't got back to me, which is disappointing.

[shn7]

To check the current draw you need to wire you meter in series rather than in parallel (measuring volts). So, disconnect one battery cable and connect an ammeter between the cable and the battery terminal. Note: Some multimeters need the test lead to be plugged into a different hole in the meter.

 

Steve.

Sussex (West) AR

Not forgetting Percy the Polar Bear

[madmaninshed]

Thanks Steve, fully understood.

[madmaninshed]

This will sound really wierd......I changed the position of the lead on the meter to Amps and set it to 10A. I connected the bunch of leads that normally connect to the negative battery terminal together tightly and well away from the terminal. I then connected the meter in series. The reading was 0.06A. I then removed the meter lead that was connecting to the neg battery terminal, and tapped it against the terminal. The meter suddenly jumped up to 4.87A. I tried again and again disconnecting and connecting the meter. Sometimes: 0.06 and sometimes 4.87 with no apparent pattern. It is almost as if a relay is pulling in sometimes but not always.... confused.com!! There is probably a simple explaination

[ashaughnessy]

There might be a simple explanation, but 4.87 amps sounds like the right order of magnitude to drain a battery overnight (someone confirm please?). It might simply be that you didn't have a good solid connection and that as you jiggled the bunch of wires around you sometimes got a good connection (and a 4.87 reading) and sometimes a bad connection (and the 0.06 reading). If you can get a sustained 4.87 reading, this would be the source of your problem but you still need to track down the culprit.

 

I've been thinking about this over lunch and here's my systematic way to confirm the root of your problem, based on o-level physics and ancient car electrical designs. All this does is confirm you have a current drain and uses the fact that you didn't see the ignition light come on when you turned the ignition on with a good battery.

 

One - ensure you have a battery that is known to be reliable. Either double and triple check your new battery, or temporarily disconnect it and replace with a known reliable battery (it doesn't need to be fitted in the car, as we'll just use it for static testing). We'll assume the battery is OK, but if we don't find any other causes of your problem we can revisit this assumption.

 

Two - disconnect the battery entirely and measure the voltage across the terminals. It should be about 12 volts. I don't know by how much it can be less than 12 volts and still be considered functioning, but I don't think its very much.

 

Three - connect the battery up but don't turn the ignition on. A spark while connecting would (to me) suggest a current drain to be worried about - can someone confirm this? Anyway, check the voltage across the battery again once connected up. It should be unchanged. If the voltage has dropped this indicates two things to my naive mind - one, the battery is knacked. A good battery should hold its voltage when a load is applied (I'm pretty sure) and two - there is a current drain. However, a good battery shouldn't drop its voltage even if current is being taken, so assuming the voltage stays the same, go to step 4.

 

Four - turn on the ignition but don't start the engine. Check the battery voltage again, it should still be 12 volts. Then check the voltage on the positive side of the ignition light - I think it should be 12 volts, but you could check this against the wiring diagram - any resistances in series in front of the ignition light would reduce this. Assuming my assumption is correct and the ignition light should see a full 12 volts, then you should see 12 volts when you connect your voltmeter between ignition light positive and earth.

 

Five - still with the ignition on and the engine not running, connect the voltmeter to the ignition light negative (i.e. between ignition light negative and earth). I think you should see zero volts (but can be checked against the wiring diagram to see if there are resistances in series after the ignition light). If I'm correct and you see more than zero volts, it suggests to me that there is a load that is drawing current in series with the ignition light between the light and earth. This would be your short circuit that needs to be traced. Note that if there is a full twelve volts across the ignition light (connect voltmeter between ignition light positive and negative connections) then the ignition light should be shining brightly.

 

We know for a fact (I think) that there is a current drain somewhere, as you have said that your full battery drained overnight while the ignition was turned off and you didn't leave the headlights on. I think its also a fact that with a battery delivering twelve volts you didn't see the ignition light shining when you turned the ignition on without starting the engine, which suggests a resistance in series with the ignition light that is draining current. I wonder if there is a short circuit in the alternator wiring somewhere?

 

The other thing to do is to turn the ignition off and go round the car connecting your voltmeter to various wires in turn and earth to see where there is a voltage that shouldn't be. We know the immobiliser will draw current but you'd expect this to be tiny - you'd have to connect your meter (in current mode) in series between immobiliser and battery to check what current it is drawing.

 

Anthony

[madmaninshed]

The bunch of wires are bolted tightly together with the terminal nut and bolt to ensure good connection. Battery voltage disconnected is 11.92V (and my meter reads low, so it is higher than that). Work has just gone mad so will have to check other figs later. Thanks, Paul.

[Mick Day]

Just to drop something else in here I think you have to investigate the alternator. Some alternators have 3 terminals & some have 2.

 

If 2 then there is a big red wire terminal that goes to the battery +ve terminal & the other terminal goes to 1 side of the ignition light.

 

With 3 terminals the 3rd terminal should be an ignition switched +ve. If this has been jumped from the big red wire (or another always on +ve feed) it will lead to your battery draining.

 

Another point: if the ignition light doesn't light up with the ignition on, & go out when the engine runs, there is a strong possibility that your alternator will not charge.

 

With the ignition off you should at best only be seeing a few milli-amps current draw, anything more means something is draining the battery.

 

Coming back to the ignition light this should be wired so that there is a 12v +ve (ignition switched) to 1 side & the other side goes straight to the alternator. Turn the ignition on & the light should glow as it is now earthed through the alternator. As soon as the engine starts there is now 12v on the other side of the light (from the alternator) & the light goes out.

 

So you need to find out the correct wiring & ensure it is OK. You need a competent auto electrician to look it over if you don’t feel confident yourself. Maybe relocating the alternator to the other side with a Raceline loom is the answer? However doing it yourself is possible if you have the time & patience.

 

Good luck!

 

Edited by - Mick Day on 11 Sep 2008 12:22:04