Battery Issues / Cold Starting

Whilst changing some wiring in the cab two weeks ago I shorted a live wire to the chassis with a screwdriver accidentally. The result was a blown fuse, some smoke and a smell of burning I changed the fuse and didn't think it would be a problem.

After the short I needed to get the jumpleads and start that way as it seemed the battery had completely dumped itself and would barely turn the starter over. With a jump it started fine and after a little run seemed to be behaving.

This was 2 weeks ago, but since the cold weather I am having lots of related problems again.

Firstly, in this really cold weather it seems like there is no longer barely enough 'ooomph' in the battery to start him up initially. Secondly, because it is so cold he hardly ever wants to start first time anyway and so by the time I am on the 2nd or 3rd attempt the battery is barely turning the starter over. If I leave it for some time It seems to slowly recharge itself and have enough ooomph for one more try but again, if not succesful the first time, the second time it is severeley lacking.

I have taken some readings in case it might help complete the picture:

12.75V with engine off after a quick run. This drops by .01 every 10 seconds or so. I watched it drop to 12.69V then left it.

Half hour later it was at 12.48V.

Whilst the engine's running with nothing else on (no lights, heater etc) it shows 13.83V.

I have a number of questions I guess.
1) Should the figure with engine running be 14.4V as per other web sources I've seen or is this close enough? Therefore, do I have an alternator issue??

2) Is it normal that the battery, with engine off (and no other drain on it that I'm aware of), should be decreasing at that rate (if any at all)? Do I have an electrical problem causing this??

3) Should a healthy battery be able to maintain enough power for me to try and start the car 4 or 5 times in short succession with the key held for 5 seconds or so each attempt? Or should I be changing my practice/giving it a rest between or shorter bursts??

4) Is this all a result of me shorting the battery via some wiring in the cab? I thought the fact the fuse burned out almost immediately would have stopped any significant discharge.

5) What is it about cold weather that might mean I need more ooomph than normal from my battery or is it just that cold weather reduces the ooomph from your battery?

6) Lastly, I am getting a spare battery tomorrow from a friend. I was intending to have a dual battery setup so I could run a few things inside and for more ooomph on cold mornings (though I don't know why I need it but hear it helps - see Q5!). With the scenario described here will my current battery still be worth anything to me or is it time to write it off?

Of course, any other info or feedback you feel may be relevant I would love to hear. As well as any relevant ideas for dual battery setups (though I know there is plenty of info on here I will search for when I need to).

Thanks as always!

Andy.

13.8v as a running voltage is just about OK - is this on tickover? Does this rise if you rev the engine? if so this is fine.
The voltage drop with time may be a problem - is there anything connected that runs with the ignition off? If not you may have a short somewhere.
How old is the battery? Sometimes they last for ever but can be buggered in a couple of years.
Yes, it's more difficult to start in the winter. Diesels need more pre-heat, petrols may struggle to start 'cos the fuel won't vaporise, the oil is stiffer so the engine's harder to turn and the batteries don't produce their peak current when cold. (put the lights on for a couple of minutes before starting to warm the battery up)
Try a new battery, clean up the contacts on the high current cables and make sure the timing/injectors/ignition system is spot on and all should be well.

Thanks Oxides, as helpful as ever.

I'll try a borrowed battery tomorrow and see if it helps. The one in there is only a year or so old. Does it sound normal that my shorting it with the screwdriver has created all these issues? Prior to that incident I had not had any battery/starting issues. Although, I guess it could be just as likely that I have shorted something during that bit of work which is constantly draining the battery anyway right?

I'll check the voltage again in the morning and see if it's continued to fall over night and if so check wiring for any shorts.

You're right in saying the fuse should blow before causing damage - but it depends on the size of the fuse! To be fair, fuses are there to protect the wiring only.

Have you checked the electrolyte level? And if you have access to one use a hydrometer to look at the specific gravity.

If the electrolyte is low, top it up with distilled water and stick it on a battery charger overnight and it should hopefully recover from any damage.

It's worth disconnecting the battery and reconnecting via an ammeter to see if there is any drain on the battery.

oxides said:

It's worth disconnecting the battery and reconnecting via an ammeter to see if there is any drain on the battery.

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Just don't try starting it with the ammeter connected unless it's a beefy one! Or unless you can borrow a clip-on ammeter.

TheKeymeister said:

Just don't try starting it with the ammeter connected unless it's a beefy one! Or unless you can borrow a clip-on ammeter.

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Oh yeah - I should have mentioned that. One of the problems with series landys is that a lot of the electrical system is unfused and you really have to be careful poking around behind the dash.
One thought, rather low volts at the battery when running plus continuous discharge could mean a fault in the alternator.

Is the battery fully charged to start with ?
If you are not totally sure then it would be worth giving it a full charge and then see what happens.

So I got another battery from a friends unused swb. Fitted and seems to be charging well from the alternator (over 14v) and holding the charge more than my previous battery 12.5v and possibly more since I haven't given it a proper run yet.

What I have been doing is disconnecting the battery when I'm parking up just because I'm afraid there is a drain on the battery somewhere and I will not be able to start him again. So I think I may as well add an overhaul of the electrics to the HUGE list of Land Rover ToDo's! But must fix my diff, leaking tranmission, broken manifold etc etc first!

I wouldn't go blaming the electrics just yet - sounds as though your old battery was no good somehow. I'd be looking into that first, check water level, specific gravity if you can, and a full long charge.

Keymeister - Ah well, I didn't fully explain the other strange stuff that happened. I put the other battery in (which had stood unused for 12 months) and the car wouldn't start (turned over but wouldn't fire). Very quickly the new (not actually new but new to my car) battery wasn't providing enough welly to turn things over properly. SO, I put the old battery back in and it started the car (it wasn't starting it before I took it out 20 minutes prior). I figured the new battery probably just needed a good charge and it would be fine so with the engine still running I took the old battery out and put the new one back in to let it charge. Since then it has been starting the car fine (though I have been disconnecting the battery whilst engine off to rule out any leccy problems). I thought the leccy might be at fault as the other battery seemed to discharge itself whilst the car was stood, yet when it was disconnected for a while it seemed to recover itself enough to then start the car. I haven't verified the same discharging happens with the new battery as I don't want to take the chance, hence the disconnecting it, because it is my everyday car. however, I will fully charge the old battery (out of the car) and see if it holds it. If it doesn't I will reconnect the new battery whilst the car is stood and see if it still works after a while - prooving perhaps the old battery was dead. If the old battery does hold it's charge though, then I will want to verify there is not something draining the battery on the car prior to leaving the new battery connected with the engine off.

I see they do solar powered trickle chargers. Are these any good? It would be nice to use solar and I guess I could always keep it in the car in case I got stuck on an expedition or something.

Water247 said:

Keymeister - Ah well, I didn't fully explain the other strange stuff that happened. I put the other battery in (which had stood unused for 12 months) and the car wouldn't start (turned over but wouldn't fire). Very quickly the new (not actually new but new to my car) battery wasn't providing enough welly to turn things over properly. SO, I put the old battery back in and it started the car (it wasn't starting it before I took it out 20 minutes prior). I figured the new battery probably just needed a good charge and it would be fine so with the engine still running I took the old battery out and put the new one back in to let it charge. Since then it has been starting the car fine (though I have been disconnecting the battery whilst engine off to rule out any leccy problems). I thought the leccy might be at fault as the other battery seemed to discharge itself whilst the car was stood, yet when it was disconnected for a while it seemed to recover itself enough to then start the car. I haven't verified the same discharging happens with the new battery as I don't want to take the chance, hence the disconnecting it, because it is my everyday car. however, I will fully charge the old battery (out of the car) and see if it holds it. If it doesn't I will reconnect the new battery whilst the car is stood and see if it still works after a while - prooving perhaps the old battery was dead. If the old battery does hold it's charge though, then I will want to verify there is not something draining the battery on the car prior to leaving the new battery connected with the engine off.

I see they do solar powered trickle chargers. Are these any good? It would be nice to use solar and I guess I could always keep it in the car in case I got stuck on an expedition or something.

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Ahh sounds like there could be a drain somewhere then as you say - borrowing a clip-on ammeter would help to trace that.

Wouldnt bother with solar panels, they do get used on canal boats alot but they sit for a long long time, and have alot of roof space for huge panels whereas a Landy doesn't. The small ones with rubber suckers that stick to the window are pretty much useless for the amount of power they give.

I'll give the solar a wide birth then. Guess if I got stuck remotely I'd be better off keeping a starter handle with the vehicle and starting that way.

I've not used an ammeter before but just Googled so thanks for the pointer. I have a multimeter which I'm thinking may do the job??

Water247 said:

I'll give the solar a wide birth then. Guess if I got stuck remotely I'd be better off keeping a starter handle with the vehicle and starting that way.

I've not used an ammeter before but just Googled so thanks for the pointer. I have a multimeter which I'm thinking may do the job??

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A solar panel definitely won't give you enough amps to re-charge it following a failed start anyway.

Bear in mind when using an ammeter that you have to break the circuit to measure the current/amps - as I said if you know anyone who has a clip-on ammeter it'd be easier as you just clamp it over the live cable and it gives a current reading with no messing about disconnecting circuits.

Guess I'll be buying a sparky friend a pint then whilst he educates me on how to use his ammeter

A multimeter will do fine. Make sure the ignition is off and everything is depowered - don't forget any interior lighting - take the live off the battery and connect the +ve battery to the +v current terminal of the meter, switch it to DC current, and the -ve of the meter to the battery cable. There should be no current flowing at all.

Oxides,

I broke the circuit with the multimeter and got a reading of .091 amps so I guess I have a short somewhere. This seems like a piddly amount of current, though I guess if it is flowing constantly then it would have been enough to explain my issues? Should the expected reading really be 0? I mean, should I expect to see even a tiny current for whatever reason (ambient loss of electricity or something - I dunno !!) or am I truly aiming for all the zeros?

Water247 said:

Oxides,

I broke the circuit with the multimeter and got a reading of .091 amps so I guess I have a short somewhere. This seems like a piddly amount of current, though I guess if it is flowing constantly then it would have been enough to explain my issues? Should the expected reading really be 0? I mean, should I expect to see even a tiny current for whatever reason (ambient loss of electricity or something - I dunno !!) or am I truly aiming for all the zeros?

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I'm not sure if there's any leakage current through the alternator - I'll have to go and measure it. 90mA sounds a bit high - do you have anything that needs a standby current like a radio?

Yes I do have a radio which I guess will be using something for its memory. Though I would expect that to be so minute that it could not be responsible for my flat battery issues. I re-measured the current with the radio on and it showed .5 amps. So the memory on the radio using .09 (just under a fifth) seems to be a little high to me.

What do you think??

I would love some clarifiaction/confirmation of my thoughts...

My S3 'could' be started with a handle, I also know from experimentation that it runs just fine if I disconnect the battery once it's running. Is this because (other than lights and perhaps other non-critical components) everything is mechnical? I suspect disconnecting a battery on a running modern day car would make it stall as the ECU would fail and other critical components (e.g. fuel pump) would be electric and therefore also fail to work.

I thought once any engine (including my S3) was running it required a constant(ish) spark to keep combustion going and the engine ticking over. So how does my S3 still run with no battery connected?

Just when I think I begin to understand things I start writing about them and realise I am more confused than ever

Thanks,

Andy.