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Disco Battery discharging

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A rather long story.

I have Disco 2 TD5 XS 2002 model and I have had a problem with the battery discharging fairly quickly. I have measured the voltage drop to be .3 volts per day which means that if the battery is not being topped up it will probably be flat after about a week. As I don’t drive the vehicle every week so it is connected to a Ctek charger all of the time. I do however want to get to the bottom of the discharging.

The battery was replaced with LR spec battery last August and it should be OK.

I have disconnected the charger to do the following.

I have over the last few weeks slowly disconnected all the aftermarket electrical fittings one at a time and measured the battery voltage drop over time to see if any of these were the culprit. I have also disconnected alternator and left it for a few days. In this way I have tried to eliminate the cause of the problem. I have obviously topped up the battery with the charger between tests. I have also had an auto electrician look at the vehicle and he did not find anything out of the ordinary – current draw on the battery is about 400ma with the vehicle. I still have the problem and it is till dicharging a tthe same rate.

What else can I do to investigate further – Are there any particular areas to look at on this vehicle that can cause problems.

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A rather long story.

I have Disco 2 TD5 XS 2002 model and I have had a problem with the battery discharging fairly quickly. I have measured the voltage drop to be .3 volts per day which means that if the battery is not being topped up it will probably be flat after about a week. As I don’t drive the vehicle every week so it is connected to a Ctek charger all of the time. I do however want to get to the bottom of the discharging.

The battery was replaced with LR spec battery last August and it should be OK.

I have disconnected the charger to do the following.

I have over the last few weeks slowly disconnected all the aftermarket electrical fittings one at a time and measured the battery voltage drop over time to see if any of these were the culprit. I have also disconnected alternator and left it for a few days. In this way I have tried to eliminate the cause of the problem. I have obviously topped up the battery with the charger between tests. I have also had an auto electrician look at the vehicle and he did not find anything out of the ordinary – current draw on the battery is about 400ma with the vehicle. I still have the problem and it is till dicharging a tthe same rate.

What else can I do to investigate further – Are there any particular areas to look at on this vehicle that can cause problems.

take the battery out. Check the voltage. leave it disconnected from charger etc for a week and then recheck

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The only thing that I can think of is "do you have an immobiliser"?

It maybe worth finding out if there is a way of disabling that for a couple of days and trying your voltage measurment test again.

It is not unusual for a battery to 'leak' charge over a period of time, but a week does seem rather quick.

I did once hook up a cigarette lighter socket to a car battery and modified a battery charger so that the charger could be plugged into the car without opening the bonnet so that the battery could be float charged while the car was not in use. This was for 'over wintering' of an old sports car,......something worth considering as a last resort.

HTH

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Have you got air bag suspension or any of the self levelling stuff?

That's normally a reason for quick flattening of a battery, if it has a slight leak then it tries to correct itself every x number of minutes. This won't show up on the Electricians Test but will flatten the battery.

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I do have Air suspension and I have heard the compressor run but only if I have unlocked woken up the vehicle by unlocking it and opening and closing a door. This does not mean that it doesn't run in the middle of the night when no one is around, I would have thought that the SLS would shut down once the vehicle has been off and locked for a while. does anyone know if it does go into Slumber mode after a period of time?

I do leave the vehicle permanently on the Ctek charger normally but I want to find the cause of the battery drain.

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I have also had an auto electrician look at the vehicle and he did not find anything out of the ordinary – current draw on the battery is about 400ma with the vehicle. I still have the problem and it is till dicharging a tthe same rate.

That is your problem then....

I am not sure what drain my D2 puts on the battery but 400ma or 0.4 amps sounds way too much and is more than enough to drain a battery down over a week or so - most vehicles I have ever needed to look at have been more like about 20ma for powering radio memories etc when everything is working properly. Remember that is 9.6Ah per day so after a week you are down by nearly 70Ah which is about the full capacity of an 072 battery, even the larger Td5 batteries which are 110Ah will be pretty flat by that stage and after ten days they will be completely dead. My D2 gets very little use now and has not been used for nearly a month and even before that only about once a week for a fairly short run, and while I have the battery on charge at the moment to top it up it was by no means flat.

The best thing to do is get a 10 amp multimeter disconnect the battery lead and route it through the meter (don't switch the ignition on!) and then pull out all the fuses or disconnect accessories one by one till the drain disappears, this will tell you what circuit the problem is with. Alternatively you can pull everything out to start with, and then reconnect circuits one by one and see when the drain pops up. One possibility is that something like the alarm or BCU is not "going to sleep properly" - this is a problem in Discovery 3's when somebody leaves the key in the ignition the battery will go flat quite quickly as all the systems stay "on" until the key is removed, though this shouldn't affect a D2. You should be able to narrow it down by pulling fuses to isolate individual circuits though.

One D2 vehicle we once had in at work with a similar fault was traced to a mashed wire behind the radio head unit which was shorting to ground but as it was a poor connection it was only drawing about 2 amps - battery would go flat within 2 days on that one, lucky it didn't cause a fire but the drain was not enough to blow the fuse! I doubt it will be that as it was down to a poorly installed radio on that particular vehicle.

My experience of air suspension suggests that it does not flatten the battery on a D2, it does try and self-level every so often but what happens is that if there is an air leak, the reservoir empties and the suspension goes flat, it doesn't run the compressor to charge the pressure up again until the engine is running.

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I think Bogmonster is right, 0.4amps is a lot and should probably be investigated first, I read about the air suspension on another forum, will try and find a link but based on Bogmosters comments I think it's probably a dead end

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Just checked my D2 and that (2002 D2 V8 auto, no SLS or ACE, alarm and immobiliser fitted but alarm not armed as it is in the garage) draws 0.02 to 0.03 amps (20-30ma) on the 10A scale of my multimeter when at rest, which is about what I would expect. So a drain of 400ma or twenty times that, is the reason your battery is going flat :)

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I know it's not the real fix, but those quick-release battery clamps are useful. We have a client with a DI V8 which regularly flattens the main battery over a week. As he doesn't use the Disco every day, it is a quick job with no spanners to disconnect the batteries.

They also come in handy when your wiring loom catches fire :)

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I will try the fuse removal method and see if I ca narrow the problem down to a specific area. Are there any fuses I should not pull as I do not want to end up having to go to the dealers to have something reset that I pulled the fuse on :huh:

If there is a small short with a were touching earth will this show as current draw when measuring the current draw on the positive terminal with Multimeter?

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You are probably OK pulling any fuses with the ignition off but I would leave the airbag related ones till last.

If you have a 400ma current drain you should be able to see that drop to 20-30ma when you find the circuit with the problem, yes if there is a "leak" somewhere then it should show up.

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Thanks for all the useful contributions so far. I will report back as soon as I have found out which the circuit is the offending one.

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We have a similar problem. I'm not sure mine goes flat in a week, it's closer to a fortnight, but still too soon in my opinion. I leave it hooked up to a charger on a timer. Since mine isn't a daily driver it's not an issue but now I think I'll give a go at figuring out the rate of discharge.......

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Or you can use an 'intelligent' charger like a CTEK. You can leave it connected and switched on for ever with no harm to your battery, the opposite in fact as it keeps the battery perfectly charged. Saves lots of money in scrap batteries in the long run. Ideal for those who only use their Landys for occasional bush trips.

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My little Maypole auto charger has a "trickle charge" mode which holds the battery at about 12.85v according to my multimeter. It was less than £20.

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Or you can use an 'intelligent' charger like a CTEK. You can leave it connected and switched on for ever with no harm to your battery, the opposite in fact as it keeps the battery perfectly charged. Saves lots of money in scrap batteries in the long run. Ideal for those who only use their Landys for occasional bush trips.

As mentioned earlier I do have a Ctek charger and leave it connected. But that is not a solution to my problem only a way to make sure the battery is not ruined. :blink:

I am concerned about going to the bush and then have the drain problem suddenly become serious and result in an unhappy trip.

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A good auto electrician who knows Land Rovers is Frank Copping of Mobilectric in Sundowner close to Northgate. 011 794 1058

This is if you can't fix it yourself .....

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Have you fitted any aftermarket accessories or an additional powerpoint in the rear. I have known of 2 instances where things have been wired via relays where the feed to the relay switch was not ignition sensitive meaning that the relay continued to draw current even when the vehicle was not used.

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Have you fitted any aftermarket accessories or an additional powerpoint in the rear. I have known of 2 instances where things have been wired via relays where the feed to the relay switch was not ignition sensitive meaning that the relay continued to draw current even when the vehicle was not used.

I do have some but I have disconnected everything to do testing so it is not an aftermarket fitment problem.

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Guest DiscoTD4

mmm, this sounds like a tricky one.

By my reckoning 400ma equates to a 5w load assuming 12.5v terminal voltage. The same as say leaving the interior light switched on all the time, so as already confirmed will flatten the battery in no time and potentialy generate a bit of heat depending on where the fault is - ever held onto a 5w bulb - surprising how hot it is!

With the ignition off, I'd assume all the ECU's and electronic stuff is going to be isolated, so what else do we have that potentialy outside the control of the ignition switch:

Some more suggestions:

----------------------------

Faulty alarm unit

A 'whisker' piece of wire shorting to ground - any wiring modifications done, any dodgey looking PVC tape covered joints ?

Does it have A/C ? if so, faulty electric assister fans - assuming they run independent of the ignition. eg, even after switch off are they designed to run on for a while. Cant say I've noticed on mine, but hopefully someone could confirm.

Accessory sockets ? crud in the bottom shorting the center pole to the earth side

Faulty rectifier stack in the alternator eg, short circuited diode (had that on an old Cortina once, but I think the clue was the red charging light was on even with ignition off)

Glove box light - does this work with ignition off ?

Puddle lights on doors - do you have those ?

Faulty after market head unit/radio/CD disc changer/amplifier wired to bypass ignition

Faulty door locking solenoid

Got to dash, I'll have a think and add to the list

Good luck & please keep us informed of progress

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Hi Renq, I see that you are from Gauteng, reason for my remark is that many Gauteng vehicles are forcibly equipped with after market tracker system, the insurance companies likes these goodies.

Now my story: My Discovery's battery started running down, within one-and-a-half day, a lot of testing and eventually it was found to be the tracking device. They have their built-in batteries, but when the built-in battery fails, they tap the vehicles battery, but the vehicle system is too rough and eventually messes the tracking system up. I had mine removed, and that cured the problem. These tracking systems needs to be checked annually, or they can cause battery havoc.

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Who in their right mind would steal a Disco anyway? :D

I have immobilisers etc fitted to keep the insurance happy, and then disconnect them. If the car does get stolen it will be the robbers who did it, of course.

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Who in their right mind would steal a Disco anyway? :D

I have immobilisers etc fitted to keep the insurance happy, and then disconnect them. If the car does get stolen it will be the robbers who did it, of course.

Jim, apparently not so rare, if you recall the spate of 4x4 hijacking/thefts in game reserves on the Mosamiquan border, many were Land Rovers, I admit, I do not know what models. :unsure:

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AFAIK remember there was one Defender hijacked there in all this time. It was, strangely enough, an old V8 that wasn't worth much. I met the guy, he was selling his workshop manual and a few parts. Maybe I don't listen to these stories much, most of them are just that.

And with the downturn of the economy, I reckon a lot of people who can't afford the repayments on their vehicles will suddenly have them 'hijacked' rather than repossessed.

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I had problem with a flat battery and tried eveything i could think of and never got to the bottem of it, then one night the wife says 'whats that funny faint red light i can see in the back door cap, could not find out why but the door warning light was just on, took the buld out and it cured the problem. Good old prince of darkness.

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