plook

New Member
I seem to be having my annual battery problems on my D90 TDi 1994. I teste dthe alternater yesterday and the output is perfect, checked and cleaned terminals on starter motor but my battery is drained this morning. It could be the starter motor or it could just be a knackered battery, which i am about to try and get tested in Halfords down the road. Last year someone suggested i not get oen of those fancy and expensive batteries with the yellow or red top and that i should get a tractor battery instead. Can someone please give me details on a good strong battery to put in there, oh and if the starter motor is the problem - anyone got a decent used one. I'm in Sheffield.
 
Check that your alternator doesn't have a 'leaking' diode. That could be the cause of your battery not keeping it's charge.

OSD
 
Just had the alternator and battery tested and the alternator is fine and the battery is dead, it's down to 24%, so i am looking to replace with a good strong one. The dead one is a 690 amp Banner, so any suggestions for a good replacement would be great.
 
I'd just get the standard battery (072 - 70Ah 550CCA?????) with a 3-5 year warranty, and keep the receipt!!!!!.

No need to break the bank on an Optima Yellow/Red top (unless you're running a big ICE/Neon/gaming system or something off your Landy? :))

By all means go for a bigger battery (both figures must be at least as high, no point getting 700CCA but less than 70Ah), but if all is fairly normal, then no need.

If you ever leave your Landy for more than maybe 2 weeks without starting it, make sure battery is fully charged and disconnect. Shoudln't store battery empty so I was told....by some clever bloke, so it must be right, or bull****. either way...good luck!
 
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Know you need to find what is draining it, but a solar (they work in daylight not just full sun) trickle charger might help keep on top of it
 
Yes, there must be a drain, or i just killed the battery in the early stages by not waiting for the 'coil' light to go out. In my 1994 Defender there is not a coil lamp, but a choke symbol and i read that there was no need to wait for it to go off. Obviously starting was an issue in the cold until i was told that choke symbol is the coil symbol. How to find the drain if there is one though.
 
I dont think that not waiting for the light to go out woudl kill the battery. The starter draws so many amps, turning over with the heaters still on is a trivial extra. If you want to find out if the battery you buy or the wiring ius at fault, then disconnect the battery when you leave it. If the battery is dead after a spell of being left, it is the problem. If the disconnected battery is Ok, but it is dead if left connected, then you have a drain. No need to disconnect both, the earth side is enough. Then if you have a drain you can use a meter across each fuse position to see what is drawing current when the battery is connected and everything is switched off. A fuse may serve several items but at least you can narrow your search down.
 
If this is an "annual" problem, my guess is you've got some higher-than-average parasitic draw off the battery that combines with some slightly colder weather (which batteries hate anyway) and hey-presto, dead batteries a go-go every autumn.

If that's the case, it doesn't matter how good/big/expensive the battery you put in is, eventually, the long slow draw of current will kill it, especially in cold weather. Especially if you're not using the vehicle regularly for journeys long enough for the alternator to top-up what you take out during a start.

As others have noted, disconnecting the battery during periods of idle is a good safeguard - but a bit of a pain in the ar*e to do. Regardless of that, you want to check there's not a more fundamental problem....

1. Get an ammeter. (Or probably more easy to find these days, a multimeter with ammeter function)
2. Read the instructions on how to measure current.
3. Turn everything off. Interior lights, radio, engine (especially!), ignition.
4. If you've got any immobiliser or stereo that responds poorly to the battery being disconnected (and those alone may be your problem) - make sure you know how to re-set them BEFORE '5'.
5. Disconnect the NEGATIVE terminal strap from the battery. (You could do the positive but no point risking death at this point by inadvertently shorting yourself or the battery through the negative-earth chassis)
6. Carefully use the ammeter to probe the current flow between the negative strap you just removed and the negative battery terminal.
7. This will indicate if you've got an unexpected current draw somewhere.
8. If you have (and the clock - which is the only thing I have running - won't be significant) it's then a question of popping fuses from the fuse-box (or any auxiliary circuit created straight off the battery) to isolate which circuit's got something on it drawing the current.

If you can't find a fault - or you do find it but then more likely can't spend the hours it could take to isolate a problem on any one specific fused circuit - at least you'll know disconnecting the battery between uses is a solution.

I've just replaced the battery in my 90 (thanks to Station House for the advice on the solar unit - I've not got one yet!). That was just old and dying rather than having a specific problem - but I have seen the long, slow, cold weather death on other vehicles. So after the new battery, I've taken to pulling the permanent live out of the bullet connector used for my stereo to reduce the standing draw to just the clock. That's a bit easier for me as it has a slightly "al fresco" installation (it sits in a chassis on top of the dashboard).
 
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Thanks very much for these suggestions. I will get a solar trickle charger and i will follow that brilliant advice on diagnosing the current draw. I do have a multimetre, but not surte without looking at the manual to ee if it reads current. Really appreciate this advice. Will let you know how i get on. I still need to replace the battery, what should i get, the one suggested above?
 
You could get a good idea of any drain by checking the resistance between the disconnected earth lead and the battery. Ideally it should be more than 10,000 Ohms.

OSD
 
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How old is the battery?........They don't last indefinately, sadly.

My Optima red top lasted 6 1/2 years before it started to fail, it would struggle to turn the engine over after a few days inactivity or on a really cold morning, the alternator was ok so I replaced the battery (another red top). All is fine now.

If you've got a standard battery and its over 3 years old my guess would be its probably on the way out.
 
Just did a test between battery Positive (with lead disconnected) to fuse box. Nearly everything in there lights up the bulb in my test probe. Is that normal?
 
So there's current running through majority of the circuits ?

That doesn't sound normal - but if that's the case, would explain the rapidly killed off battery. Although if that was your 90's "normal" state, I'd expect it to be eating one battery a week, not one a year.

If you're testing direct to the fuse box from the positive terminal, are you sure you're not just completing a circuit through a negative earth contact? (Apologies if I'm stating/patronising the bleedin' obvious)

If the test method is good, I'm afraid I'm stumped - as a current leakage en-masse would suggest some larger fault I can't think of.

Someone who knows better (proper) will be along in a minute I'm sure....
 
Test probe? What sort of test probe? There are so many devices available now I cannot be sure what you were using but it sounds to me more like it was test continuity or something. You said you got a light with the lead disconnected so it must be because it would not be detecting voltage, and you would like to think there was power to your fusebox.

To be honest, you are wasting your time doing anything until you have measured current draw with engine and all electrics off and in the locked/alarmed condition.

Get your multimeter, look for A and beside it a solid line and a dashed line below it, this indicates Amps DC - most multimeters will do amps DC.

Now to select a value, the meter will probably have a fused and unfused setting, if you really have no clue what the reading might be and suspect it will be quite low then always use the fused values - worst case here is you blow the 1penny internal fuse, if you misjudge something and you fire over 10amps through the unfused setting, chances are you will need a new meter. I am positive your draw will be less than 10amps, but it could be higher than 200mA and could blow the fuse, so turn it to the biggest value - 10A I expect. Pull one of the leads off the battery, say positive, and put the red lead to the POS terminal and the black lead to the positive cable clamp - ALL the vehicles electrics are now running via your multimeter - so don't turn things on!

Now you need to recreate the condition that is you leaving it overnight, does it have an alarm; late 1994 300tdi model? if so, hold down the bonnet switch if it has one, and lock the vehicle and set the alarm (this operation will still be within 10amps). It will settle down and should draw less than 30mA.

My 300tdi Discovery draws about 25mA in the locked/alarmed position - so every 40 hours it's used 1Ah from the battery or 8.4Ah every 14 days... Which the 85Ah battery copes with no problem - although, I wouldn't like to leave it alone for 3 months or anything!

Now - say you get a large reading, you now want to work out what it could be, if it was the alarm for example, it should go away when you unlock/alarm it. If not then it is something else, now keeping the meter connected (someone to look at the screen for you might help now) I would go into the fusebox and pull fuses for things like the radio, lighting circuits (dodgy relays can sap power) everything really untill with any luck the parasitic load drops off.

Try all that first and see how you get on.
 
Thanks for those brilliant replies and advice. What i meant by test probe was one of those screwdrivers with a lamp in it and a wire with crocodile clip at the end. I removed the + battery lead from the battery and attached the clip of the probe to the positive on the battery and then touched each fuse and most of them lit up the lamp, but as someone said, that is probably just completing a circuit.

Another thing i did was attach my multimetre to the battery unconnected and it was reading 11.9v first thing yesterday morning. I connected the battery and in turn pulled all the fuses and the voltage reading did not change.

I didn't do a Amp reading because i was worried about killing my multimetre but i just checked the manual and it says DC Current range 40mA to 10A. It says it has overload protection fuses in it - 16A (500v) fast blow.

I had the battery tested at Halfords last week and they said it was beyond salvage, down to 23% or so, so i need a new one which i'll get today and then start the Amp testing.
 
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I had the battery tested at Halfords last week and they said it was beyond salvage, down to 23% or so, so i need a new one which i'll get today and then start the Amp testing.

those screwdriver type testers are fairly pointless

wouldn't even bother taking any current readings as am positive a new battery will sort you out
 
...I connected the battery and in turn pulled all the fuses and the voltage reading did not change.

I didn't do a Amp reading because i was worried about killing my multimetre but i just checked the manual and it says DC Current range 40mA to 10A. It says it has overload protection fuses in it - 16A (500v) fast blow.

Careful here, voltage and amps are quite different, we are really only interest in amps for this investigation.

You will be fine with that multimeter as long as you don't start turning lots of things on; there really is no chance that meter will blow when the engine and electrics are all off even if you put something like the headlights on it would be ok (not motors though, they tend to draw a large current on start up and may pop the fast blow fuse).

I would fit the new battery, but before you connect the leads up properly, do the current check.
 

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