axlechorus Posted March 26, 2010 Share Posted March 26, 2010 Hi all. Having some issues with my discovery 200tdi 1993. Went to turn it on after being left for 3 or 4 days and it was as flat as a pancake with none of the usual culprits left on i.e. the headlights. Only this was the indicator which wouldn’t have kept running once the keys came out the ignition? Either way I had the RAC man out who swiftly revived it and did a few checks. Alternator is fine pushing out about 14.5 amps as when I put it on last Easter but there is a mysterious power drain from the battery when the car is turned off of about 0.5 amps which would explain why the battery which is only a stock sized one was dead after the 3/4 days I left the car. Has anyone had any experience of this, either through fixing a similar fault or ideas about what it could be? At the moment I have disconnected the battery which is ok for now but not something I want to do long term for sure. Thanks in advance. Ryck Quote Link to comment Share on other sites More sharing options...
DrT Posted March 27, 2010 Share Posted March 27, 2010 Why don't you simply put an ammeter in series with the battery output. This should show the apparent 0.5A drain current, or whatever it actually turns out to be. Then pull out each fuse, one at a time, replacing it if you see no change in the reading until you find the circuit which is causing the power drain. Then you can investigate further. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted March 27, 2010 Share Posted March 27, 2010 Could be the alternator regulator too, it may be charging but the diodes may be faulty and draining back when not running. Quote Link to comment Share on other sites More sharing options...
axlechorus Posted March 27, 2010 Author Share Posted March 27, 2010 Cheers DrT - I think I will go down that trial and error route, are there any circults that you would start with? Bogmonster - How would I test that? Discontect the alt at the back and recheck the drain with an ammeter in line as mentioned above? Cheers Quote Link to comment Share on other sites More sharing options...
BogMonster Posted March 27, 2010 Share Posted March 27, 2010 Yes - take battery off, disconnect and insulate alternator cable so it can't short, reconnect battery, check current drain as above. Quote Link to comment Share on other sites More sharing options...
DrT Posted March 27, 2010 Share Posted March 27, 2010 are there any circults that you would start with? I would do as BogMonster says and test the alternator first, if that is okay then it could be anything so trial and error is probably the only way. There aren't too many fuses in the fuse box so it should be fairly quick to identify the circuit if it isn't the alternator. Quote Link to comment Share on other sites More sharing options...
axlechorus Posted April 6, 2010 Author Share Posted April 6, 2010 Hi Guys, just an update and to say thanks for all your help. Turns out that it was the rear load bay light which is obscured by my store box in the back but had been knocked onto on, hence the 0.5 amp or so power drain that was being recorded. Needless to say this light is no more and the power drain is down to 18 milliamps which can be attributed to the clock and all is in order now I have also checked the alternator out and the battery on holding charge in the morning. The alt is good but the battery this morning after yesterdays laning was down to 12.8 volts so I may well looking into a new battery espically for the winter as this one is over 18 months old when I brought the car. Does anyone have any battery recommended batteries for discos? Cheers Ryck Quote Link to comment Share on other sites More sharing options...
pinny Posted April 6, 2010 Share Posted April 6, 2010 12.6 to 12.8 is a fully charged battery my disco charges at 14.2 with nothing on and drops to 13.6/13.8 with lights blower wipers on overnight battery drops to 12.6 chris Quote Link to comment Share on other sites More sharing options...
axlechorus Posted April 8, 2010 Author Share Posted April 8, 2010 Cheers for that, some good news at last then. Looks like that money will be going towards some new wheels and tyres. Many thanks. Ryck Quote Link to comment Share on other sites More sharing options...
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