A quick question

How can I check for battery drain?? got a good battery on me disco, and 13.7 + volts on the alternator yet battery dont like the cold

Its got an alarm on it but surley this shouldn't drain it. Only used it yesterday evening. just been to it to make sure its ok for morning and its flat as a pancake

how old is the battery, most batteries are only good fer about 3 years, if its older than that i would consider changing it now, cold weather is always a good battery tester

Changed it this time last year cos of same problem

connect yer multimeter on the amps range in series with the +ve terminal of yer battery, with everything turned off. If it shows more than about 0.1A, you've got a problem.

Looks like I am getting cold tomorrow then. Has anyone a wiring diagram for a disco 200tdi???

I can give you copy from rave for classic RR if i knew how to do it!
if that would help
seems like diode at back of alternator is shot

If the battery is not the sealed type buy a hydrometer, charge battery overnight and then draw water from each cell and take the reading from the float. Don't get all anal about the readings and start correcting for temp ect just look for a, a cell that has a significanly lower reading than the rest and b, try drawing the water into the hydometer and squirt it back again a few times, if the water starts to go black and has a lot of what appears to be carbon flakes then the battery is scrap. If you do not have a volt meter take an ordinary 12 volt sidelight bulb and disconnect the pos battery lead and put the bulb between the battery + and lead. If current is flowing then the bulb will glow. Do not forget to disconnect the clock as this will make the bulb glow giving a false reading. Now with the glowing bulb go around pulling fuses until the bulb goes out. This will not show up a faulty diode in the alternator as the battery will discharge into the alt however, a fully charged good battery when connected will make the alternator 'heat up' after about 30 minutes (ignition off) as the load flows back through the windings. Hope that helps.

regards

Dave