Battery drain

Hi, having some problems with the disco starting in a morning. When I go out to start it up it turns over a few times then dies and wont start. fitted brand new bosch battery, seems worse the solder the weather is. With ignition off i can read 12.46v from battery, with engine running and lights and blower on reads 13.78 at the battery and 13.81 if i connect the negative of the volt meter to the engine. one thing I have noticed is that the switched live to the radio doesnt die immediatly as the ignition is switched off, is dies slowly (about a volt a minute roughly). could this be connected to something thats causing the drain?

Its a 1995 300tdi auto

check the connections on all of the large diameter cables connected to the battery, chassis and starter

ignore the radio dying slowly

the connections seem ok.. I have disconnected the battery for tonight. What i did notice is when the ignition is off, i can hear a faint high pitched buzzing sound from the alternator. this stopped as soon as the battery was disconnected. could this be the cause of the problem?

shaunm41 said:

the connections seem ok.. I have disconnected the battery for tonight. What i did notice is when the ignition is off, i can hear a faint high pitched buzzing sound from the alternator. this stopped as soon as the battery was disconnected. could this be the cause of the problem?

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Yes???

redhand said:

Yes???

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Is it an alternator fault? also will disconnecting the battery over night affect anything?