Battery goes flat.

[John77]

Fuse 62 diagnostic socket and fuse 64 radio / nav....
Diagnostic socket not fitted with one of those bluetooth readers for monitoring engine is it ? as these will quickly kill a battery as it will be constantly on and with the radio/ nav is that also possibly searching to pair with a phone ?.

Not that I know of. It is just crazy that a fully charged conditioned battery can go totally flat, so that it will not even open the doors in 4 days of not being used. If Television was still on here, I am sure that he could solve this in a short time, but he did seem to be an electronics wizard. Malcolm was one of the main contributors to this forum and is sadly missed.

 

[Blobcat]

Not that I know of. It is just crazy that a fully charged conditioned battery can go totally flat, so that it will not even open the doors in 4 days of not being used. If Television was still on here, I am sure that he could solve this in a short time, but he did seem to be an electronics wizard. Malcolm was one of the main contributors to this forum and is sadly missed.

If you've a faulty diode in the regulator pack on your alternator it can flatten it overnight - it can also be intermittent depending upon where the alternator stops...

 

[John77]

If you've a faulty diode in the regulator pack on your alternator it can flatten it overnight - it can also be intermittent depending upon where the alternator stops...

Thank you and is there a way for a DIY test for that? I think that I may have to take it to a garage to get this solved.

 

[Blobcat]

Thank you and is there a way for a DIY test for that? I think that I may have to take it to a garage to get this solved.

I’d get the alternator off and take it to a specialist for testing / refurb.

 

[John77]

I’d get the alternator off and take it to a specialist for testing / refurb.

Called in at my local vehicle electrics specialists. I have taken alternators there over the years. They are fully booked up until September, when I will book it in. Anyway he told me the things that normally cause these problems on a Mercedes. First radio, etc, etc. I asked him about the alternator diode and he said yes it could be that and a way to test that is to connect a fully charged battery on the car. Do not run it, but leave it for3-4 hours and then feel the alternator. If there is a diode problem the alternator will feel warm or hot as it is drawing power from the battery. So that is the next option and also to check the rear fuse box, which I have not got around to yet. So we will see.

 

[John77]

Well having spent a few days trying to find the problem. See my post Crackle from the Battery. I eventually found, that on taking the fuse out of the Antenna Booster, the battery does not crackle on being reconnected and the car has been sat for 2 days now with a fully charged battery connected and it is still fully charged, which is looking good as it was going totally flat on 2-3 days. It seems that the signal booster or something connected to it was causing the battery to go flat. The next thing is to look at the Booster, Radio and antenna connectors/ Cables to see if it is one of these or the actual booster.