Andy_LR90 Posted May 31, 2008 Share Posted May 31, 2008 My 90 has been playing up and I've had the battery on charge overnight. When cranking it over this morning I thought I could smell burning and on checking inside...........I found ..the earth cable, which is a length of braded cable not insulated but it was burning / melting it's way into the battery casing. Is this ammount of heat normal and is it just that I need an insulated earth. Or is my starter drawing far too much current? Ideas, suggestions please? Quote Link to comment Share on other sites More sharing options...
disco_al Posted May 31, 2008 Share Posted May 31, 2008 sounds like something is drawing excessive current to me. best check all the earth points Quote Link to comment Share on other sites More sharing options...
Kim Horsevad Posted May 31, 2008 Share Posted May 31, 2008 My 90 has been playing up and I've had the battery on charge overnight. When cranking it over this morning I thought I could smell burning and on checking inside...........I found ..the earth cable, which is a length of braded cable not insulated but it was burning / melting it's way into the battery casing.Is this ammount of heat normal and is it just that I need an insulated earth. Or is my starter drawing far too much current? Ideas, suggestions please? You probably have a short somewhere. I dont think it is the starter; but you can test it this way: Switch everything electric off, unbolt the earth cable and measure the current between the negative post on the battery and the earth cable. A better idea, if availble, would be to use a clamp on amp-meter. Otherwise you might want to start the measuring with a simple 12 volt lamp - as a multi-meter normally wouldnt like big amounts of current going through it. If the current flow between the battery negative and the earth cable is anything more than a few milli-amps,then you have a short circut somewhere - probably in an unfused connection. That narrows to cables running to and from alternator and starter. Quote Link to comment Share on other sites More sharing options...
Andy_LR90 Posted June 2, 2008 Author Share Posted June 2, 2008 You probably have a short somewhere. I dont think it is the starter; but you can test it this way: Switch everything electric off, unbolt the earth cable and measure the current between the negative post on the battery and the earth cable. A better idea, if availble, would be to use a clamp on amp-meter. Otherwise you might want to start the measuring with a simple 12 volt lamp - as a multi-meter normally wouldnt like big amounts of current going through it.If the current flow between the battery negative and the earth cable is anything more than a few milli-amps,then you have a short circut somewhere - probably in an unfused connection. That narrows to cables running to and from alternator and starter. Tested the current as above and I had .57 amps with nothing on, found it to be the 12V lighter socket, so pulled the fuse on that and no current draw with everything off, so do you think I have a short on this circuit then? BTW 1986 2.5 petrol 90 with LPG Quote Link to comment Share on other sites More sharing options...
DaveSIIA Posted June 2, 2008 Share Posted June 2, 2008 The low (0.57A) current draw won't be enough to heat the cable - it's ~6.8W. There will most likely be a poor connection (higher resistance) somewhere on the earth wiring. High current while cranking will generate a lot of heat through a poor connection and this will be conducted into the braid. If so, you should be able to measure a voltage drop between the battery post (directly on the battery) and the earth strap, or between the earth strap and the chassis / engine block to identify which end is at fault. From the description, it will be the battery terminal end. Clean the contact areas and protect with battery terminal grease. Quote Link to comment Share on other sites More sharing options...
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