CLANCY Posted August 7, 2019 Share Posted August 7, 2019 Hi to all I have a problem I wonder if anyone can help.My defender 90 battery is draining overnight,so I thought I would turn everything off, and remove the neg lead.I put a multimeter from neg terminal to neg lead and check fuses.But unfortunately the reading I am getting on the meter is 12.7v the same if i touch the body. Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted August 7, 2019 Share Posted August 7, 2019 Hello, the voltage drop will be minimal. What you need to do is put the meter on Amps (or milli-amps), remove the battery positive lead and then put the meter between the battery positive and the battery positive lead (that is in series completing the circuit). That will tell you the current drain. Then remove each fuse one by one and see what circuit is causing the drain. Cheers Peter Quote Link to comment Share on other sites More sharing options...
CLANCY Posted August 8, 2019 Author Share Posted August 8, 2019 Thank you Peter for your quick reply.I will check this out today? Trevor Quote Link to comment Share on other sites More sharing options...
CLANCY Posted August 8, 2019 Author Share Posted August 8, 2019 Hi not a good day today.Did a test multimeter went out of range,so moved up to a 10amp test with everthing off the draw was 3.2 amps, checked all fuses no change been checking other fuses winch ect as yet no luck? Trevor Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted August 8, 2019 Share Posted August 8, 2019 That's huge! Did you remove ALL the fuses at the same time? Cheers Peter Quote Link to comment Share on other sites More sharing options...
Tanuki Posted August 8, 2019 Share Posted August 8, 2019 3.2Amps @12V means something like 40 Watts of power is going somewhere! That will be making something somewhere rather warm. Try feeling the alternator-casing some hours after the engine's been run to see if it's still noticeably hot - in the past I've seen failed diodes/regulators continue to energise the alternator rotor when the engine's stopped. Quote Link to comment Share on other sites More sharing options...
teabag Posted August 8, 2019 Share Posted August 8, 2019 (edited)  Circuits that are switch controlled are dead so no need to test them, but an iffy alternator with a faulty diode/ regulator will drain a battery overnight, diodes can be tested but the time it takes it’s just as easy fit a new pack. Edited August 8, 2019 by teabag Spelling Quote Link to comment Share on other sites More sharing options...
CLANCY Posted August 9, 2019 Author Share Posted August 9, 2019 Thanks you Guys for the info, I will do some more checks today especially the alternator Trevor Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted August 9, 2019 Share Posted August 9, 2019 Jut pull the plug off the back of the alternator and see if the current drops. Peter 1 Quote Link to comment Share on other sites More sharing options...
CLANCY Posted August 9, 2019 Author Share Posted August 9, 2019 Thanks all Progress at last, removed all alternator leads had another battery check drain just a few milliamps so the problem is there somewhere. but at the moment rain has stopped play. Trevor Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted August 9, 2019 Share Posted August 9, 2019 As others said, with a result like that it'll be something in the regulator pack, likely a diode or two. A lot of alternators you can replace the reg pack quite easily, often in-situ. Quote Link to comment Share on other sites More sharing options...
simonpelly Posted August 9, 2019 Share Posted August 9, 2019 "but at the moment rain has stopped play" - Queue the water ingress threads 🙂 Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 9, 2019 Share Posted August 9, 2019 2 hours ago, FridgeFreezer said: As others said, with a result like that it'll be something in the regulator pack, likely a diode or two. A lot of alternators you can replace the reg pack quite easily, often in-situ. Any idea how easy it is to do the bearings on an alternator? Quote Link to comment Share on other sites More sharing options...
western Posted August 9, 2019 Share Posted August 9, 2019 not easy at all, without a bearing press, much quicker to buy/fit a new or recon alternator & could be used as an excuse to upgrade the rated output i'e' - 65amp for a 100 or 120amp plus increase the wiring diameter from alt to starter/battery. Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 9, 2019 Share Posted August 9, 2019 Thanks, Ralph.  The wiring was done years ago to 100A, but it’s just a 65A alternator and a 100 is the plan.  I was just thinking of keeping the 65 as a spare if I could sort the noisy bearings - it works well and doesn’t have any play, just a bit noisy on the front (I think it’s the bearing rather than the pulley, which looks like new). Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted August 11, 2019 Share Posted August 11, 2019 Only person I've known do alternator bearings is Daan, and that alternator then failed in very short order on the way to a ferry 1 Quote Link to comment Share on other sites More sharing options...
simonb Posted August 12, 2019 Share Posted August 12, 2019 I have done several in the past but as Ralph mentions you need the right pullers. The cost of new ones complete with pulleys has dropped so much now that it is hardly worth the faff. However still willing to do them for forum members if you can get them to me. 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.