 | Home > Puma (Tdci) > Parasitic battery drain query |
 
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| ickle Member Since: 22 Jul 2010 Location: South Vendee Posts: 1785   
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thanks Steve, yes when the ignition is off there is a heavy drain.
It was getting late and I didn't want to mess with disconnecting the alternator in the darks I gave up and decided to ask the wisdom of the forum if there was an easy way to check the alternator? I have pulled literally every fuse and relay with no drop in the parasitic voltage. Keith |
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18th Mar 2024 7:17pm |
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| ickle Member Since: 22 Jul 2010 Location: South Vendee Posts: 1785
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Thanks Steve, Yes I've got good 14 - 14.4v whilst running on the Scangauge
Does the magafuse protect the whole +ve cable? If it does is this not the same as disconnecting the +ve terminal or am I being thick? I've not had interior lights for several years  & had assumed the 10AS has fault, alarm CL etc works well I've just not had time to strip it and send it back to the UK for overhaul.
Also I've pulled the alarm fuse, if there was a water related fault (and we've had massive rain here as well) would that not stop the drain? Thanks again. |
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18th Mar 2024 8:40pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20430 
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If you remove the negative or live battery clamp, the latter should be first off and last on.
Then you are isolating everything, turning everything off, so you’ll get no battery drain at all. If there is water anywhere live that it should not be, with ground near which is common, then that’s how you’ll get drain on the battery as the water will conduct some power to ground, but won’t always blow any fuse as the current draw is often under the fuse or circuit rating anyway. Which is one of those things that are difficult to diagnose unless visually or electrically tracked down. I’m thinking water ingress due to the fact that you are finding it difficult to track down, and coincidentally due to the moisture, wet atmosphere and heavy rain that has been around and land rovers leak commonly. When you say no interior lights, is the wiring still there? If so, it can still be the issue. There is permanent live there, there is also permanent live at the 10AS, the head unit and also to the starter motor. There is also permanent live to the rear behind a speaker panel. Test the head unit live permanent live supply at rest, it should only be under 50mA. (Milliamp Current draw). Tested with a Multimeter in series. (If it’s not then there is a fault). It can be that ignition live and permanent live is the wrong way around also, which can mean the head unit can be on when parked up and drawing current. If this happens it can draw 8 to 14Amps Approx, easily enough to flatten a battery. Has there been anything done with it before this started? Just a possibility, either way, when the ignition is off the head unit should not operate. If it does, then that means it could be left turned on and that means it could flatten the battery. Long shot but you never know, the issue you have will be permanent live related that’s for sure and that’s either a load that shouldn’t be permanently live, a faulty component, incorrect wiring or water. If you haven’t fitted anything before this happened, then it’s probably not incorrect wiring. If you have a tracking device, there could be a fault there. If you find anything wet I’d be very suspicious, especially in seat boxes, fuse boxes, interior light wiring etc. Hopefully some ideas, isolating certain things usually tells you a good indication. If the draw is then cured with an item specifically disconnected then that’s the culprit of the fault. How old is the starter motor? Check for draw at rest on the cable between the starter and battery live. $W33T $0U7H3RN $UG4R 🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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18th Mar 2024 9:20pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17432 
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The megafuse protects the cable to the starter motor and alternator only, not any of the services powered from the BJB. If, as sometimes happens, the rectifier pack in the alternator is breaking down it can cause a drain on the battery with the ignition off, in which case pulling the megafuse is likely to stop it. |
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18th Mar 2024 10:18pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20430
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The biggest pain with that is accessing the connections they can be a bit of a pain to get at.
Here is a bit of info from google on that: What happens when Alternator Rectifier fails. The battery will become depleted, resulting in the car not being able to start. The engine will begin to run rough, lack power and eventually stall and not start again. The battery warning light will turn on, warning you that there is a problem with your alternator charging system. (Or voltage is lower than expected when tested). What causes alternator rectifier to fail? Because of the substantial load handled by the alternator, the rectifier diodes fail because of overheating, overloading or because of poor connection between the alternator output and the battery positive terminal. Leaky or shorted alternator diodes can cause rapid changes in the output voltage of the charging system. Those are a couple of examples, and likely why LR have torque setting for those connections. Defenders being what they are, things coming loose is common though and the battery clamps aren’t the greatest. I tend to see about 0.2v voltage fluctuation either way when running as normal except for brief heavy loads and voltage stays pretty much static at idle. If it significantly rises under either rpm or drops a lot on idle without and specific load then there a sign of poorly performing Alt. Has there been any heavy electrical loads applied? Perhaps the starter motor nuts or alternator nut simply needs tightening. Alternator + : 8NM Battery Live + to Starter + : 12NM Starter to Alt + : 8NM $W33T $0U7H3RN $UG4R 🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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18th Mar 2024 11:11pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17432
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It's relatively easy if you remove the airbox and induction pipework first. Remember however that the large terminal on the alternator is live all the time the battery is connected so be very careful if checking it for security. You can weld a spanner to the frame and set the car of fire long before the megafuse blows. If you end up changing the alternator be aware that one bolt cannot be removed from the alternator bracket with the alternator in situ, so must be unscrewed and lifted out with the alternator. A popular mistake amongst the less gifted tinkerers is to forget to put it back through the bracket before putting the alternator back in situ, then finding that the alternator must be removed again to get the bolt into its hole. I am told this is frustrating!  |
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19th Mar 2024 10:01am |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20430
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Oh yes, I believe in a pinch the battery can be used for welding as well there is more than enough Amps there. (Bush fix type style).
I’d rather not try that to be honest! It does amuse me when people think they can get electrocuted though from 12 to 16v dc.
The sparks that can be produced though certainly make most of us jump though through surprise rather than actual shock as the voltage isn’t enough to achieve anything. The more common area to accidentally short is the live + battery post, it’s highly likely if you work on that without insulated tools and with the ground lead connected on negativethat you’ll make contact by accident probably with the wall of the seat box or battery securing post etc, which is why I always take the ground lead off for anything like that. It’s best really to isolate it when doing most things really, just stick on of those memory saver things in the 12v accessory socket (something I don’t have). Otherwise you then end up having to set up the HU again, Clock and other items and if you’ve got the head unit setting dialled in such as frequency settings. It means that can end up having to all be set up again. $W33T $0U7H3RN $UG4R 🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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19th Mar 2024 3:13pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17432
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Which is of course why you ALWAYS disconnect the negative terminal first on a negative earth vehicle, and the positive first on a positive earth vehicle. In an earlier life I worked for an engineering firm which designed telephone switches (exchanges), powered from -48V dc busbars. I have seen an inept person vapourise a 3/8 BSW OE spanner across the bars. It is sobering what a 48V dc differential powered off a 5000 Amp rectifier bank can actually do. The individual concerned (who was not trained nor authorised to be anywhere near the busbars) was extremely lucky that he had dropped the spanner and was not holding it. It is much more impressive on dc due to the sustained arc you tend to get. It was always interesting making live connections when the humidity was high on such systems since you could feel the electricity flowing up your arm and down to your feet. In dry conditions you were unaware of it since your impedance was greater and connectivity reduced. Watches and jewellery were of course strictly verboten. Happy days! |
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19th Mar 2024 5:55pm |
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| spudfan Member Since: 10 Sep 2007 Location: Co Donegal Posts: 4698 
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Makes you appreciate those poor blokes working up poles in less than ideal conditions. 1982 88" 2.25 diesel
1992 110 200tdi csw -Zikali 2008 110 2.4 tdci csw-Zulu 2011 110 2.4 tdci csw-Masai |
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19th Mar 2024 6:00pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17432
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In Bristol in the 1980s the local "yout" used to take pot shots at the lineys with air rifles. I kid you not.
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19th Mar 2024 6:12pm |
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| spudfan Member Since: 10 Sep 2007 Location: Co Donegal Posts: 4698
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The first to complain when they have no power. 1982 88" 2.25 diesel
1992 110 200tdi csw -Zikali 2008 110 2.4 tdci csw-Zulu 2011 110 2.4 tdci csw-Masai |
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19th Mar 2024 6:55pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20430
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National grid were outside here today, funny enough they had a white Puma cherry picker. (And Transit)
Worked on the power cables live, put some insulating binding on them, something like the spiral wrap like stuff. They ran out of it, so probably will be back. Some of the old wrap was falling off, in places it was gone completely. It was some kind of grey / orange fibrous material, I’d imagine fibreglass, hopefully not asbestos.. On a different HV DC is quite something, not to be trifled with. Nor is HV AC for that matter. At least with automotive there is, WAS, less to be shocked with except ignition coils and spark plugs. It won’t be long before someone will be fried on these new 600v systems no doubt. 
I’d imagine around 50v mark upwards, becomes penetrate to skin that’s dry. What do car ignition coils get up to on petrols? I’d imagine 10kv plus. Typical livestock electric fencers are often 6 to 16kv, of course they are set to pulse which is for safety. $W33T $0U7H3RN $UG4R 🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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19th Mar 2024 7:12pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20430
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Double post* $W33T $0U7H3RN $UG4R
🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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19th Mar 2024 7:12pm |
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| ickle Member Since: 22 Jul 2010 Location: South Vendee Posts: 1785
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Thanks both, I will look again at the weekend & put it up on my ramp (must tidy barn first)
No changes over the last few weeks, new head, turbo & rad etc late last year so there's a chance something come loose. Will check and report back. |
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19th Mar 2024 7:30pm |
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