| [ Total Views: 733 | Total Replies: 9 | Thread Id: 48473 ] |
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 Purple Martin
A.k.a.: Martin
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 posted on January 30th, 2006 at 03:59 PM |
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Current drain flattens battery
I think my beetle has a current drain which flattens the battery, but I'm not sure where the problem is.
The charging system is working: when the motor is running I get 13.9V at the alternator and at the battery, and the alternator warning light works
while starting and then goes out just like it's supposed to.
I then turned the motor off and disconnected the battery negative terminal, and used a multimeter to try and take some readings. This is what I
found:
I tried to measure a current passing between the negative terminal and the negative lead, but it didn't show any.
I measured the resistance too, and got -50ohm (this is probably the stereo???). When I switched the multimeter connections over I expected to get
+50ohm but instead I got a blank reading which I thought was odd.
Where is the current leak likely to be???
1959 red & white Beetle
1975 Kombi camper
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PurpleT3
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| posted on January 30th, 2006 at 04:16 PM |
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With every thing turned off there will be no power demand, thus no current flow. The little bit of power required by the stereo to maintain the
memory is probably too low for your multi meter to read.
Not sure what the -50 Ohm means, you cannot get negative resistance, it does not have polarity like voltage. It is probably just the way your
multimeter displays.
What was it that made you think you had a current drain in the first place, describe the original problem which caused you to start checking.
Ain't nothin' like the wind in your hair.
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Purple Martin
A.k.a.: Martin
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| posted on January 30th, 2006 at 04:47 PM |
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The battery goes flat if I don't drive for a few days! It's a newish NRMA-supplied battery and the weather is very warm, so I doubt if there is a
problem with the battery.
1959 red & white Beetle
1975 Kombi camper
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tassupervee
A.k.a.: Knob Jockey
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| posted on January 30th, 2006 at 06:03 PM |
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Dissconnect your battery +ive
Set your multi-meter to AMPS (not ohms)
Red lead to battery terminal and Black lead to cable.
What does it read now?
Now, is there a glovebox light?
A bonnet light?
An engine lid light?
Interior light?
Unless the battry is buggered, (and just because its newish does not mean it has not fallen over) there should be a significant drain to flatten a
battery in a couple fo days.
Id look at the radio to make sure it is actually turning off.
The next thing is some kind of fault in the alternator/regulator. And the battery is earthing via a short in there but still allowing your alternator
to charge at full voltage.
have fun
L8tr
E
Im not a complete idiot, quite a few parts are missing....
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firefly
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| posted on January 31st, 2006 at 11:04 PM |
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Be careful withg useing you multi meter in amps, as most will have a fuse ciruit and a unfused ciruit. depending on the brand will depend on the max
current the multi meter can coupe with. Sometimes the alternator can develope a short internally, and this will allow the alternator to use the
stored eneregy. To test the battery condition (if it is not sealed) grab a set of wire and use these on the end of your probe, and meter between the
cells. this will tell you whether you have a dead cell. so start with the negitve to teh first cell (ie into the electrolight) this shoudl read 1/6
of the total voltage (ie if battery at 12.3V then one cell (or each cell rather should be approx 2.06V. if all are within each other then the battery
would seem fineish.
Cheers
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Edmond
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| posted on February 1st, 2006 at 12:24 AM |
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Where were you measuring the resistance? You can get those kinds of readings when you accidently measure resistance across a battery. You could also
have a faulty meter.
My guess is a dead cell.
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Purple Martin
A.k.a.: Martin
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| posted on February 3rd, 2006 at 01:00 PM |
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OK I did a bit more measuring today: there is a current drain of about 35mA, which is presumably going to the stereo. I doubt if that is enought to
drain a battery, even in a couple of weeks.
The battery is sealed so I can't test individual cells.
[ Edited on 3-2-06 by Purple Martin ]
1959 red & white Beetle
1975 Kombi camper
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karmen
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| posted on February 3rd, 2006 at 02:05 PM |
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call the nrma
get them to check
i bought a new battery recently and 6 weeks down the track it was dead.
repco replaced it on the spot fitted as even though i bought it at supercheap.
maybe even go to repco purple lol
Karmen
56 oval resto 60 Cal KG
58 & 62 beetle parting. 74 panel parting
63 Baja 80 GLD parting
58 donor split 11 window 63 Splitty sgle cab /son's
96 Seat Cordoba GLX daily drvr.
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Purple Martin
A.k.a.: Martin
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| posted on February 3rd, 2006 at 04:08 PM |
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I might call the NRMA, they supplied the battery! So they can replace it for me for free 
1959 red & white Beetle
1975 Kombi camper
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karmen
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| posted on February 4th, 2006 at 01:15 PM |
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any dealer of that brand will simply barcode it and see the wty tenure and replace for good will.
Karmen
56 oval resto 60 Cal KG
58 & 62 beetle parting. 74 panel parting
63 Baja 80 GLD parting
58 donor split 11 window 63 Splitty sgle cab /son's
96 Seat Cordoba GLX daily drvr.
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