OP
OP
Bellow
Hardcore MB Enthusiast
Nope. Fob operated remote locking is as sophisticated as it gets. No other security (bar the ability (currently disabled) to enter a security code for the radio cassette player).
Battery drain - cause?
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Nope. Fob operated remote locking is as sophisticated as it gets. No other security (bar the ability (currently disabled) to enter a security code for the radio cassette player).
OP
OP
Bellow
Hardcore MB Enthusiast
Maybe this is simpler than I thought.
With the MM as ammeter connected across the battery terminals (with both battery leads disconnected) the 0.25 Amp draw shows. Is this how all batteries behave?
With the MM as ammeter connected across the battery terminals (with both battery leads disconnected) the 0.25 Amp draw shows. Is this how all batteries behave?
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Are you connecting the battery in series with the meter to use it as an ammeter by disconnecting one of the leads?
OP
OP
Bellow
Hardcore MB Enthusiast
For all the previous testing yes.
But, when I could read 0.25A on the fuse box end of the solid unbroken wire between the battery and earth and then directly across the battery terminals, it appears I've been chasing this 0.25A (and finding it everywhere) all over the car when it is actually generated at the battery.
So now I need to know is this a function of a healthy battery or indicative of a faulty one.
I do have another battery here which behaves exactly the same. But as it is currently out of its car to be recharged after going flat over a fortnight, I can't be sure it is healthy.
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Things is there will be very little resistance across the leads of the ammeter.
Think of it like an old fashioned coil with a needle, there is little resistance which allows the current to flow through and give you the reading. You can't connect these in parallel as an ammeter needs to go in series to get the reading.
If things were pointing to the radio etc. couldn't you just disconnect this and see if it is this that is causing the drain?
OP
OP
Bellow
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Disconnected the radio and just about everything else that is 'hot at all times' and the drain always shows up. Inevitably, I suspect, as long as its present at the battery terminals.
Interrogating the internet for an answer to the current on the battery posts but not found an answer yet.
OP
OP
Bellow
Hardcore MB Enthusiast
My MM doesn't object. It is however polarity sensitive as an ammeter. I though it would display with either probe orientation and merely reverse the polarity on the display.
Are you suggesting my reading of current across the terminals is bogus? I'm still at a loss as to why it doesn't register say, interior light being switched on or off - any ideas?
Stratman
MB Enthusiast
A fortnight is 336 hours. A quarter amp drain on a 100AH battery will drain it in 400 hours, less to make the battery effectively flat. The drain you measure will easily flatten it in less than two weeks.
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Connect the meter in series from the earth. Lock the car and push the door catches over. What measurement do you get after 15 mins?
OP
OP
Bellow
Hardcore MB Enthusiast
That was the battery from my smart after a fortnight. Normally it never sat unused for longer than one week.
edit PS. The current I quoted was across the battery terminals also - not the car itself.
That's how I did it and no bang! Or anything else untoward. My MM (Fluke 87) still works fine.
Last edited:
OP
OP
Bellow
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First job tomorrow - cheers.
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It should be no more than 0.06A
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Something is wrong then.
The Fluke will have a fuse in the ammeter line to prevent blowing the meter.
If you put the meter onto Amps and were to get another meter and measure between "COM" and "A" there would only be a couple of Ohms resistance, stick the leads across a battery and "pop".
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I use the cheapest Sealey MM to do this. Its unfused
Ted
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Bellow, see post 16 - I think you may have blown the internal fuse on the Fluke.
the meter will still work for testing volts/ohms but the 10 amp range will not.
once this is confirmed you will be able to test the current dray more accurately (it may still be 0.25 amps though!). My guess on the flashing testlight is that it is the clock - you can confirm this by disconnecting it.
Once the issue with the Fluke is addressed, as others have said - don’t put it across the battery or try to start the car with it in circuit as an ammeter as the resistance is so low. You will also overload it and blow the internal fuse if you attempt to pass over 10 amps through it.
the meter will still work for testing volts/ohms but the 10 amp range will not.
once this is confirmed you will be able to test the current dray more accurately (it may still be 0.25 amps though!). My guess on the flashing testlight is that it is the clock - you can confirm this by disconnecting it.
Once the issue with the Fluke is addressed, as others have said - don’t put it across the battery or try to start the car with it in circuit as an ammeter as the resistance is so low. You will also overload it and blow the internal fuse if you attempt to pass over 10 amps through it.
OP
OP
Bellow
Hardcore MB Enthusiast
I have not blown the internal fuse. I have blown both of them!
Why is it still functioning as an ammeter though - albeit polarity sensitive?
I'll search the 'net for fuses but if I can't find and/or want the meter fixed pronto - can I rewire the fuses (assuming I have fuse wire here)?
One fuse says 'see cap for symbols and Amperes' and on the cap is 'IR 100kA' and 'BUSS KTK-15'. On the other fuse, no reference to cap but on cap is 'BUSS BBS1'. What gauge/rating of fuse wire would I need?
Lighting (interior x 8 - and subsequently sidelights) was the highest current I subjected it to. And the battery short! (No more of that!).
I looked back over the period I have had this car and there was a 24 day period where the battery was disconnected and held charge, Connected, it drains to the point of no-start in a week. Still a car problem by the looks.
OP
OP
Bellow
Hardcore MB Enthusiast
So, problem solving is on hold (what's new? you ask) as the fuses ordered for the MM are going to be a while in arriving and after realising a Fluke 87 is 600 quids worth - better not bodge the fuses.
Not to overly delay things I've ordered a cheapo MM that will be here sooner. Meanwhile, I'll tackle the mechanical jobs. Maybe, just maybe, I can make some progress there....
(Been tempted to remove the damn thing's tyres. On the basis that, as the expression goes, 'anything with tits or tyres will cause grief').
Not to overly delay things I've ordered a cheapo MM that will be here sooner. Meanwhile, I'll tackle the mechanical jobs. Maybe, just maybe, I can make some progress there....
(Been tempted to remove the damn thing's tyres. On the basis that, as the expression goes, 'anything with tits or tyres will cause grief').
