GP964

Hi All,

I've read previous post on battery drain either from the hood light, CCU, blower fan, etc. I would like to find out how i can trace my drain. I have a fluke multimeter model 77 which should do the job.

I've heard of disconnecting the negative cable from the negative terminal, then place the multimeter positive (red) cord againts the negative terminal and the negative (black) cord againts the negative cable, does this sound right????

I'm ready to start pulling fuses, once i have the procedure correct.

Thanks

GP 964

DarrylH

Yup, that's it. Good hunting. Common ones: door and compartment lid switches, light switches, CCU fault of some kind. Should be possible to get to about 25 ma max. (unless you have an aftermarket something-or-other that has a high resting current draw.)

GP964

Hi All, Tried this procedure and my multimeter is giving me a reading of 5.20 amps, I don't know if im doing this right. Here's how i hooked it up... (disconnect the negative cable from the negative terminal post, place the positive (red) lead of my multimeter on the negative terminal post and placed the negative (black) lead to the disconnected negative cable.) In doing so i'm getting a 5.20 reading. I've pulled all the fuses/relays in the trunk and engine bay the # 5.20 did not move.

Any help would be great

Thanks
GP

bhensarl

Could that be 5.20 milliamps? The 77 (I have one too) is auto ranging, so could it be 5.20 milliamps in which case you'd have a very low drain?
Brian

DarrylH

I seem to remember something about a wire from the radio portion of the alarm giving a current draw of about 500 ma...and I see you have a pretty elaborate stereo system. Any chance it's the infamous 'green wire syndrome" of which I've heard? I don't have Adrian's book at home here, but I think it's detailed in there. Might be worth a look.

5 amps seems high, so I always start thinking it's an order of magnitude thing...

914und993

5.20 amps is really high. Your battery should be good and dead in 8 hours or less at that rate. If its really that high, you have a problem. But you are hooking the ammeter up correctly.

Chip

GP964

Update: Hey all, the numbers of 5.20 that I got earlier was wrong, On my multimeter (Fluke 77 III), I had the red lead wire coming from the Volts instead of the 300ma or 10A.

So this time I took off the positive + cable from the battery, then took the positive + red lead from the fluke meter connected it to the disconnected positive + cable. Then connected the negative - lead from the multimeter to the positive + battery terminal.

Here are the #'s im getting;

at a 10A setting it shows -0.009 DC
at a 300ma setting it shows OL (overload)

Does these numbers sound right? Could this drain my battery after 2-3 days of no use?

Thanks GP

darth

GP

The lead connections are interchangeable - one way you'll get a postive reading and then swapping them you should get an identical negative reading. The .009 (i.e 9 ma) reading while on the 10 A scale is well within the 300ma range and because you're getting an OL (i.e. overload) reading I suspect you've blown the multimeter's inline fuse. Replace the fuse with the proper rating fuse and when you reconnect to take readings make sure you don't have any major current drains such as compartment lights etc. which can take a few amps otherwise you will reblow that same fuse. When I checked my current draws I discovered the aftermarket radio was the greatest draw at about 60ma (i.e 0.06A).

Hope this helps
Bill
90C2

Lorenfb

Both readings should agree, which they don't. You may have a damaged meter.
You need to "calibrate" the meter with a known current, e.g. a light bulb, or a test
light. Without having done this, the actual true current draw will be unknown.

Julian Thompson

Bijesus you're struggling here. I am an auto electrician so perhaps I can help.

1) Forget the car for a second. Learn to drive the meter. What we want is the two meter cables plugged in to the 2 correct holes to read AMPS. It sometimes says "10A DC" etc on the meter - you need to read the meter manual or post a pic of the meter but this must be correct.

2) Second, the meter must be set to read AMPS as the thing just won't work right otherwise - you should see the suffix "A" at the end of the readout if you have this right.

3) Now remove the negative terminal of the car from the battery and insert the meter in series with the car and the battery. This will read the current draw. Note that if you turn on the full beam or try to start the car or something daft with the meter in the middle you will exceed the max current handling of the meter and you will blow the meter's internal 10A fuse which in the case of a Fluke meter will necessitate the strip down of the meter to change this.

4) If the meter reads 5.2A then you have a MASSIVE drain. You can work out how long the car should last because, for example, a 52Ah battery should last 1 hour @ 52A drain or, of course, 52 hours @ 1A drain.

5) An ordinary car should drain no more than about 0.1A at the most unless there is a good reason why it is drawing more.

Good luck

Julian

JasonAndreas

You might also want to get your hands on TSB-9402 Part Identifier 2706 "Diagnosing Discharged Battery". Its 8 pages long and goes through bad relays, alternator, etc and it lists the current draw for various components in the 964. Adrian's book is also very handy when you've never done this before.

GP964

Hi All,

Finally got Adrian's book yesterday, wow I spent hours reading it.

Any how I did his test on the battery, drove it about 15 min, then took the fluke and tested volts right after, registered 12.63 Volts with the car off, 14.3 Volts with the car at idle, and when I started the car the Volts only dropped to 10.9, so it is well within Adrian's range.

Another thing I check for was Adrian's AC diode test while the car was idling, according to Adrian's book there should be zero "0" on this test, mine registered at .150, What does this mean?

I did the amp test again according to Adrian's directions here are the figures:

10A setting = between 0.07-0.08
300ma setting = 81.3

Do are these figures show I have a drain? The car has a aftermarket alarm and sound system.

Thanks again
GP

p.s. Adrian awesome book

DarrylH

80 mA sounds about right. What started you down this path in the first place? Is your battery going flat quickly? With that level of current draw a normal battery shouldn't go flat for about 6 weeks. (Time to a no-start would be much shorter, of course.)

Sorry I don't know about the acceptable level of AC in a DC system. I'm sure someone else will, though.

GP964

Hi Darryl,

Reason I posted this information is because my battery would be dead in 2 days
For example: I would drive the car all day on friday, not use it on sat and sun, by monday the car would not start.
The alarm is not on, just stays in the garage.

GP

Lorenfb

"Another thing I check for was Adrian's AC diode test while the car was idling, according to Adrian's book there should be zero "0" on this test, mine registered at .150, What does this mean?"

Don't be concerned about this "ripple voltage". The key is the voltage you got ~ 14.0.
The ripple voltage is an indication of bad alt. diodes and will be > 1.0 volts A.C.
Also, the alt. light will usually glow with bad diodes.

The current draw you got (80ma) is a little high, but the battery
should last a couple of weeks without driving/running/charging.