Did some Current Draw testing on my 99
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Joined: Jan 2016
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From: Sandown NH
Did some Current Draw testing on my 99
After about a minute
After about 15 seconds......
Voltage and current readings right after connecting meter in series. Note under hood light was on, everything else closed and off.
The set up I used
Since we are still buried in snow and freezing temps I was board and did some current draw testing on my 99. I've never had a dead battery and do not keep mine on a tender when not in use. Admittedly the longest it sits without being driven is maybe 2 weeks. Captions are in pic attached. Hope this helps others.
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
WELL,,,,,,,,,,,,,,,,,,,, 
,,,,,,,,,,,,,,,,, Unless you disconnect that hood light,,,,, you are NEVER going to see the real sleep current draw. 
If you let it set for 12+ min and the RAP times out, what does it read?????????????????
Bill
,,,,,,,,,,,,,,,,, Unless you disconnect that hood light,,,,, you are NEVER going to see the real sleep current draw. If you let it set for 12+ min and the RAP times out, what does it read?????????????????
Bill
Last edited by Bill Curlee; Mar 23, 2017 at 12:37 PM.
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From: Sandown NH
The last pic did not get up loaded so I posted it after the original post Bill. 30mA which had been ok as I have never had a dead battery.
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From: Sandown NH
Something else I want to add.....prior to this test the car sat for about a week. The battery was out of the car on a tender all winter--this is the ONLY time I use a tender. I put the battery back in a week prior to this testing--so the car had sat for a week before I took these readings. I did start the car before I did the testing. I checked the battery voltage on the DIC prior to starting and it read 11.8volts Despite this so called low battery reading the car fired up with out ANY hesitation. All last year I would occasionally check the battery reading on the DIC prior to cold starts and it was often 12.2 volts. NEVER had any stating issues or "gremlin" electrical issues either. I have read many times here if the battery reads less than 12.5 volts it is no good???
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From: Sandown NH
100%Purpose of the voltmeter on the dash is to provide the state of health of the cars CHARGING system and NOT the state of health of the battery.
With engine running you sort of read the output voltage of the alternator. Sort of because the voltmeter is AFTER the ignition switch and the contact surfaces in the C5 ignition switch are well known for pitting and carbon build up that presents a resistance over which a voltage drop occurs producing a meter reading less than the actual output voltage of the alternator...
With the key ON and engine OFF you are reading the loaded battery voltage. Loaded because there are many electrical circuits that are powered with the key in the ON position but the engine OFF presenting an electrical load to the battery. The significance of such a reading is basically meaningless.
Now having done this test I understand that. I was pretty surprised how my current just the under hood light was drawing! My underlying point of this post was more to point out if someone's battery is going dead in less than 2 weeks they have an electrical draw somewhere. Statements like "they all do that" and "you NEED to have it on a tender when not in use" are just plain silly!
I guess a battery tender is easier as a fix than actually trying to find what the real problem is. 
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Joined: Mar 2017
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From: Orlando Florida
"a battery tender is easier as a fix than actually trying to find what the real problem is"
Well that is what I'm thinking. So many, many little things that aren't quite right, and it could quickly turn into a bottomless rabbit hole trying to find any one particular current draw...
Well that is what I'm thinking. So many, many little things that aren't quite right, and it could quickly turn into a bottomless rabbit hole trying to find any one particular current draw...
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From: San Jose, CA
30mA is a pretty good (small) draw when the car is off.
If you have a battery rated for 100 minutes at 25 amps, which is fairly normal, that's 2500 amp-minutes - at 30mA, that's 2500 / 0.030 = 83333 minutes = almost 58 days.
I make sure to run mine at least once every two weeks, which is easy since even the non-stop california winter rain this year did let up once a week.
If you have a battery rated for 100 minutes at 25 amps, which is fairly normal, that's 2500 amp-minutes - at 30mA, that's 2500 / 0.030 = 83333 minutes = almost 58 days.
I make sure to run mine at least once every two weeks, which is easy since even the non-stop california winter rain this year did let up once a week.