How to read amps on a Multimeter?
10-03-2012, 10:50 AM
#1
Heel & Toe
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How to read amps on a Multimeter?
Okay - I've followed Bill Curlee's advice/threads on Battery Drain Tests.
He mentions 20 milliamps is good - once the car has gone to sleep.
I'm showing the following:
When meter is set to A - .104
When meter is set to mA - 1.04
Does this equate to 104 milliamps? or am I at 10 milliamps?
I checked every fuse under the hood and the footwell - not one fuse changed the reading.
Thanks
He mentions 20 milliamps is good - once the car has gone to sleep.
I'm showing the following:
When meter is set to A - .104
When meter is set to mA - 1.04
Does this equate to 104 milliamps? or am I at 10 milliamps?
I checked every fuse under the hood and the footwell - not one fuse changed the reading.
Thanks
10-03-2012, 11:03 AM
#2
Team Owner
.104 A = 104 mA
On mA scale, are you sure it read 1.04?
for the purpose of what you are doing, setting to the A scale is just fine. You've got 3 digits of resolution, and probably a 5% accuracy. Close enough for this. If you want to get fussy later, then switch to mA and get a more accurate reading. For now, you just know the draw is too much.
Leave it sit for a minute that way, and see if the reading doesn't go down some. Mine starts at 300ma, then to 150, to 80, and some time after drops to 25.
On mA scale, are you sure it read 1.04?
for the purpose of what you are doing, setting to the A scale is just fine. You've got 3 digits of resolution, and probably a 5% accuracy. Close enough for this. If you want to get fussy later, then switch to mA and get a more accurate reading. For now, you just know the draw is too much.
Leave it sit for a minute that way, and see if the reading doesn't go down some. Mine starts at 300ma, then to 150, to 80, and some time after drops to 25.
Last edited by K-Spaz; 10-03-2012 at 11:06 AM.
10-03-2012, 11:12 AM
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10-03-2012, 12:31 PM
#4
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Are the fuses in the meter good. Some meters have no fuse for the A scale and a small fuse for the mA scale. I would be suspect of the meter unless you can get both ranges to read similar values.
10-03-2012, 03:14 PM
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CI 6,7,8,9,11 Vet
St. Jude Donor '08
Are you POSITIVE that you have the meter set up properly and,, are you in { SERIES } with the circuit???????????????
If it were 1.04 AMPS,, you could NOT see .104 ma
Look at it this way .999 milliamps is ONE micro amp less than 1 amp.
SO,,, your .104 ma can NOT be 1.04 amps. That reading does NOT make any sense..
I suspect the meter OR the method in which you using the meter OR an improper meter set up.
The NEGATIVE cable on the battery MUST be disconnected from the battery and the meter leads MUST be placed between the battery terminals and the battery neg cable.
The meter mode selector MUST be in the AMP or Milliamp position. Most meters have a specific separate jack to read current.
Recheck your set up. 20 milliamps should read out as .020 on the AMP SCALE OR 20.0 on the milliamp scale.
If it were 1.04 AMPS,, you could NOT see .104 ma
Look at it this way .999 milliamps is ONE micro amp less than 1 amp.
SO,,, your .104 ma can NOT be 1.04 amps. That reading does NOT make any sense..
I suspect the meter OR the method in which you using the meter OR an improper meter set up.
The NEGATIVE cable on the battery MUST be disconnected from the battery and the meter leads MUST be placed between the battery terminals and the battery neg cable.
The meter mode selector MUST be in the AMP or Milliamp position. Most meters have a specific separate jack to read current.
Recheck your set up. 20 milliamps should read out as .020 on the AMP SCALE OR 20.0 on the milliamp scale.
Last edited by Bill Curlee; 10-03-2012 at 03:17 PM.
10-03-2012, 03:57 PM
#6
Drifting
99% sure it was on "200 ma" setting with the 1.04 reading. This is why I always buy digital autoranging multimeters! I'm an electrical engineer, and I still trick myself out on what the reading actually says sometimes.
Like the other's said, just leave it on "Amps", and let the car sit for a bit and get another reading.
Also make sure you leave the hood open and unplug the underhood light
Like the other's said, just leave it on "Amps", and let the car sit for a bit and get another reading.
Also make sure you leave the hood open and unplug the underhood light
10-03-2012, 05:53 PM
#7
Team Owner
Are you POSITIVE that you have the meter set up properly and,, are you in { SERIES } with the circuit???????????????
If it were 1.04 AMPS,, you could NOT see .104 ma
Look at it this way .999 milliamps is ONE micro amp less than 1 amp.
SO,,, your .104 ma can NOT be 1.04 amps. That reading does NOT make any sense..
I suspect the meter OR the method in which you using the meter OR an improper meter set up.
The NEGATIVE cable on the battery MUST be disconnected from the battery and the meter leads MUST be placed between the battery terminals and the battery neg cable.
The meter mode selector MUST be in the AMP or Milliamp position. Most meters have a specific separate jack to read current.
Recheck your set up. 20 milliamps should read out as .020 on the AMP SCALE OR 20.0 on the milliamp scale.
If it were 1.04 AMPS,, you could NOT see .104 ma
Look at it this way .999 milliamps is ONE micro amp less than 1 amp.
SO,,, your .104 ma can NOT be 1.04 amps. That reading does NOT make any sense..
I suspect the meter OR the method in which you using the meter OR an improper meter set up.
The NEGATIVE cable on the battery MUST be disconnected from the battery and the meter leads MUST be placed between the battery terminals and the battery neg cable.
The meter mode selector MUST be in the AMP or Milliamp position. Most meters have a specific separate jack to read current.
Recheck your set up. 20 milliamps should read out as .020 on the AMP SCALE OR 20.0 on the milliamp scale.
Last edited by 65GGvert; 10-03-2012 at 05:55 PM.
10-03-2012, 06:14 PM
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CI 6,7,8,9,11 Vet
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EXACTLY! 
The 1.04 reading is out to lunch.. 
The 1.04 reading is out to lunch..
10-04-2012, 08:53 AM
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Thanks guys - I'm pretty sure I have the connections correct.
I'm going to redo the test tonight and if I can't figure it out I'll post pics of the meter/readings.
I'm going to redo the test tonight and if I can't figure it out I'll post pics of the meter/readings.