Is it my battery or something else? (2016.5 CX-5)

Conrad 16.5 said:
I saw those two wires inside the clamp too. I'm not sure how that will affect the reading as they both appear to be ground wires coming from the battery. Those wires look somewhat different than the wires on my CX but on my car one wire connects to a ground point near the shock tower and the other runs underneath somewhere, they both Y off of the negative battery terminal.
Click to expand...
Yes, I believe the 2 (and sometimes 3) wire configuration is typical for many vehicles these days.

I just accept what's written about 2 wires clamped giving invalid readings, because there's no way to confirm it by trying to test the constantly changing current on a vehicle. It would take some kind of static test setup, and I just can't get energized enough to do something like that :rolleyes:
 
edmaz said:
It appears that you have more than one wire inside of the clamp. If so, all of the doc I've read says the reading is not valid if more than one wire is clamped. I've used my clamp meter on those negative wires for 'shutdown' type of testing (where the current values are very low and have a slow rate of change), by testing both wires separately and adding the current values. I don't know if it's even possible to be quick enough to be able test both wires separately with a clamp meter, on a running vehicle, where the draw is high and changing rapidly.
Click to expand...
For DC current, I can't imagine why that would matter. I could see a problem with two AC wires, where the phase wasn't the same.
 
skid00skid0 said:
I measured the wires separately. The 'main' wire measured 205.4 amps peak. The chassis/inner fender measured 63.9. That was a surprise. I expected them to be near identical.

A google search took me here: Can I measure multiple wires (same current direction) with a clamp meter?

Consensus was that DC current can be measured thru multiple wires at one time. I wonder if they measure closer if the wires are touching, vs on either side of the clamp meter...
Click to expand...

That's strange. I too would have expected the readings to be very close to the same.
 
Conrad 16.5 said:
That's strange. I too would have expected the readings to be very close to the same.
Click to expand...
If that other wire through the clamp meter is a "body ground" wouldn't it just be the lower current leg of a parallel circuit. The higher current leg being the current path from positive terminal through starter and engine block and back to negative terminal. Maybe some effects of devices active within vehicle(fan, heated seats etc) also. If this is the case I could see different current readings.
 
ColtX-5 said:
An amp meter doesn't require zeroing! LOL!
Click to expand...

Laugh it up all you want but a clamp ammeter most certainly does require zeroing!

How many have you used?

www.fluke.com

How to Measure Current with a Clamp Meter

Measuring ac current with a clamp meter’s jaws. Note: Current flowing in opposite directions cancels each other. If current is moving in opposite directions, place just one conductor within the clamp during measurement.
www.fluke.com www.fluke.com

How to measure current with a clamp meter​

Clamp meters
Steps for measuring ac or dc current using a clamp meter's jaws:
Pre-measurement steps (to avoid electrical shock or personal injury):
  • Disconnect test probes from the meter.
  • Keep fingers behind tactile barrier on face of meter.
  1. Turn the dial to the proper function, either A ac or A dc. You should see the jaws icon (
    Jaws icon
    ) in the display, indicating that the measurement is coming from the jaw.
  2. Note: When the measured current is < 0.5 A, the center dot in the display icon (
    Jaws icon
    ) will flash on and off. When current is > 0.5 A, the center dot will be steady.
  3. Before taking dc current measurements (if your meter is equipped to do so): Wait for the display to stabilize, then push the Zero button to ensure correct readings. Zeroing the meter removes dc offset from the reading. The Zero function works only when the dial is set in in the dc current measurement position.
  4. Note: Before zeroing the meter, make sure the jaws are closed and no conductor is inside the jaw.
  5. Press the jaw release level, open the jaws and insert the conductor to be measured inside the jaw.
  6. Close the jaw; center the conductor using alignment marks on the jaw.
  7. View the reading in the display.

Still laughing?
 
Last edited:
Conrad 16.5 said:
Laugh it up all you want but a clamp ammeter most certainly does require zeroing!

How many have you used?

www.fluke.com

How to Measure Current with a Clamp Meter

Measuring ac current with a clamp meter’s jaws. Note: Current flowing in opposite directions cancels each other. If current is moving in opposite directions, place just one conductor within the clamp during measurement.
www.fluke.com www.fluke.com

How to measure current with a clamp meter​

Clamp meters
Steps for measuring ac or dc current using a clamp meter's jaws:
Pre-measurement steps (to avoid electrical shock or personal injury):
  • Disconnect test probes from the meter.
  • Keep fingers behind tactile barrier on face of meter.
  1. Turn the dial to the proper function, either A ac or A dc. You should see the jaws icon (
    Jaws icon
    ) in the display, indicating that the measurement is coming from the jaw.
  2. Note: When the measured current is < 0.5 A, the center dot in the display icon (
    Jaws icon
    ) will flash on and off. When current is > 0.5 A, the center dot will be steady.
  3. Before taking dc current measurements (if your meter is equipped to do so): Wait for the display to stabilize, then push the Zero button to ensure correct readings. Zeroing the meter removes dc offset from the reading. The Zero function works only when the dial is set in in the dc current measurement position.
  4. Note: Before zeroing the meter, make sure the jaws are closed and no conductor is inside the jaw.
  5. Press the jaw release level, open the jaws and insert the conductor to be measured inside the jaw.
  6. Close the jaw; center the conductor using alignment marks on the jaw.
  7. View the reading in the display.

Still laughing?
Click to expand...

Yes, still laughing! I have 2. One on my solar battery bank and a Klein for general use that also measures AC current. If nothing else, turning on the meter "zeros" it. 🤣 Perhaps you need to modernize.

Measuring the current of 2 or more wires with an inductive ammeter measures the net current flow. I.E. the current flow adds. Were one wire to be charging and the other discharging, you would see the sum of the 2 currents with the discharge seen as negative. The same applies when current is flowing out of the battery, as seen above, the current in each wire adds.
 
Clamp meters in DC mode sense magnetic fields. You know-like Earth's, and engine and body components.

My meter was showing up to 0.2 amps, with the negative wire clamped, with the car OFF for a week. If I moved the meter, that amount changed, depending on how I moved the meter.

I hope you don't work professionally with electronics.
 
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