Yup, < 10 V while cranking is a concern. I'd say the battery is at end-of-life.
Parasitic Draw
- Thread starter lapedrera
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I suspected the same thing. It is from May, 2020, with a 5 year replacement warranty.
I suspect the problem will now be convincing the manufacturer .. I suspect their warranty may not address that. (I am waiting for a call from them on Monday).
I dno't have any idea what would be technically considered a failure for low cranking V.
It does explain that the vehicle has been fine after it was boosted on the failure.
How accurate are the DC clamp meter's? Will they measure accurately down to say - 50mA?
My cheapy clamp meter measures AC current, but not DC.
I suspect it's not possible to make a clamp-type that measures DC, because the meter would measure the current inductively.
Edit: There are DC clamp-on ammeters. I don't know how they work. Live and learn...
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DC clamp meters exist. Link. Not as common but I think they are becoming more common.
Easier to make inductively coupled ones that work only at AC but the ability to sense magnetic fields at DC has been around a long time. Measuring it without error... a bit harder, all sorts of error sources.
You beat me to it. It must be tricky, because it seems to be offered only in upscale meters.
That I could buy, it's not "easy" to do. The field given off a wire is small and the method of sensing can have all sorts of noise and drift. Coupling all of the field and not changing due to how the clamp is held around the wire, probably a very high mu material--but if it has to have any sort of frequency response (400Hz?) it would have to be laminated. Or better, non-conductive, least it picked up a residual field (might cause it to read a current when none is present). But non-conductive, like ferrite materials, are often fragile. So I have no idea what secret sauce they used but it's cool all the same.
Just the first one I found. But I agree, I suspect many of the clamp on ones are going for high amps, not low amps. A traditional in-line meter is best here. Even if one has to resort to a traditional shunt like 100mΩ to drive a DMM in the 200mV range (1Ω would be easier to use but may be too much resistance for the high surge when all the systems come back to life).
Don't feel like looking for the "right" meter at this time. But the OP has the wrong one for sure.
If my memory is correct Uni-T make some budget DC clamp meters
I wonder if this is a "Cheap, or accurate - choose one" situation?
Edit: Available through AliExpress ... Hmmm ...
There are cheap clamp on DC meters even at Amazon. I have no idea how low they will read. I would suspect there for high voltage DC - still lots of DC motors used in Industrial believe it or not. This one is $23, but looks like only goes down to 1A.
https://www.amazon.com/KAIWEETS-Mul...51&sprefix=dc+clamp+meter,aps,127&sr=8-3&th=1
https://www.amazon.com/KAIWEETS-Mul...51&sprefix=dc+clamp+meter,aps,127&sr=8-3&th=1
Yup, I paid $30 for my Unit-T 210E a while back, although they've gone up in price a bit since then.
https://www.amazon.com/UNI-T-Multimeter-Voltmeter-Continuity-Capacitor/dp/B0BBMKLL5H
The Uni-T one I posted above has a resolution of 1mA (0.001A) for DC current, although accuracy isn't going to be crazy good at such low readings. Still, good enough to tell if you have 50mA of parasitic drain, and super convenient.
So it will measure one mA with the clamp? Or is that for the leads only?
Clamping is hard to get accurate with DC. It drifts pretty readily. It won’t be accurate enough for these low currents. Sometimes swapping the clamp back and forth can help get a feel for it.
A vilutmeter can be used to measure current if you place a shunt (low value resistor) inline with the load (the whole load goes through it) and then use the DVM to measure the voltage across the resistor. volts = current/resistor value. An old high beam would work for low current testing, below an amp. It would have too much resistance if there were any loads left on.
A vilutmeter can be used to measure current if you place a shunt (low value resistor) inline with the load (the whole load goes through it) and then use the DVM to measure the voltage across the resistor. volts = current/resistor value. An old high beam would work for low current testing, below an amp. It would have too much resistance if there were any loads left on.
gathermewool
Site Donor 2023
I have used a DMM (Fluke 117 in this case) and a pair of alligator leads to run in serious with the positive lead. The 117 has a max feature, so the max current drawn is displayed no matter how long you leave it connected.
So, connect a DMM that has this feature, in series with some alligator clamps, and walk away for a bit. Reset the max if the system draws a significant amount initially.
To be fair to the OP, I meant no offense earlier. I’ve never personally seen a DMM that couldn’t read current, and I’ve had quite a few over the past two decades. I’m just a shade tree mechanic though. I also know when I should ask for outside help so I don’t screw something up. Not knowing the difference between 11.X amps and volts would get me there quick and have me worried proceeding.
So, connect a DMM that has this feature, in series with some alligator clamps, and walk away for a bit. Reset the max if the system draws a significant amount initially.
To be fair to the OP, I meant no offense earlier. I’ve never personally seen a DMM that couldn’t read current, and I’ve had quite a few over the past two decades. I’m just a shade tree mechanic though. I also know when I should ask for outside help so I don’t screw something up. Not knowing the difference between 11.X amps and volts would get me there quick and have me worried proceeding.
With the clamp. This model actually cannot measure current with leads.
But again, there is going to be poor accuracy at such extremely low readings, so it may be 1mA or it may be 10mA in reality. But if you have parasitic drain, it's good enough to detect it.
You need to pause posting until you have accurate diagnostic information on the problem.
You can go to Harbor Freight and get a meter for an inexpensive price.
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