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Interesting. Didn't know they even had clamps that could measure DC current. I just ordered a Klein CL390, which has the meter integrated into the clamp. Thanks.
Interesting. Didn't know they even had clamps that could measure DC current. I just ordered a Klein CL390, which has the meter integrated into the clamp. Thanks.
cancel it
I showed a small clamp for low measuring and smaller wires
yours won't measure what you need accuratly
cancel it
I showed a small clamp for low measuring and smaller wires
yours won't measure what you need accuratly
The meter has a 4000 count resolution so the 40A range should have a resolution of 10mA. I'll bench test when it arrives to confirm. The clamp is larger, but I don't foresee an issue getting it into any of the SL's fuse boxes.
I read a lot of reviews for a number of different low-cost DC AMP clamp-ons. It looks like accuracy in the lowest range is an issue for all of them due to stray magnetic fields.
The meter has a 4000 count resolution so the 40A range should have a resolution of 10mA. I'll bench test when it arrives to confirm. The clamp is larger, but I don't foresee an issue getting it into any of the SL's fuse boxes.
I read a lot of reviews for a number of different low-cost DC AMP clamp-ons. It looks like accuracy in the lowest range is an issue for all of them due to stray magnetic fields.
ok then
just saying this because I had one of those large
good luck !
Received the CL390 and bench tested it. The meter supports counts down to 10 mA on its 40A range, but it was very noisy in that low range. The reading was constantly fluctuating +/-20mA and sometimes more when you moved the meter around. I didn't actually purchase the meter to measure battery drain and I don't think it would be a good choice for that application. Can't speak for the PeakTec clamp, maybe it's less noisy in that range?
A cheaper approach that I've used before for auto battery drain testing is just to use the series Amp function on a regular digital meter. With either method you have to pull the fuse. The difference is that with a series test you need to put the meter leads in series with the circuit so it would need a different adapter. The meter introduces a small resistance into the circuit (about 1 ohm for my meter) but even at higher current draws (when the circuit is not shut down) that results in only a very small error in the reading. For the series test the lower the current draw the smaller the error, which is the opposite of what you'll see for clamp meters.
A lot of meters have two ranges for Amp testing. I suggest using the higher range. On my meter that resolved down to 10mA, which is more than adequate for the test. I suggest doing that because the Amp test jacks on meters are fused. If the current even momentarily exceeds the low range of the meter it'll blow the fuse in the meter.
Having said all that I'd like to point out that it's very tricky to get reliable quiescent current draw for a car. As a minimum you have to have all doors and the trunk closed and keep the key fob out of range of the car. The car should then eventually shut things down to a minimum to conserve battery. But, it may periodically wake up some circuits for a brief period of time and then shut them down again. It's not easy to predict what a car full of computers might do when you're not around. A data logger would be the only way to accurately determine the amount of total power draw over time.
Received the CL390 and bench tested it. The meter supports counts down to 10 mA on its 40A range, but it was very noisy in that low range. The reading was constantly fluctuating +/-20mA and sometimes more when you moved the meter around. I didn't actually purchase the meter to measure battery drain and I don't think it would be a good choice for that application. Can't speak for the PeakTec clamp, maybe it's less noisy in that range?
A cheaper approach that I've used before for auto battery drain testing is just to use the series Amp function on a regular digital meter. With either method you have to pull the fuse. The difference is that with a series test you need to put the meter leads in series with the circuit so it would need a different adapter. The meter introduces a small resistance into the circuit (about 1 ohm for my meter) but even at higher current draws (when the circuit is not shut down) that results in only a very small error in the reading. For the series test the lower the current draw the smaller the error, which is the opposite of what you'll see for clamp meters.
A lot of meters have two ranges for Amp testing. I suggest using the higher range. On my meter that resolved down to 10mA, which is more than adequate for the test. I suggest doing that because the Amp test jacks on meters are fused. If the current even momentarily exceeds the low range of the meter it'll blow the fuse in the meter.
Having said all that I'd like to point out that it's very tricky to get reliable quiescent current draw for a car. As a minimum you have to have all doors and the trunk closed and keep the key fob out of range of the car. The car should then eventually shut things down to a minimum to conserve battery. But, it may periodically wake up some circuits for a brief period of time and then shut them down again. It's not easy to predict what a car full of computers might do when you're not around. A data logger would be the only way to accurately determine the amount of total power draw over time.
I predicted that your clamp was junk
I can tell you that PeakTec is the cheapest solution and that my solution is the one to follow
many workshops use this as the cheapest real solution
hope next readers just do what post as my post was not a guess
I predicted that your clamp was junk
I can tell you that PeakTec is the cheapest solution and that my solution is the one to follow
many workshops use this as the cheapest real solution
hope next readers just do what post as my post was not a guess
Definitely not fair to call the Kein clamp junk. The smaller jaws on the PeakTech probably make it less susceptible to noise, but both devices fall into the category of "low cost" and probably have similar accuracy.
It seems to me the simplest way to test draw on a battery is to put the clamp on the battery cable. No fuses to pull. The larger jaws are better for that because the cables to the battery are large. Here's the CL390 clamped to the starter battery on my car. I left it on there for maybe 10 minutes. The lowest draw recorded was about 220mA. I think it would drop more if I left it overnight. I'll try that sometime.
nothing personal, I was just very upset by the quality and accuracy when I bought the same kind of clamp as you did.
the other issue is the clamp size
draw should be less than 65
another problem is that some modules can shut off, then later back on ect
drain can be a nightmare, and so if you are not luck to find the problem that way, you will need to do the workshop fuse method
forgot
larger clamp is not better as you can not measure smaller wires and its not precise at all even for battery cables
far too big
with the workshop used clamp, if for some reason you want to do the battery anyway, you can hook up a slightly thinner cable temporarily
01-07-2021, 05:22 AM
Find your battery drain
