Dave Plowman (News) wrote:
In article ,
John Williamson wrote:
On 09/09/2020 15:05, williamwright wrote:

The problem with using an analogue meter is that if it's scaled for 25A
(which I need) small currents such as 2A hardly move the needle.

The only slight snag I have found using a clamp meter with a hall efect
sensor is that they are slightly affected by the position of the wire
inside the loop.

There will also be a constant small drain on the battery to run the
electronics.

As a bonus, the percentage reading is usually wildly inaccurate, so you
need to go by the voltage and accumualted amp hours readings..

What I've found too. Although don't have a brand new DC clamp meter.
They're fine for large currents, but near useless for measuring small
(less than say 10A) accurately. Which is mostly what I need.


I found one that's pretty weird. It almost looks like it's autoranging,
so you can get an extra digit after the decimal point. The pictures don't
tell you here, what's in the box.

https://imall.com/product/DC-Battery.../144-170622/en

The Amazon version shows a box which might be a "transmitter".
The second box with display is the "receiver". Range
suggests it might be Bluetooth (lowest class). It uses
a Hall Probe. It has a sign bit, that shows in some
pictures and not others in the imall picture set.

https://www.amazon.com/DYKB-Wireless.../dp/B07GD3BS4B

It's quite a tease, and you might end up buying it from Aliexpress.

Like most of these products, totally untraceable, can't get a manual.
And based on other product purchases of this type, the documentation
in the box is the "single sheet, good luck" kind.

I've been trying to find someone to vend just the Hall Probe part,
in the hope of finding a lower-amps one. These things *do* work
at lower currents, because the first one I ever worked on, at
work, was at lower currents. That was a long time ago for that
project. Even back then, you could see the stuff drift a bit
with time. I was making a PCB for student lab usage (a lab
about Hall Probes).

Paul