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diy solar

Silly accurate current sensors

M

MattiFin

Solar Enthusiast
Joined
Dec 31, 2020
Messages
692
This goes to more advanced hacks but if you need really accurate high current measurements you can find used fluxgate (no kidding!) sensors from ebay cheaply.
600A ”ultrastab” are linear to 1ppm and despite the 600A max current you can measure rather small currents with these.

Before You all get exited notice that these still need secondary shunt (or dvm with accurate current range) and +-15v regulated linear power supply.
 
This sounds interesting.

Do you have a link to the eBay offer?
Found them.
Search for "Ultrastab"

Next step is to figure out how it is to be used...
On my main AMmeter...
That expects input from a 100mv shunt.

Shunt is available,
linear power, not a problem.
How to use...
That's worth a study :)
 
Last edited:
I found explanation document

Not sure if it can be modified to be used in simple installations.

It looks like one needs the matching high sensitive (and expensive) equipment to be able to use.

The $150,- is a lot of money, but if it can solve my "problem" of more accurate measure low usage,
That could be acceptable.
If it's just the start of a long list of additional costs...
Then it's not :)

My low usage goes as low as 5A
Where my high usage can peak around 300A
I am having longer periods of usage between 5 and 50A.
And longer periods around 300A.

I haven't installed my 400A shunt yet, so I don't know what it's results will be.
I am afraid it will be too inaccurate on the longer periods lower usage.
 

Attachments

  • High_Current_Measurement_Guide (1).pdf
    2.2 MB · Views: 6
You can measure 400A 60mV shunt resistor with maybe something like 0.07A resolution or offset error. Need charge counter with better than 10uV resolution. Below that it is guesswork because of the thermovoltages generated by the shunt and wiring.
 
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