question

Tien avatar image
Tien asked

SmartShunt Inaccurate Current

Hello,

I seem to be getting inaccurate current with my SmartShunt 500A.
I have done the calibration, with nothing connected to the load side and has not made any improvements.
Not sure if it has only recently happened or has always happened.

I have tested it with a Victron IP22 30A Charger and is the only thing connected to the Load Side.

The below are the results.

Charger SmartShunt Lithium Battery Difference Between Charger & SmartShunt Difference in %
7.5A 7.22A 7.4A .28A 2.65%
15A 14.53A 14.9A .47A 3.13%
25.6A 24.92A 25.6A .68A 3.73%


Also did a small current draw

SmartShunt Lithium Battery Difference Between Charger & SmartShunt Difference in %
-2.48A -2.6A 0.12A 4.61%
-5.61A -5.9A 0.29A 4.91%


What do you guys reckon is happening here? Is it within spec or how do I make it more accurate?


SmartShuntbluesmart ip22
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1 Answer
Alexandra avatar image
Alexandra answered ·

@TieNN89

It is not unusual for different measuring devices to have up to a 3% difference in readings. See this article.

I have several digital meters Fluke, UniT and some cheaper ones. What you are seeing is not unexpected although a little unnerving when you first discover it.

You will also see most battery manufacturers allow 0.3 to 0.5 voltage range for battery charging, this is sort of to accomodate the differences of different devices. And also voltage and resistance differences for cable drop etc.

But really you can check torque on all your terminals and crimps as well (corrosion maybe as well?) as it is also possible something has changed there with thermal cycling and conditions in charging.

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