Combiner Box voltage and current monitoring

[kosmonooit]

Greetings,

I am rolling my own version of this device:

Billion SG3204S -   Solar DC 4 Strings Meter
http://www.billion.com/Energy Management/Solar Monitor Meter Series/Billion SG3204S


I am trying to figure out why they monitor the current on the negative side of the circuit - number wise surely it doesn't make much diffs which side but is there some other reason?



I first came across this at a Solar Show in the Philippines - and the sales guy made a point of mentioning this, but I didn't press him as to why.

Any ideas?

Once I am done I will open source my design and s/w - I have done galvanic isolation, RS-485 interface, environmental monitoring etc

Thanks.

[Seekonk]

I assume they are using a shunt and it is just cheaper to implement on the low side like all those cheap Power monitors from China that are sometimes hard to implement.

[Inverted18650]

@kosmonooit,

Do you have a link to your build? I'll follow this thread & hope you will update us. Thanks

[David Hess]

I am trying to figure out why they monitor the current on the negative side of the circuit - number wise surely it doesn't make much diffs which side but is there some other reason?

The reason is either convenience or habit.

In practice, I find that high and low side current sensing are equivalent in difficulty once you learn the more obscure (old) circuits for doing them so the convenience factor becomes where to insert the current shunt.