Hello,
I have to use AUX 1 input to disable FeedIn. But I need a very long cable (40m) to the smart meter, which will control this input.
I wonder, that I’m not able to finde a documentation about the electrical characteristics of the AUX interface.
What kind of input is it?
Which voltages are present there?
Which current will flow?
Is it galvanically isolated from the rest of the multiplus and from the other aux input?
Michael
Hi,
The Aux input terminals consist of a ground connection (inverter local) and a sense connection which has a resistive pull up to 12V. Only minimal current will flow in the control loop.
No it is not galvanicaly isolated: you must ensure that this does not short to any other voltage as it can destroy the control board in the inverter (in extreme case). These contacts can be used for long distance signaling, but must be isolated from any other voltage or interference.
Hi Mike,
thank you for this information. But is there no official documentation about that?
Here a pullup to 5V is shown:
But what is the source for that information?
If possible, I would definitely use a small relay or optocoupler as detailed in the link.
That way, you benefit of electrical isolation, voltage level translation, interference reduction/elimination. It all depends on smart-meter capability to drive a relay or LED.
A single channel optocoupler like xx817 is very reliable and really cheap.
That’s a post, not Victron information.
The Pull up is quite high resistance, and if a low impedance volt meter is used to measure this it will give a false reading.
It is possible to use a second relay to give additional isolation: One relay close to the multiplus, and the second relay or switch close to the control point - in your case 40m away.
I also had this idea with the additional relay. But in this case, I need an additional power supply as well. As I understand, the smart-meter only has a potential free contact that cannot drive a relay.
As I understand, you also have no idea if there is some official specification about the aux inputs?
The posting in my link includes a screenshot of a site or pdf that looks like an official document.
If you use this additional relay, take it’s power from the main battery, via a small fuse. No problem.
Then the relay coil is driven by the potential free (dry) contact of the smart meter, however you do need to include a back emf diode across the relay coil to prevent the relay in the smart meter freezing.(getting welded closed).