EM and OutbackPower

Hello and a happy new year 2017 to all!

High up (5700ft) in the southern french Alps my small off-grid Photovoltaic (PV) system (1kWp, 30kWh lead-acid Bats plus a 2kVA generator) is DC managed by an Outback Power outfit including a Mate3 for communication.

Snow is good for skiing but not for old bones living up there in winter. So we flee in Lyon 6 months a year and need monitoring. It is organized with a Raspberry pi to read Mate3 and send the data via a router-modem-3G to lsdx.eu/GPV_ZSDX. This setup in only lit up 5 minutes every hour to save power and for Internet security. It did work well for a time but now the cat5 socket in Mate3 does not connect when my router is lit up. A known and unsolved issue at Outback Power;

As I am NOT connected to any grid, water and 3G excepted, I hope to find an alternative solution for monitoring. But apparently your little blue captors only work on AC!
The data manger uses 2 shunts (in and out) which give a small voltage.

  • Would there be a way to send this voltage to one of your modules without disturbing Outback Power?
  • Is there a way to measure DC voltage?.

More info if needed

Lionel

Yes, that is correct. They are current transformers, and transformers only work on a.c. Unfortunately, that also means our emonTx, emonPi and emonTx Shield are designed to accept only those as the current-measuring device, so these will not work for you without modification.

Yes, to both questions. But not to one of our modules. I think you need an analogue input board and your/another Raspberry Pi, connected by Ethernet or WiFi to your router.

You can measure d.c. voltage - that is what the analogue input does. The big problem you face is isolation. One side of every voltage you measure must all be connected together and to ground. If one side is not at ground potential (0 Volts), then you will need to include some means to isolate the circuit you are measuring from the device that is doing the measurement. Without knowing exactly what you have, it is difficult for me to say what you need to do.
(And I include your two shunts in that isolation problem - one side of each must share a common connection and therefore be at the same voltage.)

I think something like this has been done before, if you search this forum and the old forums, you will probably find some useful information.

Thanks Robert.

Thanks Robert,
That post was just to establish contact.
Will report if/when I find some solution
Lionel

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