Inverter Dry Contact - Use

[Dairyfarmer]

Anyone using the dry contactors on their Axpert inverter? The inverter is situated on my back veranda for safety and noise reasons. In my lounge I want to put 2 pilot lights. Setting Program 38 to "enable", then connecting NC to a green light and NO to a red light. When inverter is using battery / solar the green goes off and the red illuminates. when utility is restored then green illuminates and red goes off.

The next stage will be to incorporate some part of automation so that I can, for example, have the Sonoff switch on my fridge turn off 10 minutes after utility fails and turn back on when utility returns. That way i can include more, what I call, medium draw appliances (300-500w). to my inverter without the fear of them using too much battery over extended utility failures. Also would be nice to have the utility connected devices only turn back on 5 minutes after utility is restored. I do have some 3500W/16A Sonoff switches on their way from China. So the laundry, dishwasher, geyser, ovens and kettle only become available 5 minutes after utility is restored.

Any thoughts?

 

[riscbroker]

I know you can use a Sonoff Basic to delay power being switched through to whatever device/s when utility is restored. Just set it up in the loop timer on the respective switch. I did this a few days ago to protect my fridge etc from voltage fluctuations when power comes back on after loadshedding.

 

[russellw1]

The Axpert needs some sort of load shedding otherwise the batteries can't last 2 hours (unless there is good solar power). We have 3 phase power so I have connected only lights and the tv plug socket to the red phase and then I disconnect power to the Axpert and connect it to the generator/mains changeover switch. That shows about 500 watts with the computer and wifi working as well. Eskom put a data logger on the power and said the phases are unbalanced but everything works so I'm not going to change the wiring. The Axpert is in a cottage which is off grid on sunny days (solar geyser and electricity). I am still working on Sonoff POW switches and Openhab smart home software to see if some other loads can be added without overloading or draining the battery.

What I have discovered is I had to Install a separate 12 volt lighting system as backup for when the Axpert shuts down on low battery.

 

[Steamy Tom]

The Axpert needs some sort of load shedding otherwise the batteries can't last 2 hours (unless there is good solar power). We have 3 phase power so I have connected only lights and the tv plug socket to the red phase and then I disconnect power to the Axpert and connect it to the generator/mains changeover switch. That shows about 500 watts with the computer and wifi working as well. Eskom put a data logger on the power and said the phases are unbalanced but everything works so I'm not going to change the wiring. The Axpert is in a cottage which is off grid on sunny days (solar geyser and electricity). I am still working on Sonoff POW switches and Openhab smart home software to see if some other loads can be added without overloading or draining the battery.

What I have discovered is I had to Install a separate 12 volt lighting system as backup for when the Axpert shuts down on low battery.

what?

also you should take their claim of unbalanced phases seriously imo...

 

[Geoff.D]

what?

also you should take their claim of unbalanced phases seriously imo...

Agreed! It is in your interest to balance the phases on a 3 phase feed. You are exposing yourself to fault currents when things go wrong. And to boot, they could come along and demand that you fix or lose your power connection.

 

[russellw1]

what?

also you should take their claim of unbalanced phases seriously imo...

I need more than 2kWh of battery power, maybe 2 more lithium batteries because 1kVA or about 700 Watts is the limit for 2 hrs.

On the unbalanced loads Eskom themselves have discovered that their line voltages only just make the 20% spec because one phase usually is at 240V and the other 2 are at about 218V. Their main problem was that our solar geyser and the Axpert inverter have reduced the billing by +- 400 kWh per month. They thought we might be exporting power to the grid but the Axpert can't do that. We just got a free data logger spreadsheet tor 3 weeks of our power usage and it shows that the phases are balanced except when the geyser timer or stove is switched on.

I also tested the dry contacts and I see the recomrnded use is to drive an earthing box which has another relay to connect neutral and earth for the db box earth leakage safety circuit to work. It could do LEDs at the same time.

 

[russellw1]

I
I2R

Agreed! It is in your interest to balance the phases on a 3 phase feed. You are exposing yourself to fault currents when things go wrong. And to boot, they could come along and demand that you fix or lose your power connection.

Eskom gave us the data logger spreadsheet tor 3 weeks of our power usage and it shows that the phases are balanced except when the geyser timer or stove is switched on. Only the monthly total units is a lot higher on some phases.