Good Morning,
We run Self Catering accommodation in the Western Cape… We are getting Grid Tie inverters with Lithium batteries installed, but I am for seeing a problem, the LIGHTS and PLUGS circuits will be wired to the inverter and batteries…
These units are small so there is only 1 PLUG CB in the DB… Now, despite proper explanation and signage in the unit, guests could try to run the electrical kettle and toast a couple of slices of bread… Which will drain batteries in about an hour leaving them in the dark for the 3 hours remaining on our loadshedding schedule…
Any quick and easy solutions to isolate some plug outlets on a plug circuit, yet have them back on when the loadshedding session ends?
Thank you so much!
N
Set the Max discharge current on the inverter. It will trip and restart when the current gets to high.
Nothing like all the lights going out when the inverter is overloaded to stop it happening again!
Installed like 6a/10a breakers to stop like anything on that circuit/s exceeding the allocated wattage … with clear warnings.
Then installed a breaker over all the circuits that says: Thou shall not exceed the holy grail, being the 4kw I have allowed to carry. Breaker trips … not the inverter.
Hope this gives you a new idea.
I’ll tell you what I did.
I ordered a bunch of Sonoff POW Wi-Fi switches. Good luck finding any right now, this was a while ago. I see there are nice ESP32-based newer models, but they are somewhat costly.
Then I flashed them all with Tasmota. I believe this step is optional. It can also be done with the default Ewelink firmware.
Then I configured them with a power limit, and to switch off if this is exceeded for more than 5 seconds. My power limits are very low. They are for running a few lights, the television, and maybe charge a laptop. 250W is about the max needed.
I have one plug wired to the sonoff power switch. The other plugs go down when the grid is off.
This works perfectly for me, and the reason I did it this way, is because circuit breakers take a long time to trip. Your average C-curve breaker only trips instantaneously at 500% of its rating. In my case, I also wanted to prevent overloading of the inverter (which is shared with the main house and other guests). The Sonoff switch reacts within seconds, and also retrains the user in the process. It is programmed to restore power after 30 seconds.
Did you do that in Tasmota, or in NodeRed or something similar?
Tasmota. Look at the MaxPower command, and the additional MaxPowerHold and MaxPowerWindow commands.
I have not tried it with Ewelink, but scouring Youtube seems to indicate it can be done. So you don’t HAVE to go with Tasmota. I just did it because that’s what my Home Automation uses.
Well then don’t connect these plug points to the backup power…
Whilst staying at B&Bs recently I noticed that although there is some backup power during power outages for ‘essentials’ the hectic power devices don’t have power.