Hi,
It would be great if we have a prefailer or prealarm condition in Node-Red, so we have a chance to disable consumer (smart plug in example).
Example: I charge my car in case the battery is full. Sometimes the MP switch off because overheat or it switch off because overpower if someone else switch on a oven. In this case it would be great if I can switch off charging the car bevor the MP goes down.
Regards,
Rainer
Yes it can be done. I have smart switches in place on select loads that switch on and off based on load and other conditions
Sorry, but this ist not what I asked for. I need prefailure Messages in Node-Red.
The only thing 1 found was a battery voltage warning. And that was not as helpfull as I thought.
Okay. What brand car charger do you have? Another option would be to use a smart switch to read the power of the car charger and switch off before the inverter goes into overload/temperature or try and preemptively switch the car charger off. Edit: Or use battery voltage as the trigger
That is the real problem, how to detect overload and overtemperture. You get the error, when it is to late to protect from it.
How much buffer do you have before the inverter overloads? I have it so there is a threshold for certain loads
Overloading mostly happens when we switch on heavy loads. A greater Problem is overtemperture. This happens after we have a great load (2400 W) over a longer time (2-3 hours), and it depends on the air temperture.
You can read the MultiPlus Overload & Temp status from Node Red, that gives you “OK”, “Warning” or “Alarm”'.
Ok, this seems to be the right condition. Do you know how many time I have between warning and failure?
About half an hour if there is good air flow. But temperature rise also depends on ambient air temps, or it could be shorter.
Don’t forget you are also dealing with de rating.
I am assuming here your overload is actually a load within the inverters continuous inverting ability not peaking out of it.
What you are asking for is an interesting one based on load and not very predictable.
On temperature warning and temperature alarm it is possible then and probably more suited to your needs, (since you are already aware that the system is shutting down because of sustained high loads). The only other real fixes are air conditioning or larger inverter to compensate for derating.
That would depend on the amount of overload and temperature I guess.
If I’m not mistaken, a Multiplus can deliver 150% for let’s say a minute and 200% for a couple ten seconds. Maybe longer but let’s keep it safe, it’s never a good thing to push a device to its limits for too long.
Hard to make predictions on an overload condition as to how high the extra load will be and for how long.
You’ll need to tweak timing parameters to match your case but an overload warning for 10-15 seconds would seem like a good start to trigger load shedding actions.
If the car charging is your main load to be shed, you could consider adding a smart charging station (possibly from Victron) so it can throttle the car’s charger instead of hard cutting it with a relay.
If you’ll be load shedding with a relay, you could abuse the genset feature in Venus OS for that.
Configure a GX relay as “Generator remote start”, set generator start conditions based on Temperature and Overload warnings and then use the relay to turn large loads off and back on.
That way you don’t even need to build something yourself in Node Red since the feature already exists natively.
Another tip: with an assistant you can program an output relay on a Multiplus to activate when the internal fan is running and/or when a temperature or overload pre-alarm is active.
That relay can then be used to start an extra cooling fan.
Or you could use it to switch the AC Out2 relay.
If your large load (large pump, heater, car charger, …) is connected to AC Out2 instead of the main AC Out circuitry you can make the Multi switch it on/off dynamically without even having to use the GX.