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Ingo avatar image
Ingo asked

Another Inverter Overload with ESS question

For some time I've noticed my inverter give overload warnings. On investigation I found that if my load exceeds the inverter capacity, let's say 5000W then I have an overload warning even when the grid is connected and solar producing power.

My configuration is:

Grid Connected

Quattro 5K, 481

RS450/100 producing +-3000W

Load +-5000W

Battery supply remaining +-2000W

Grid supplying some watts, minor values though.

Both ACOut1 and ACOut2 in use as per normal No Grid Failure scenario.


Why would the inverter give an overload warning when it's maxed out on Inverter power but the connected grid is still connected to provide 'top-up' when needed?

We all know the inverter is at max so while the grid is connected I don't really care. When the grid is NOT connected then YES, then I need to know about it. Can that setting not be amended to not warn me on a daily basis that my inverter is working hard for it's money?


Ingo

MultiPlus Quattro Inverter Charger
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3 Answers
Alexandra avatar image
Alexandra answered ·

@Ingo

A warning is just that. You know you are pulling more than the inverter can invert. It is a warning and in the even of grid faliure it will become an alarm.

The inverter will be trying to carry the whole load if you have set the grid set point down as well and be trying to power assist so working hard.

Have you set the max inverter power in the ess menu? on a 5kva set it to around 4000 or alower if you are in a hotter area. I have seen is make a difference in any case to the warnings. Still get them though.

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Ingo avatar image Ingo commented ·

Thanks @Alexandra I thought of setting the limiter to 4000 but then decided against it. My thinking is: Let the inverter run full taps, it's built for that and why hamstrung the unit down to a smaller value.

The warnings, while grid-connected, just seems pointless to me in this situation as I am not going to lower the load on the inverter. If it needs more power it will just import power from the grid - which I am fine with.

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marv21 avatar image
marv21 answered ·

"The warnings, while grid-connected, just seems pointless to me in this situation as I am not going to lower the load on the inverter. If it needs more power it will just import power from the grid - which I am fine with. "

Thats my thinking too. Iam in the same Situation. Getting spammed with "Overload" Warnings. Its annoying that the Inverter themselfs drive themself that hard to get this Warning. I now just disabled it the Warning. Somewhere I can understand that a Warning is not an Alarm, but ON-Grid its just useless to have it, if there is no Danger ahead.

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ejrossouw avatar image ejrossouw commented ·
Are you using ACOUT for loads? Do you require an essential load function?
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Ingo avatar image Ingo ejrossouw commented ·
@ejrossouw I don't know about @Marv21 but I use ACOut2 for heavy loads and ACOut1 for Critical loads. When the grid/solar is connected it supplies power to both which is 100% in line with the design of the unit.
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marv21 avatar image marv21 ejrossouw commented ·

I have everything connected to ACOut1.

Therefor in an Offgrid Situation i have to care not to switch on to many heavy loads.

I see the Warnings more like a "Hey, care. If you switch to off-grid now (Power outage) then i will shutdown." now. But i shut them off.


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shaneyake avatar image shaneyake commented ·

I like having the warnings because it is letting you know that the inverter is limiting because it is getting too hot. If you increase the cooling or lower ambient temperatures you can get a few more watts out of the inverter. Warning is just there to say hey, I had to reduce power because things were getting hot. You can see the warnings on VRM without getting notified.

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Ingo avatar image Ingo shaneyake commented ·
It's the middle of winter here and the temperature of the inverter is around 10 degrees C.

I think the issue is not very clear. The Inverter is connected to the Grid, it's not overheating and there is nothing wrong with pulling say 10KW from a 5KW inverter when connected to the grid - it's designed to do that.

Why would I then get an Overload Warning if the grid supplies 5.5KW and the inverter 4.5KW? Or better yet, Max from Inverter and the remaining from the Grid. If I increase load to 15KW then the Grid just supplies more, the Inverter stays at Max power as designed - it should whine about it unless it's connected to Battery only..

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shaneyake avatar image shaneyake Ingo commented ·
But that is not how the inverter works, the inverter will ramp up and cover the full 10KW, once the internal temperature or current gets close to limit, it will reduce its output to 4.5KW or whatever the cooling allows.


If you put on a load of 15KW it will ramp to 10KW as that is the max peak.

This is also my preferred behavior as it does some peak shaving for loads with high start up current.

You can set the inverter limit to 5kw or 4.5kw and then in theory it should only ramp to 5kw and not give the warning. However that controls the GX and will take some time to respond.

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Ingo avatar image Ingo shaneyake commented ·
I don't think that is correct when Grid connected. You are describing the behavior when on Battery only. When Grid connected it 'blends' the Grid and Inverter power as to add 4.5KW of inverter power to whatever the Grid is supplying. If I up the load to 20KW it should still supply 4.5KW from the batteries/solar and 15.5KW via the Grid feed in but you get my point, right?
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shaneyake avatar image shaneyake Ingo commented ·

This is effectively true and if averaged over the time is the case but the internal inverter control doesn't work like that.

The way victron inverters work is that there is a grid setpoint, this is the power that is coming in on AC IN, the GX then sets that to some number, like 0W to run ess or -200W to export, +200W to import.

If you are using a grid meter and the load is parallel to the inverter, the GX will set the grid setpoint as setpoint = ESS_grid_setpoint- GRID_meter_power, this is sent to the inverter every 5 second or so.

The inverter then internally and very quickly keeps the AC INpower at that number. If you turn on a 2kw load, the inverter quickly ramps up to met that load, there is a max ramp rate to keep the inverter stable. When that load turns off it will quickly ramp down. Now when you turn on a 20kw load the inverter is still set to 0W of AC IN power, the inverter will ramp up and while ramping it will hit the max internal current limit, this is at 10kw for Quattro 5kva, the AC IN power will now read 10kw as the Quattro is only making 10kw, the inverter still wants to ramp up but the protection system is now preventing that, after a few second the internal current limit will be lowered to some power and the inverter will ramp down, this might not trigger the warning but probably will as current is close to limit.

Lets say the inverter is now running at 6kw, the fans start spinning and the heatsink starts to heat up and the inverter will start to de-rate itself and keep the inverter current just below the max, this will hold the inverter in warning state.

Same happens when exporting, GX will say setpoint to -10kw inverter will ramp up, it will hit current limit and heat up and then de-rate. This happens because inverter is trying to produce the 10kw to feedback but there are other systems like internal current limit and internal thermal limits which are reducing the inverter output.
When any of the limits are active that is when the inverter reports a warning.

Does that make sense? You can set your grid setpoint on your GX ESS setpoint to -10 000W and watch your inverter go into warning after a minute or so.

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Ingo avatar image Ingo shaneyake commented ·

Ok, that explanation I can agree with. The issue is that there is no real purpose in producing a warning message in that situation. If I draw 20KW and the inverter is at max, everything heats up and start to derate a bit, it's not going to make me turn off the 20KW load. The warning is just informational actually.


What I am saying is that perhaps make that particular overload warning message either 'selectable On|Off in the GUI' OR don't warn me at all while On Grid. Every time I open the remote console I have a flashing message and I HAVE to go and see what it is just in case it's NOT the overload warning - it gets tiresome and I am now ignoring all messages at the moment with the chance I miss an important one.

Edit: I set my Overload setting to Alarm Only so won't see these any more. But I fear If the rest of the house does the 'Kettle and Hairdryer' thing then perhaps I might be in a bit of a pickle when running on batteries only. Time will tell...

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shaneyake avatar image shaneyake Ingo commented ·

Okay, I see.


On your "Kettle and Hairdryer", you can add a buzzer to the K1 output on the Quattro and set it to tigger if you get a pre-overload alarm using the assistants, can be set to only happen when no grid. I have this setup in the center of our house so that if you overload the inverter while there is no grid you know to quickly turn off the thing you just turned on. Less of a problem now that I am running 2x inverters.

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Ingo avatar image Ingo shaneyake commented ·
Will investigate that option, thanks.
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marv21 avatar image marv21 shaneyake commented ·
Yep here is summer, but the Inverter is around 19°C. I think it is not to hot. The Warnings appear as soon as i heavy load is switched on. In my Opinion the Warning should only accour if the Shutdown of the Inverter (Alarm) is close ahead. But i can have a warning for hours. It will never Shutdown. On the other Hand i can see the upside of that. If you get a Warning it means "Hey, care. If you switch to off-grid now (Power outage) then i will shutdown."



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shaneyake avatar image shaneyake marv21 commented ·

I don't disagree, it is a nice warning, however you can get it with the load in parallel to the inverter. So happens even if the load is not on the inverter output. Which would not be connected if grid was lost.


On the "inverter is around 19°C. " Yes, the outside temp is 19C but the heatsink temp can me much higher, I have had my inverter push out air that is hotter than 65C.

I would just say don't worry about it, the inverter knows what it is doing, you can turn off just inverter overload warning on your GX if you would like get notified about all the other warnings.

If you have unstable grid, you can also get overload warnings if the inverter doesn't respond quickly enough to change in grid voltage.

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dcsonka avatar image
dcsonka answered ·

Hi,

I wrote a doc on my experience with similar issues. See attached.

Limit inverter power.pdf


limit-inverter-power.pdf (345.7 KiB)
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