Reading data sheets - do I understand correctly?

So currently I have a Goodwe ES 4.6kW. I found out early on that we could overload this system. Usually at breakfast time. Toaster + microwave + kettle would often do it.

Looking at the datasheet and if I understand it correctly, it supports peak loads of 9.2 kW whilst the grid is available, but only 6.9kW when there is no grid. This explains the occasional overload we still get.

But OK… what about the alternatives?

If I look at the 5kW sunsynk it says peak “off-grid” is 10kW. IE (if I understand correctly) it can deliver 10kW in short bursts with no grid. It doesn’t give 2 figures like Goodwe do.

So do I understand correctly?

  1. Goodwe will allow only 6.9kW when the grid is down?
  2. Sunsynk will allow 10kW when the grid is down?

If so, that’s a significant advantage to the Sunsynk. I’d have a lot more headroom. It can also charge faster (125A v 100).

This is not correct.

The inverter can only supply its Full rating when the grid is off. Even on grid with the Sunsynk, its recommended to limit the Input and Output breakers to 25Amp although the passthrough rating for the inverter is 32A. 32/4= 8kw. So the sunsynk can handle 8 kw constant with the grid available to support it.(Again, claimed but not recommended)

I will not install a Synsynk 5kw in an installation requiring 9kw loads.

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Thanks for clarifying. But you can see how somebody who is doing some shopping/googling can think that that is what is being claimed.

Of course the manufacturers are not all going to present the data in the same way, or all use the same definitions and the same ways of measuring. There is no standard they have to adhere to.

Or is there? Appliances sold into the EU all bear efficiency ratings that are based on a stipulated set of measurements and outcomes.

It won’t pass through 9.2kW. It can take that much from the grid when you are charging at the max rate, as well as passing through 4.6kW. I think it can do 6.9kVA for very short bursts, under a small set of circumstances.

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Are you overloading when it is loadshedding? If so, maybe just wait for the kettle to finish before you start the toaster? :wink:

Must say, if you run the inverter into overload, then get a bigger one, I bet the bigger one will also run into overload. :smile:

At least, that is how I figure out my family.

Where does one draw the line?

Cause a bigger inverter inevitably means a bigger battery which inevitably means a bigger array.

Just does not stop.

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For me, the latest line I am drawing (in the process of building my new power station), is such that if someone forgets, it should not cause a trip.

Example: Someone turns on a hair dryer while downstairs another person is making a cup of coffee. A cold long-haired house animal heats a bean bag in the microwave, not realising the power went off and the dishwasher wasn’t quite finished. The one-at-a-time rule can be problematic when at least two people can be doing different things in different parts of the house. It is however completely okay to assert that rule per person.

Will I move the goal posts again? Maybe… who knows.

Adding to that, the longhair hairy knuckle-dragging "alpha’ males in my house … the circuit breakers in the DB sorted trippings quite nicely.

All I know is a 63a breaker in a DB, that stops the above specimens from causing “havoc”.

Dang man, house above, they sat the whole day with no power. In the end, they accidentally checked the critical loads DB. It was tripped.

“Someone” switched on too much. Me, like smiling from ear to ear. Nary a bother for me nor the 5kva.

Check what you switch on buggers. I’ve got your ticket in hand, don’t make me punch it for you. :smile:

EDIT: Context. We have 3 separate parts in the house now … it gets complicated, in that who knows what who does. Critical Loads DB keeps them all in line, the dedicated pugs work lekker. Of course, there are extenuating circumstances … you just have to get past me to get to them.

You sure about that? That’s the size of my main breaker. My essentials are limited to 32A by a breaker, but a breaker doesn’t trip the moment you exceed the limit. It takes several minutes, it only trips immediately on 5 times the rated current. Which means, an inverter overloads far quicker than a breaker trips.

I’m speaking here of the usual C-curve breakers you buy at the electrical wholesaler, but I’m pretty sure even a B-curve isn’t going to save you.

Unless you go overboard and factor that in, put in 5A breakers or stuff like that so they trip quickly. But I don’t like that, which is why I use Sonoff POWs to police power where necessary. Faster, more accurate, and HomeAssistant can log the event too.

Jip, the main DB can mostly contain it.

Critical Load DB has a 20a main breaker.
Due to the cost of 5a breakers, I chose 10a per circuit max to avert nuisance tripping.
So far the inverter has never switched off …

More to think of, keep running. Less can sometimes be more … for me at least.

Goodwe say 10 seconds

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LOL. It was the Kettle (with somebody else driving) that pushed the system into overload. SEMS shows a load just over 6kW, and I can’t figure out how we got there. Pool wasn’t running because of load shedding, heat pump was turned off by the timer. So kettle, dishwasher and washing machine are what I know about that are significant.

Dishwasher might have started heating water. Washing machine is supposed to run on a cold cycle, but it sets water temperature automagically when you select the mode and then it’s up to the driver to reduce that. So maybe…

Not maybe, definitely! The system overloaded.

This used to happen a lot, with people getting carried away in the kitchen at breakfast time. So I introduced “the rule of three”. Should be the “rule of two”, because it says that if you have two things on in the kitchen (EG toaster and microwave), you wait for one to finish before turning on a third, EG the kettle. But you can’t expect people to wait for the dishwasher to finish before they have a cuppa.

It’s all ideological. I say “well, OK, so all that stuff is on and you want coffee. We have a gas stove!”. This is responded to with a lecture about how gas costs money whilst electricity, for us, is free.

On the plus side, I found an undocumented feature for our dishwasher and washing machine: They remember what they were doing when the power went out, and they restart at that point in the cycle. Our old dishy didn’t do that, and I asked the sales person about that feature for the washing machine and she said “only the top loaders do that”.

Well this is it. For a long time I was preaching that “solar” is not the same as “free and unlimited”. Then everything settled down and I stopped gaaning aan so much. And now we have backslid.

Plus, and it’s well intentioned, there is an impulse to save every cent. So why put the kettle on on the gas stove and burn a few cents worth of gas when you can use free electricity?

Well all this started because I want to upgrade my panels. I’m already marginal on overcast days, and our grid voltage is getting so bad (160-ish after restoration this morning!) that I can no longer bank on topping up from the grid because half the time the inverter is refusing to have anything to do with City Power.

We’ve done a lot of education at the house. But it is also why I like a Victron system. It seems to be REALLY forgiving. My 5kVA Multi easily carries us through, even when overloaded.

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That was Tuesday for me. Load shedding. Vacuum cleaner is running in the distance, but the lights are a little flickery so I get up to take a look. 3kVA Multi is happily doing 3.4kW, with the washing machine heating water at the same time. The overload LED is blinking, but I’ve learned that that is nothing to worry about. When the temperature LED starts blinking, that is when you have to start worrying.

Human nature.

I put in a Carlo Gavazzi, inverter shall not run the whole house … and split the boards. When LS, the really big stuff is off. Stuff that will cause me to have to look for overloads etc. My jippo, I can plug the front loader washing machine/dishwasher into a proper thick lead … if I must. Mostly I don’t feel the must anywhere close.

Toploader, bleh, it must maar run, it uses cold water.

Kitchen, have special plugs there too.

With forced manual intervention I forced people to look, think, and consider. But as you say, it does slip now and then.

My main goal was to run as close to 24/7 as I could … not how to run the inverter hard. That is what Eskom is for. And IF Eskom is off for a while … we can manage quite nicely. 5kva gets you moer far.

Just look at Plonk and how far his 3kva gets him.

For us, during the high loadshedding stages we had in summer, I often had my “doomsday switch” flicked, i.e. all my non-essentials on the inverter as well. Things could then continue as normal. So, everybody in the house is well trained on kitchen and other resistive loads. Our helper is also very conscious of the vacuum (luckily ours is only about 700W).

But still, when the geysers come on and our timing is a bit off on when the scullery will finish, or we forget about loadshedding (happens frequently), things can get dicey. I’ve had 6kW+ out of the MP which we only realised later when looking at data, because we heard or seen nothing.

Actually, the fact of the manner is our Multi has NEVER tripped on overload, except once when there was a short circuit, which is obviously a good thing. It has been overloaded, accidentally, but never tripped.

During the height of stage 6 shedding, I had a bit of a timetable dance with the tumble dryer. You see, if the tumble dryer is stopped halfway, my kids’ school uniforms creases, and they do it so badly that you have to rewash them to get the creases out. That meant you had to get all the laundry washed and dried before load-shedding hit. And a few times, I got it wrong.

The tumble dryer actually doesn’t use that much energy. Well, yes it does, but nothing close to a geyser and my pool pump actually uses more (lower wattage, but constant over 4 hours). A tiny bit more peak power, and I can even run the tumble dryer on the inverter (obviously, I intend using an alternate plug scheme, I’m not going to wire the laundry to the backup power). That was really the only thing I missed with the 3kVA. It really gets everything done, as long as you are stage 4 or below.

That, and the occasional accidental double hit, where two appliances accidentally come on at the same time. The 1.5kW “Prism” water heater under the kitchen sink is another little bugger that surprises you sometimes. It makes only 15 liters of hot water, and it reheats it quickly. Brilliant for a kitchen, no waiting for hot water to arrive, no water wastage. But on a 3kVA, when you are doing lots of other things, you sometimes have to drop it, and then you lose hot water.

Minor annoyances, but I think @jykenmynie has a point: A 5kVA really gets you just about everywhere you need to go.

The ONLY reason I upgraded my 3kva to a 5kva, was because of temp … it derated to 1700w in summer feeding the house.

I could have made it run cooler … but I got that “I WANT I WANT” feeling. :slight_smile:

Just control the usage now and then … we are 7 Adults living on site now, and 4 work from home.

As you say: A 5kVA really gets you just about everywhere you need to go.

Ps. We also have a dryer, but all being adults: $*&#&!!! The sun was shining the whole week!!! Forget it … or gooi some units towards your problem. $&#^#!!!

Works quite well I tell ja, for adults. Kids, different story! We babysit on weekends, so I know. :slight_smile: