Hi all

A few weeks ago I bought an Axpert King 5KW now on paper it has a lot going for it with the lithium bms connection(not working yet hopefully it will be enabled with the next firmware update) and the grid assist function 4Kw PV and can be paralleled. I went for the king as I liked the idea of the "grid assist" function. So that the grid can make up any short fall in solar production and have batteries for backup. However what I have noticed is when ever the grid is connected to the load even if its not actually supplementing at the time there is a constant 280W to 300W being drawn from the supply. this works out to roughly 7kwh per day!! Now this extra load doesn't seem to be going anywhere. the internal monitoring doesn't pick it up.Ive checked all this using a clamp meter on the incoming supply,outgoing supply and battery supply.2 days ago I brought this up with the reteller that i bought it from and they said "it must be a problem with the unit" and promptly gave me another one to test out.After changing the unit the same problem persists.The reteller came out to my house yesterday and confirmed that the installation is correct and to verify this extra load.He cant believe the extra consumption and suggested swopping it out for a Goodwe.So i find myself not using the grid assist function and instead run on solar/battery an off grid mode as such during the day and on bypass at night.which defeats the whole idea of the king.  Now i like the Axpert King and if it worked efficiently i would be very happy with it. Yes there are a few software issues at the moment but hopefully the firmware update coming soon will address these issues.The next step is the reteller the going to contact the local distributor to see if there is a fix for this otherwise its all going back and probably replaced with a Goodwe GW5048D  or possibly something blue.I assume due to the way the Goodwe's and the Victrons work this isn't an issue. Not sure if anyone else has noticed or having the same issue.

     

2 hours ago, RichieRich said:

constant 280W to 300W being drawn from the supply

280 W or more continuously would build up quite a lot of heat, I think. I suspect that you were measuring 280+ VA of apparent power, most of which was reactive. Reactive power just bounces back and forth between the inverter and the mains, not actually costing you any real power.

Do you have the ability to wire the AC-in to a plug so you can check the real power from a power meter? It would be interesting to know how much real power is being drawn.

Coulomb 

I haven't got a power meter.the best i can do is to switch off all the power not going through the inverter. take my electrictrical meter reading and reset the meters on my inverter. let it run in online (USB) for 5 or 6 hours with the solar isolated and see if there is a difference?

2 hours ago, Coulomb said:

apparent power

When the inverter is balancing the grid at zero the power factor hovers at really low values and that means the measured VA (which is what you get with a clamp meter) and the real power can be several orders apart. See below my EM24 meter showing a power factor of 0.05. That means even if a clamp meter measures 2A (which is 460VA), the real power is 23W.

 

@plonkster & @Coulomb thanks for your help.

So if there is a load say 450W, would expect to the same extra apparent power on top of  the load ? So 750W?

Ok so started a test at 12:30. Turn off the solar supply ,reset the energy monitors on the inverter and took a reading on my prepaid meter . so running for 1.5hours

Now there one thing that will throw a spanner in the works is that due to firmware issues when on grid power the battery will charge. But up to the maximum set limit  of 2A. so ill add 108w per hour to compensate. Ive also got ICC running and can see the battery charging since 12:30  at around 100w sometimes dropping to 50w for a short time then back to up 100w 

So far the reading are:

Prepaid meter : used 930wh

Battery charging : 162wh

Inverter load: 300wh

Differance : 468Wh missing ?

 

55 minutes ago, RichieRich said:

So if there is a load say 450W, would expect to the same extra apparent power on top of  the load ? So 750W?

Actually, no. They add vectorially, and they are at 90° to each other. So I'd expect about √(450² + 300²) = 540 VA.

That's another way to find out if it's real power or not. Real power will add normally; reactive power won't.

So after 18 hours the readings are :

prepaid meter 10.65Kwh

 Battery charge 0.75Kwh

inverter load 8.2kwh

Difference 1.7kwh 

So it’s not as bad as I thought at an average of 94w an hour. However is this a reasonable loss ?  How would a goodwe or victron setup fair ? 

I’m going to let it carry on like it is with the addition of solar and see how efficient the mixing of grid and solar is. 

Edited April 29, 20197 yr by RichieRich

27 minutes ago, RichieRich said:

So after 18 hours the reading are :

prepaid meter 10.65Kwh

 Battery charge 0.75Kwh

inverter load 8.2kwh

Difference 1.7kwh 

So it’s not as bad as I thought at an average of 94w an hour. However is this a reasonable loss ?  How would a goodwe or victron setup fair ? 

I’m going to let it carry on like it is with the addition of solar and see how efficient the mixing of grid and solar is. 

Well the proper way of knowing how much power your inverter uses is to look at its specs sheet.

Somewhere in a brochure or manual you will find a zero load power/self consumption number.

2 hours ago, RichieRich said:

So it’s not as bad as I thought at an average of 94w an hour. However is this a reasonable loss ?  How would a goodwe or victron setup fair ? 

Depends on what model. The older 3kw Multiplus had a no-load draw of around 35W. The new Multiplus-II  just 11W. I think the 5KVA model is around 18W. The Multiplus takes this from the battery however, not from the grid, though there are ways to make it take it from the grid instead.

I had the same issue - the 300w 'apparent' power usage of the Axpert.  Everybody tried to convince me it was just my efery meter that does not take the power factor into consideration.  My night time 'idle' draw on the efergy was around 980w.  I eventually got rid of the Axpert and now run a Goodwe and my night time power use is now 500 to 650w on the Efergy meter.  There was also a  rise in my municipal account when I had the Axpert running.  Granted I now export unused solar to the grid so can only compare to when I did not have an inverter attached.

EDIT: THis was the normal Axpert 4kw inverter not the King

Edited April 29, 20197 yr by pspspeed
added info

33 minutes ago, pspspeed said:

My night time 'idle' draw on the efergy was around 980w.  I eventually got rid of the Axpert and now run a Goodwe and my night time power use is now 500 to 650w on the Efergy meter

The Goodwe might just have better power factor?

The worst I heard was a pair of Infini-V models that drew around 200W together. The consensus is pretty much that the old Axpert's draw around 50W each, at no load.

6 hours ago, plonkster said:

Depends on what model. The older 3kw Multiplus had a no-load draw of around 35W. The new Multiplus-II  just 11W. I think the 5KVA model is around 18W. The Multiplus takes this from the battery however, not from the grid, though there are ways to make it take it from the grid instead.

@plonkster

how does this number change if you have a 20W constant draw, for example? I'm asking because I believe that 18W is for "load search" mode, but once there is even the slightest load, then the inverter has to generate a full sinewave. Therefore, I believe that the total consumption will be much higher than 18W+20W in that case.

Am I wrong?

2 minutes ago, Youda said:

how does this number change if you have a 20W constant draw, for example? I'm asking because I believe that 18W is for "load search" mode, but once there is even the slightest load, then the inverter has to generate a full sinewave. Therefore, I believe that the total consumption will be much higher than 18W+20W in that case.

In search mode it uses only 2W. In AES mode (which is a modified sine wave used at low power levels) it is 12W, and no-load draw is 18W.

But you are right that this is not the only penalty. The overall efficiency of the inverter varies according to how hard it works and can be anything from 60% at low power levels (because of the no-load draw) to 93% at just the right conditions. In my own testing I have found it to be around 88% efficient at higher power levels, especially when the fans are running.

On my 3KVA unit I easily lose 200W when it is working hard (running above 2kw).

At a constant 20W draw, I would in fact expect the total to be very close to the sum of the two, that is around 40W, or 50% efficient.

Today i ran on solar with the grid to cover the short fall from 7am till 3pm. Our total load was 11kwh and produced 7kwh with solar ,the grid usage was 4.9kwh .

So lost about 110w per hour during the day.

I wonder what the efficiencies are like on the solar side?

Edited April 29, 20197 yr by RichieRich

I suspect some terms are being confused here.  The AC load and the battery load have different values.  I can pretty clearly remember the Victron no-load on battery being close to 50w for the 5kW but maybe I'm remembering wrong.

But that was the AC disconnected and the battery being loaded to run the inverter.

The actual draw when it is connected to AC is a different thing altogether because at that point, the Axpert King is both running the inverter and charging the battery.  Unlike the Victron the Axpert King is double conversion, that is the whole selling point.  The cost of that is higher AC draw.  You can reduce that significantly by putting it into "eco mode" or something like that.  Then it will run in line interactive mode like the non-king axpert and Victron inverters.

To explain, the Axpert King is converting your incoming AC to DC and then back to AC.  It does this to provide a perfectly clean AC output (both sine wave wise and frequency wise) and also give you that 0ms transfer time.  But converting from AC -> DC -> AC does have a cost.  Another benefit of this, is your operating range is very wide, the input voltage IIRC is something like 110volt - 300volt AC without needing to switch to battery.

Edited April 29, 20197 yr by Gnome

6 minutes ago, Gnome said:

I can pretty clearly remember the Victron no-load on battery being close to 50w for the 5kW but maybe I'm remembering wrong.

The 18W above is for the Multiplus-II. The older Multis were a bit more, 35W on a 3KVA and close to 50 for the 5kva.

But in an ESS setup the inverter component is switched off when the minimum SOC is reached and then the draw is again considerably less.

9 minutes ago, plonkster said:

The 18W above is for the Multiplus-II. The older Multis were a bit more, 35W on a 3KVA and close to 50 for the 5kva.

But in an ESS setup the inverter component is switched off when the minimum SOC is reached and then the draw is again considerably less.

When was the Mutiplus II released?  I'm pretty sure it'll take the Axpert at least two years to catch up in that regard.  They'll never really be pioneering in the efficiency space IMO, every increase in efficiency has a significant component and design cost associated with it.

Edited April 29, 20197 yr by Gnome

13 minutes ago, Gnome said:

When was the Mutiplus II released?

About a year ago. But this is not a competition, it came up merely because someone asked how it compares.

13 minutes ago, plonkster said:

About a year ago. But this is not a competition, it came up merely because someone asked how it compares.

Haha, I'm not seeing it as a competition.  I'm more comparing how say a tier 2 inverter company would compare to a tier 3.  If that makes sense. 

IE> I would expect Victron (tier 2) to have much more money to invest and be more of a market leader than VoltronicPower (tier 3).  Neither compare to say SMA, LG, etc. which I would deem tier 1.

EDIT: Also everything in life is a competition.  The question is if you have a vested interest in the outcome.  To any consumer the answer should be that more competition is better.  But fanboys like to rain on that parade.  Partially because they made an informed choice and can't accept that others may have done the same.  #JustSaying.

Edited April 29, 20197 yr by Gnome

13 minutes ago, Gnome said:

Partially because they made an informed choice and can't accept that others may have done the same.  #JustSaying.

Yeah... I remember about 10 years ago I had the hardest time accepting that anyone could buy a BMW (with all the crap they give once they start breaking down). I simply had to accept that for some people, all that crap is worth the luxury 🙂

26 minutes ago, plonkster said:

I simply had to accept that for some people, all that crap is worth the luxury

And now it is Ford. 🙂 

18 minutes ago, The Terrible Triplett said:

And now it is Ford. 🙂 

LOL. Yeah even Renault... there was a time you would not touch that with a very long barge pole. But people who drove a scenic said it's a very nice car. I just couldn't get past the fact that replacing the timing belt practically required removing the engine, or that the electronic handbrake would cost R12k to fix when it breaks. That just boggled my mind. But today they are the third biggest car maker in the world... so they must be doing something right! Just not the things I value...

Similarly with those who drive luxury German sedans. That's the kind of guy who values Fahrfreude so much that he's willing to spend 200k a year on it. I'm not that guy. I pretty much try to avoid the pain that comes with having to send a car in for repairs AGAIN... I like cars that ask for one repair trip or less per year. And the same for my electronic stuff, preferably I want them to last for a bit.

About Ford: https://www.fin24.com/Companies/Industrial/watch-ford-under-criminal-investigation-20190428

Gets worse, for your pocket locally: https://www.news24.com/SouthAfrica/News/ford-drivers-beware-your-cars-locks-may-not-be-secure-20190425

12 hours ago, The Terrible Triplett said:

Gets worse, for your pocket locally: https://www.news24.com/SouthAfrica/News/ford-drivers-beware-your-cars-locks-may-not-be-secure-20190425

I actually saw the Carte-Blanche insert. I think in some ways it is totally overblown. So quick recap of what happens here.

1. Most cars now work totally using the central locking system, so there are no locks on 3 or even 4 of the 5 doors.

2. There is still a mechanical lock on the driver's side... cause if the battery goes dead, how do you get into the car otherwise (well... ask Tesla... 🙂 ).

3. Ford helpfully made this lock interact with the security system, so operating the lock also turns off the security system and opens the other doors... you know like Mercedes Benz'es of the 80s did.

4. This is a little different to most other cars. On other cars there is no such interaction. The lock opens the door. The alarm goes off. You have to put the key in the ignition to turn off the alarm.

5. I firmly believe these other cars without the interaction did that to save costs... not because everyone was so smart to think about security.

6. To get into cars, people break the locks. They do it with all cars.

7. On a Ford, there is now the slight advantage that you don't have an alarm that draws attention (on a Fortuner they simply unplug the siren and the horn before breaking in).

8. Suddenly everyone is all legal on Ford's arse even though technically their cars are no less safe than any of the others...

 

Edited April 30, 20197 yr by plonkster