Hi all,

My system is hybrid, but most days we buy only a small amount of power from the grid, and the numbers and graphs I get from SEMS portal lead me to think that my system actually has capacity to run our entire property on a sunny day. 

Now a while back, when I was bored, I used the app on my phone to put the system into off-grid mode. Straight away my pool pump turned off. The pool pump is not on the backed up circuits, but clearly (or according to SEMS portal) on a sunny day the pool somehow does run from solar power. So there must be a way for the Goodwe to send some power to the non-backed up circuits.

So how can I try running the whole property? Do I need to do something* other than put it into off-grid mode? Is this possible?

* something that doesn't involve an electrician (which I am not)

Mine does a similar thing when I switch my geyser element on. Even though the geyser is not connected to the system, the inverter will use battery+solar+eskom for it. The only way I've been able to go completely off grid is to switch my eskom mains off. However, the geyser element cannot be switched on unless I put the eskom mains back on. I think that the inverter is clever enough to realise it can "assist" non-backed-up items but unless those things have eskom to start up it cant do anything. Sorry I know this isn't the most helpful but perhaps an extra data point can assist you.

54 minutes ago, Bobster said:

So how can I try running the whole property? Do I need to do something* other than put it into off-grid mode? Is this possible?

Well, you would have to have all your circuits pass-through the Goodwe. Not sure if rewiring is allowed to be done without an electrician.

Not sure why you would want to "go off-grid" if you have a hybrid inverter. You'll already be feeding back excess solar power/battery power and you should just play around with settings and scheduling to get your grid import down to zero.

The only downside of doing it this way is that when the grid is down, your non-essentials won't be running, but that is really not too crucial, right? When the grid is back up, they would again be fed by your PV.

1 hour ago, Bobster said:

 The pool pump is not on the backed up circuits, but clearly (or according to SEMS portal) on a sunny day the pool somehow does run from solar power. So there must be a way for the Goodwe to send some power to the non-backed up circuits.

@pranam has it correct with the inverter being clever enough 🙂. In essence the inverter is taking the extra solar energy and pushing it back into the main incoming Eskom line, but because you have the pool pump etc. running the power goes there first... if you have lots of power being used then you use it all up at your house. If you are producing lots of extra solar and you have only a little load then all of the extra goes back up the eskom line, to the neigbours etc..... your pre-paid meter does not like this happening...remember 🤬.... and without permission is illegal..... so to prevent all kinds of issues you tell the inverter to not export at all. So it keeps on checking the loads and either opens or closes "the tap" from the solar side so that you do not have power going out to the neighbours etc. but when there is extra solar available it will add power to what is being used on your property (even if not connected to the backup side). If you chose to, and have permission, to "export", depending on how you set it up the inverter will still use the extra power for you, and whatever is left, if any,  will then go out to the neighbours (and reduce your electricity bill because technically now the municipality is buying electricity from you).

As a safety feature though, when Eskom is not available the inverter has to stop sending power to anything that is not on the "backup side" (it actually has to physically disconnect). If the municipality switches off the power to work on the transformer down the street but your inverter and solar is sending power back up the line the poor bloke working on the transformer does not have a way to know there is still electricity heading towards to him. That is why the pool pump stops when you use "off-grid" mode  - you are cutting off the pump's electricity supply... even though the pump is connected to the inverter but it is connected to the non-backup side to alow you to use solar as much as possible to reduce the pump related electricty bill.

1 hour ago, Bobster said:

So how can I try running the whole property? Do I need to do something* other than put it into off-grid mode? Is this possible?

* something that doesn't involve an electrician (which I am not)

As pointed out by @jykenmynie you will in all likelihood have to have some circuits (DB wiring) re-wired (keeping in mind total load, rating etc. of the inverter).

There is something else to keep in mind. If everything is set to run from solar and the pool pump is set to start at 09:00...solar is not producing much yet but now the pump tries to start.. the extra power will have to come from the batteries. Even if nothing else is running and the solar conditions are near perfect, there are still limits as to the size of load that the inverter can start - especially things like motors that have a very high inrush current.

19 minutes ago, introverter said:

there are still limits as to the size of load that the inverter can start - especially things like motors that have a very high inrush current.

This is the probably biggest stumbling block if you are going "off grid" and not just going the "cheap" route of having the grid provide the first few seconds of your inductive loads' startup, which is possible with a 5kVA Multiplus II. Then you can just put all your non-essentials on AC Out 2 and the essentials on AC Out 1.

Going "off-grid" with a Goodwe will require a really careful configuration of your house and probably require another Goodwe or two. The wiring will be a mess because you can't parallel the inverters. You'll probably end up with three separate "mains".

Doing this with Victron is a whole lot easier, because the inverters could be put in parallel (or just can just go balls to the wall with the 15kVA Quattro).

3 hours ago, Bobster said:

Straight away my pool pump turned off

that is strange. If the pool pump is directly wired to Eskom (as you say) then disconnecting the inverter from the grid ("off grid" mode) should have no effect on the power supply for the pump. I can not think of a wiring set up causing the problem you describe. Even if the pump were on the back up output it would still be running if you isolate the inverter from the grid.

3 hours ago, Bobster said:

So how can I try running the whole property?

you would have to rewire the DB and connect everything to the back up output of the inverter 🙂.

15 hours ago, Fuenkli said:

you would have to rewire the DB and connect everything to the back up output of the inverter 🙂.

Which is what I suspected, but also what do I know? That clearly isn't going to work because the 20A limit is sufficient most of the time, but there will be spikes past that which will trip the Goodwe.

It's also more than I want to do myself. Well, not more than I want to, but more than I know I can do safely and properly and without burning stuff out and replacing it.

Edited July 9, 20206 yr by Bobster

15 hours ago, Fuenkli said:

that is strange. If the pool pump is directly wired to Eskom (as you say) then disconnecting the inverter from the grid ("off grid" mode) should have no effect on the power supply for the pump. I can not think of a wiring set up causing the problem you describe. Even if the pump were on the back up output it would still be running if you isolate the inverter from the grid.

I didn't say it was wired directly to grid. I said it's on the non-backed up circuits of the Goodwe. Indeed, at times the Goodwe is clearly sending excess power to the pool pump and other non-essentials.

16 hours ago, introverter said:

There is something else to keep in mind. If everything is set to run from solar and the pool pump is set to start at 09:00...solar is not producing much yet but now the pump tries to start.. the extra power will have to come from the batteries. Even if nothing else is running and the solar conditions are near perfect, there are still limits as to the size of load that the inverter can start - especially things like motors that have a very high inrush current.

I have two arrays of 6 panels. One faces East(ish) and so generally by 9 I have quite a bit of solar power coming in. So my power curve is perhaps atypical and peaks at about 11:30. So I can turn my pool on at 9. But I take your general point, indeed have taken it and tried to move what loads I can control around to take advantage of solar power.

My first adventure with non-grid power was a solar geyser, and I learned that to make optimal use of it we in the house had to change our behaviour to literally make hay whilst the sun shines (or has just finished shining). It's no different with my current system.

16 hours ago, introverter said:

@pranam has it correct with the inverter being clever enough 🙂. In essence the inverter is taking the extra solar energy and pushing it back into the main incoming Eskom line, but because you have the pool pump etc. running the power goes there first... if you have lots of power being used then you use it all up at your house. If you are producing lots of extra solar and you have only a little load then all of the extra goes back up the eskom line, to the neigbours etc..... your pre-paid meter does not like this happening...remember 🤬.... and without permission is illegal..... so to prevent all kinds of issues you tell the inverter to not export at all. So it keeps on checking the loads and either opens or closes "the tap" from the solar side so that you do not have power going out to the neighbours etc. but when there is extra solar available it will add power to what is being used on your property (even if not connected to the backup side). If you chose to, and have permission, to "export", depending on how you set it up the inverter will still use the extra power for you, and whatever is left, if any,  will then go out to the neighbours (and reduce your electricity bill because technically now the municipality is buying electricity from you).

Thanks. This completely explains what I am seeing.

@Bobster, is the 20A limit purely battery or in total (battery + panels)? If you're able to get 20A from the battery plus say 10A from your panels with good light are you not safe in 99% of situations?

26 minutes ago, Bobster said:

I didn't say it was wired directly to grid. I said it's on the non-backed up circuits of the Goodwe. Indeed, at times the Goodwe is clearly sending excess power to the pool pump and other non-essentials.

Hi Bobster

Your Goodwe shouldn't have two "Outputs" like a Victron. It only has out "Backup Output". In order to power the other non-essentials, it pushes back on its AC In. So yes, it is powering the non-essentials, but it won't power them if they don't already demand power from the grid. Your EZ meter tells the Goodwe that those appliances are demanding power from the grid and then the Goodwe pushes back to neutralise that draw.

Just now, pranam said:

@Bobster, is the 20A limit purely battery or in total (battery + panels)? If you're able to get 20A from the battery plus say 10A from your panels with good light are you not safe in 99% of situations?

The Goodwe can only invert 20 Amps. Meaning, all its DC sources, PV included, it would be able to invert 4600kVA to AC. It does have a higher pass-through though, I think about 40 Amps (depending on the model). So from its AC Input, it would be able to transfer up to 40 Amps to its back-up side's AC demands.

27 minutes ago, Bobster said:

I didn't say it was wired directly to grid. I said it's on the non-backed up circuits of the Goodwe

if the pool pump is not on the back up output then it is wired directly to the Eskom grid supply. The inverter is running parallel to the grid and has no effect on the pump supply if it is going into islanding mode.

49 minutes ago, Bobster said:

It's also more than I want to do myself. Well, not more than I want to, but more than I know I can do safely and properly and without burning stuff out and replacing it.

These days I have quite a few jobs that are in that space of "I can do it myself, but it will take twice as long as if I hire a sparky/plumber". When it comes to marriage and the sensitive matter of water and electricity... just get the sparky to do it. It's an investment in your marriage. The job is done faster and you stay out of that space where you get blamed because you wanted to do it yourself and now it is taking longer...

Just yesterday I got a plumber to plumb in a water tank. Why? Cause he got it done with 30 minutes of downtime... at which time the wife was already getting impatient as her morning shower was being delayed 🙂

Edit: Honestly, I've actually worked on a live DB once because I wasn't in the mood for explaining why the power is down again...

 

Edited July 9, 20206 yr by plonkster

19 hours ago, Bobster said:

Straight away my pool pump turned off

maybe the neutral supply for the pool pump is wired to the back up output of the inverter? But if this is the case then the RCD should trip under normal operation. 

6 minutes ago, plonkster said:

These days I have quite a few jobs that are in that space of "I can do it myself, but it will take twice as long as if I hire a sparky/plumber". When it comes to marriage and the sensitive matter of water and electricity... just get the sparky to do it. It's an investment in your marriage. The job is done faster and you stay out of that space where you get blamed because you wanted to do it yourself and now it is taking longer...

Just yesterday I got a plumber to plumb in a water tank. Why? Cause he got it done with 30 minutes of downtime... at which time the wife was already getting impatient as her morning shower was being delayed 🙂

Edit: Honestly, I've actually worked on a live DB once because I wasn't in the mood for explaining why the power is down again...

 

Except when your wife's dad is one of those old school engineers and always did everything himself. Now you go around getting people to do stuff for you because you don't feel comfortable working on things you aren't even an amateur in... "I think my dad thinks that we are spending a lot of money of people to do these things for us when we can do it ourselves." 😅

 

4 minutes ago, jykenmynie said:

Except when your wife's dad is one of those old school engineers and always did everything himself

Or if your own dad was a farmer... who had to do everything himself.

It's actually funny, because my wife does like to brag about it sometimes. One day at Church she was explaining to another lady that she had to go, we had to swing by the hardware store to get a new thermostat for the geyser... (it had failed on a Saturday evening... as they do)... and this lady asks: Your husband can do these things? Shouldn't you rather call an electrician?

So anyway, these days it kinda goes both ways. Depends how quickly I need it done 🙂

 

That also explains why everything on a farm if fixed with a bit of baling wire. The logic is either a 50km round trip to Magalies, where they may have what I need, or 120km to Kdorp or Rburg, or what do I have handy? Here we go, baling wire, sorted! (for the moment).

4 hours ago, Bobster said:

Thanks. This completely explains what I am seeing.

@Bobster even though not said by @Fuenkli my explanation of the pump turning off is completely wrong (no getting away from it so I should man up).

If the pool pump is not on the backup side of the Goodwe then the eskom power going to the pump does not run through the inverter, so even if physically removing all wires from the inverter the pool pump should NOT switch off while it is running.

Out of interest, how did you confirm the pool pump stopped? I am sort of hoping the pump is wired on the backup side, you stood in the kitchen/lounge, flipped the switch on your phone, and the pool cleaner stopped moving because without the extra pass through from Eskom the pool pump dropped out and was just sitting there humming, and with the pool looking calm you deduced, the pump was completely inactive. I am even hoping for some Hollywood level happenstance that you flipped the switch just as the pump timer was programmed to turn off the pump. See how far I will go to try and save face....?😈  (very seriously though I am not underestimating your intelligence)

Anyhow, what you could do is with good PV conditions, almost no other loads and the pool pump running, turn off the main breaker in the DB (having to set the clock on the oven etc. is a small price to pay 😉), if the pump is confirmed to have stopped completely it is wired directly to the grid and other than energy saving from solar the Goodwe should have no influence over the pump. If the pump keeps on running or sits there making weird noises or the inverter trips on overload then it suggests the pump is in some way connected to the inverter.

4 hours ago, Fuenkli said:

maybe the neutral supply for the pool pump is wired to the back up output of the inverter? But if this is the case then the RCD should trip under normal operation. 

If setup as for the Aus/NZ grid code (no idea if it is even possible) would the RCD still trip?  

5 hours ago, plonkster said:

just get the sparky to do it. It's an investment in your marriage. The job is done faster and you stay out of that space where you get blamed because you wanted to do it yourself and now it is taking longer.

Good Priorities  

It's better if you can blame some else for the essential services.

2 hours ago, introverter said:

would the RCD still trip?

i think it would.  The normal (non essential) load RCD would have considerably different currents running in the neutral and live wires.