Solutions for loadshedding

[kosmonooit]

Kill switch aka transfer/bypass switch every system should have one.

 

Then the AC feed to the Inverter should have a two pole isolator

 

 And the feed back back to the main db should have a 1p circuit breaker of suitable rating (to protect the cable)

 

Not sure what the cb is the right of the transfer switch, one of the above?

 

In your combiner box, there is a fuse for each string? how many strings? I can see maybe 4 fuse holders, what is between them?

 

Generally one has a 1p DC CB for each string as well in the combiner box, useful for a number of reasons.

Edited February 19, 2021 by kosmonooit

[Karman de Lange]

I've recently spent some time figuring out how those Axpert/Kodak/Synapse type inverters - solar chargers, picking up stompies at various sites after customers realise they have been over promised and under delivered, Recently been looking very closely at one system that was installed with the promise 'it does everything' but no one knew was was going on and the supplier got the boot after wanting to charge R5k for a 'service' which was to wash the PV panels. I set up a PC with that Watchpower software and remote access, so been coming to grips with how it works (or doesn't work)

 

So from what I can figure out in the modes Solar-Batter-Utility or Solar-Utility-Battery.

 

The load will be powered from the solar providing the load is less that the PV power input. 

 

In SUB mode, the load will be switched back to mains when the load is more that the PV power, and the PV will charge the batteries. Battery power will be used when no mains/utility.

 

in SBU mode, the inverter will dip into the batteries reserve until the set voltage discharge level is reached, and then back to mains/Utility.

 

Looking at the daily data, what seems to be the effective PV power out to the system is total charging current, even though Mains is on, the solar charger puts DC power on to the bus, and the Inverter takes it from there to produce mains AC. This does not really correspond with the daily PV power graph, that is the issue I have trying to figure out.

 

The BIG limitation with these types of Inverters is that the PV power can not be combined with the Mains, so generally PV is not even used unless you manage the loads carefully.

 

I see these Axpert type products primarily as a backup system, its functionality is limited compared to Victron architecture, which I have worked quite a lot with. If I can give some advice, besides lithium batteries, is stretch the finances and get a Victron Multiplus if you want to set up a versatile system.

 

What Victron can do is synchronise its Inverter generated AC with Mains and 'combine' accordingly. Solar Chargers also feed power onto the DC bus as needed, but this is all managed by the magic of the Venus controller via various signal buses.

 

I've not seen any regs here about Firemans switches (besides power supply to an outdoor sign) but what I have seen is totally dodgy electrical work by just about every other installer here in Jhb (for clients who are paying top$ btw), particularly bad when it comes to separating boards into mains powered and standby powered sections, ie generally not done even remotely properly according to acceptable practices and SANS 10142 codes. Mind you that's been very good business for me sorting all those gemorses out.

 

I normally install a 4 pole bypass switch at the sub db by the Inverter system, Mains in and Mains Out feeds, so the system can be completely bypassed if and when there is an issue.

thanks

 

so in essence it runs off solar until to much power drawn (geyser/aircon etc) , switch back to eksdom.. and solar does nothing until load drops again.  (Yes, i run our aircons and geyser of solar )

.

was wondering how they make sure there is no feedback back to grid..  most other systems have external controls talking to the different inverters (solar/battery)..  its not easy to get rid of energy ..  

 

(Sma uses Home Assistant and Victron uses the GX with mostly Fronius grid tie to prevent feedback.)

Edited February 20, 2021 by Karman de Lange

[Frosty]

thanks

 

so in essence it runs off solar until to much power drawn (geyser/aircon etc) , switch back to eksdom.. and solar does nothing until load drops again. (Yes, i run our aircons and geyser of solar )

.

was wondering how they make sure there is no feedback back to grid.. most other systems have external controls talking to the different inverters (solar/battery).. its not easy to get rid of energy ..

 

(Sma uses Home Assistant and Victron uses the GX with mostly Fronius grid tie to prevent feedback.)

The panels don’t always generate full power all the time. If the demand goes up, and the panels can generate more, they will.

[Frosty]

Kill switch aka transfer/bypass switch every system should have one.

 

Then the AC feed to the Inverter should have a two pole isolator

 

And the feed back back to the main db should have a 1p circuit breaker of suitable rating (to protect the cable)

 

Not sure what the cb is the right of the transfer switch, one of the above?

 

In your combiner box, there is a fuse for each string? how many strings? I can see maybe 4 fuse holders, what is between them?

 

Generally one has a 1p DC CB for each string as well in the combiner box, useful for a number of reasons.

I currently have 2 strings (left), and have space for 2 more (right). The middle thing is labeled Surge Arrest.

[kosmonooit]

I currently have 2 strings (left), and have space for 2 more (right). The middle thing is labeled Surge Arrest.

Cheers - yea I should have know, that's a code requirement and common sense. Do you have a feed to an earth spike there? Panels bonded and connected to the same? not the same as the Mains Earth

[kosmonooit]

The panels don’t always generate full power all the time. If the demand goes up, and the panels can generate more, they will.

 

But when the demand is more that the input power of the PV array?  Axpert & friends is back to Mains, unless it can dip into the batteries (SBU) but that can present  other issues

[Frosty]

Cheers - yea I should have know, that's a code requirement and common sense. Do you have a feed to an earth spike there? Panels bonded and connected to the same? not the same as the Mains Earth

Yes, I do.

[Frosty]

thanks

 

so in essence it runs off solar until to much power drawn (geyser/aircon etc) , switch back to eksdom.. and solar does nothing until load drops again. (Yes, i run our aircons and geyser of solar )

.

was wondering how they make sure there is no feedback back to grid.. most other systems have external controls talking to the different inverters (solar/battery).. its not easy to get rid of energy ..

 

(Sma uses Home Assistant and Victron uses the GX with mostly Fronius grid tie to prevent feedback.)

Reading your post again, the answer is a CT coil - this stops power going back to the grid.

 

The panels don’t always generate full power all the time. If the demand goes up, and the panels can generate more, they will.

But when the demand is more that the input power of the PV array? Axpert & friends is back to Mains, unless it can dip into the batteries (SBU) but that can present other issues

[100Tours]

Quick question on health and safety while scoping out my Grid-tied solution:

 

I am working on the assumption that my inverter and Pylontech LIFEPO4 battery be located close to each other to reduce cable lengths for low voltage cables.

 

I have a convenient location for our Inverter+Battery next to the main DB. But it is located in a general living area. Is that OK?

 

Or should I rather locate it all in the outside building. This will result in longer 220V cables to be run to the inverter and then back again to the DB, so somewhat of a cost penalty.

 

personally I would prefer to locate them outside of the living area just for convenience (neater, safer, more expansion options). Inside of your living area you are more at risk of children/pets/spills affecting your installation.

 

The longer lengths should be the 220V cables.

[kosmonooit]

Reading your post again, the answer is a CT coil - this stops power going back to the grid.

 

CT coil is just one part of the solution there, you need a controller in the Inverter that can make sense of it all and act accordingly

 

Victron has an interesting accessory in this kind of realm but takes it a bit further, its a DIN module you put in the db, connect live and neutral and it reads current, voltage, power, theta etc quite accurately  (over Modbus protocol made by an Italian company) how they use it is a configuration where you can put essential loads upstream of the Inverter  and what the Inverter will do is feed back enough power to power these loads but not send back to the grid.

 

Do I sound like a Victron saleperson? I am kinda so apologies in advance but they are great products.

 

About Vetties location, my advice would be that inside the house is not a good idea for batteries and inverter for a few reasons, locate outside in cool room with good access and cable 230V mains in and out, but please get a 1/2 decent electrician involved, even if just to advise cabling and check the work. If the work is not complaint you will loose your house insurance cover if there is a fire or accident/incident. CoC should actually be done after this kind addition or modification to the installation, but in reality anything actually goes. Safety is really the issue.

Edited February 21, 2021 by kosmonooit

[Vetplant]

Sparky just finished the wiring between the Solar Hardware (housed in an outside building) and my main DB.

 

- Oven + Geyser remains on Eskom Power. Everything else runs off the 5kW Inverter

- Change-over switch installed to be able to supply the inverter with power from Generator, if needed during long outage and no sunlight.

- Bypass switch installed to be able to supply house directly with Grid power in-case the Inverter setup fails for some reason.

 

Chuffed as chips to be this far already.

 

Tomorrow my panels get delivered and all that remains is to mount them on the rails and plug them in.

Edited March 17, 2021 by Vetplant

[Karman de Lange]

So after living with stupid load shedding early morning again while fast asleep ...

 

Try and get your house main load on a very low amp circuit breaker (below inverter rating) and put your critical things(servers/pc's etc) on another circuit so that when you overload inverter hopefully the trip will go and keep critical things on.

 

 

Its rather irritating when you forgot you load shedding and you put all appliances on in kitchen and everything trips and, then inverter restarts itself, trips again ,and repeat until you remember to switch off everything.  not so good for pc's etc.

 

Maybe a n/c contactor on high load circuit that your inverter will open on overload is better idea, jsut not sure all inverters have outputs for this.

[Karman de Lange]

Sparky just finished the wiring between the Solar Hardware (housed in an outside building) and my main DB.

 

- Oven + Geyser remains on Eskom Power. Everything else runs off the 5kW Inverter

- Change-over switch installed to be able to supply the inverter with power from Generator, if needed during long outage and no sunlight.

- Bypass switch installed to be able to supply house directly with Grid power in-case the Inverter setup fails for some reason.

 

Chuffed as chips to be this far already.

 

Tomorrow my panels get delivered and all that remains is to mount them on the rails and plug them in.

 

 

You get a ~1.5kw element for geyers , normally in the 100/50l geyers, they generic so fit into big ones.. We use it, geyser takes about 2 hrs to warm up, not 30 minutes .. so not big issue.

[The Ouzo]

Sparky just finished the wiring between the Solar Hardware (housed in an outside building) and my main DB.

 

- Oven + Geyser remains on Eskom Power. Everything else runs off the 5kW Inverter

- Change-over switch installed to be able to supply the inverter with power from Generator, if needed during long outage and no sunlight.

- Bypass switch installed to be able to supply house directly with Grid power in-case the Inverter setup fails for some reason.

 

Chuffed as chips to be this far already.

 

Tomorrow my panels get delivered and all that remains is to mount them on the rails and plug them in.

Why the heck can they not do these installations neatly. That installation would drive me insane.

[Frosty]

You get a ~1.5kw element for geyers , normally in the 100/50l geyers, they generic so fit into big ones.. We use it, geyser takes about 2 hrs to warm up, not 30 minutes .. so not big issue.

Especially on days like today (cloudy and wet).

[Karman de Lange]

Why the heck can they not do these installations neatly. That installation would drive me insane.

 

you dont' want to see mine then .. function above beauty ..