pilotfish

I have 20 x 310Wp in 2s10p arrangement, with the +ve of each string fused with 12amp fuses in the combiner box. Some time after installation I noticed a drop in production, after investigating I found a blown fuse which turned out to a 10amp that had been mixed in with the 12amp fuses supplied. I believe that 10amp is too low when using panels 300W and above.

Just a question... Does CoCT not have the same rules as JHB where a grid feedback user must be a net consumer? In other words they will never pay you or credit your account, any feed back in excess of consumption is a donation (but you must still pay your TOU connection fee of R530).

Eskom quotes individual (exorbitant) rates based on the actual work required, whereas City Power for example would quote off a menu - so there is no way to estimate the Eskom upgrade cost.

I have always help the same opinion as him - the confusion was brought about by CoCT which stated that (in my own words) any inverter that has a grid input is a Grid Tied inverter in their opinion, irrespective of its ability to feed back into the grid. The reason that I intend to eventually get around to installing the change over is that I don't even want to get into the argument, if and when they knock on my door I just want to be able to say "I am off-grid, please pi$$ off".

Sure, I have 20 x 310W panels

Nope. R=V/I, quite a big difference in your result!

State of charge. Summer/Winter = 90c/95c, the times and tariffs are in the 2 PDF's in my comment near the top.

Note that this comment applies to domestic systems. If you are a business with high daytime consumption and low after hours consumption then that is a different story.

I have not looked into Ekurhuleni regs, this applies to City Power only.

...and no AC feed to your inverter. The inverter system must be PV only, when batteries go low then the C/O switches the PV-DB to grid, and then back to PV when batteries have reached preset SOC.

Yes, you will go from prepaid at R0.00 connection fee and R1.50/kWh (as long as you design your system to remain below tier 1 of 500kWh/month) - To Time of Use at min R550/m connection fee and R3.30/kWh when you get home from work and need power (6pm to 10pm and 6am to 10am). Note that the above numbers are from memory so don't nit-pick if out by a few pennies/minutes Yes, but when I asked about a TOU meter about 18 months ago when considering a smaller system with grid charge in the middle of the night at very low rates, I was told that they were not available, despite being available in their tariff pamphlet -eishh! So I went the prepaid route and damned glad that I did now.

I am not going to get involved in this discussion other than to offer this one opinion (because the conversation is an endless circle); There is no value in installing a grid connected system in JHB (which includes any inverter that connects to the grid, irrespective of its ability to feed back into the grid). The authorities have carefully calculated costs and complexities to make it just a dumb thing to do. In my opinion this is intentional to protect their revenue stream of which electricity sales is the major contributor. If you want to move forward with solar then make sure you are "Off Grid" in that your inverter and the grid never meet. This can be accomplished by Having a Grid DB for things like Oven (gas?), geyser (solar?), A/C, under floor heating etc. Then have a PV-DB for lights, general plugs (not space heaters), fridge, TV+Decoder, PC's, internet, etc. You can have Grid Backup for the PV-DB via a suitable separate changeover switch. This solution (off grid) will require that you register with Nersa as an SSEG when the time comes and regs are settled (unless panel capacity is below a pathetic 250W apparently), and have a COC for the installation - but no special applications, approvals, engineers, tariff changes etc etc etc If you look at the numbers and feel that there is value in going the Grid Connected route then go for it.

All grid-tied installations, irrespective of the size, have to follow the process outlined by City Power for the Johannesburg metropolitan. PV system installation in Johannesburg All City of Johannesburg customers planning for PV system installation should follow the permit application process prior to installation and commissioning of the PV system. It is mandatory for customers with PV systems already installed to follow the same process and register/regularize their installations with the system and connection requirements of City Power. We advise that all our installers familiarize themselves with the permit application process and hope that the following few point can assist in ensuring responsible supply of world class tier 1 PV equipment. Applicable standards and guidelines The technical requirements for Small Scale Embedded Generation are covered in the following standards and guidelines. All installers preparing for an application should ensure compliance with the SSEG standards and guideline indicated below, among other recognized standards: 1. City of Johannesburg By Laws for Electrical Connections 2. SANS 10142 3. SANS 959 4. South African Renewable Power Plant Grid Code. 5. NRS 097-2-1 Grid interconnection Generation (Utility interface) 6. NRS 097-2-3 Grid connection of Embedded Generation (Simplified utility connection criteria for low-voltage connected generators). 7. IEC 62116 Test procedure of islanding prevention measures for utility-interconnected photovoltaic inverters. 8. IEC 62109-2 Safety of power converters for use in PV power systems – Part 1: General requirements. 9. IEC 62053-22 Electricity Metering Equipment 10. IEC 60364 – 1 Low Voltage Electricity Installation A site survey is very important as many installations are done at sites were pre-paid meters are currently installed. No system will be allowed to be connected to a pre-paid meter even if the system will have zero exporting. The only meter that is currently re-programmable for bi-directional application is Itron. All other meters will need to be replaced. Provided all embedded generated power is legally connected by following the permit application, City Power welcomes grid feeding of all Renewable energy sources. Acceptance of the plant Once all commissioning tests have been completed and the installer has issued the relevant COC for the installation, it will be the responsibility of the Installer to notify City Power of the status and request an official commissioning date. City Power will provide a date for their Engineer to visit the site together with the registered PR engineer and the commissioning documents will be signed off simultaneously by both parties at the site. Embedded Generation Tariff.pdf COJ Tariff - TOU.pdf

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The committees that make these decisions are loaded with people representing special interests, Voltronic is unlikely to be represented and thus has zero chance of ever making it onto the approved list.

Interesting, in JHB you may NOT be on prepaid, but must be on Time of Use (TOU), this will currently cost you about R525/m before you use any power (see attached rules and tariff docs). Then if you put on a load like heating between 7am-10am and 6pm-10pm you will pay an eyeball melting R3.30/kWh. Each person would be affected differently but I guess my monthly cost will rocket from around R250/m (summer low around R100 and winter high around R750) to average around R1000 (extra R500 for connection fee and double my current average consumption cost). This after jumping through all the grid-tie compliance hoops, which will cost a bundle - the following from the web; >> All grid-tied installations, irrespective of the size, have to follow the process outlined by City Power for the Johannesburg metropolitan. PV system installation in Johannesburg All City of Johannesburg customers planning for PV system installation should follow the permit application process prior to installation and commissioning of the PV system. It is mandatory for customers with PV systems already installed to follow the same process and register/regularize their installations with the system and connection requirements of City Power. We advise that all our installers familiarize themselves with the permit application process and hope that the following few point can assist in ensuring responsible supply of world class tier 1 PV equipment. Applicable standards and guidelines The technical requirements for Small Scale Embedded Generation are covered in the following standards and guidelines. All installers preparing for an application should ensure compliance with the SSEG standards and guideline indicated below, among other recognized standards: 1. City of Johannesburg By Laws for Electrical Connections 2. SANS 10142 3. SANS 959 4. South African Renewable Power Plant Grid Code. 5. NRS 097-2-1 Grid interconnection Generation (Utility interface) 6. NRS 097-2-3 Grid connection of Embedded Generation (Simplified utility connection criteria for low-voltage connected generators). 7. IEC 62116 Test procedure of islanding prevention measures for utility-interconnected photovoltaic inverters. 8. IEC 62109-2 Safety of power converters for use in PV power systems – Part 1: General requirements. 9. IEC 62053-22 Electricity Metering Equipment 10. IEC 60364 – 1 Low Voltage Electricity Installation A site survey is very important as many installations are done at sites were pre-paid meters are currently installed. No system will be allowed to be connected to a pre-paid meter even if the system will have zero exporting. The only meter that is currently re-programmable for bi-directional application is Itron. All other meters will need to be replaced. Provided all embedded generated power is legally connected by following the permit application, City Power welcomes grid feeding of all Renewable energy sources. Acceptance of the plant Once all commissioning tests have been completed and the installer has issued the relevant COC for the installation, it will be the responsibility of the Installer to notify City Power of the status and request an official commissioning date. City Power will provide a date for their Engineer to visit the site together with the registered PR engineer and the commissioning documents will be signed off simultaneously by both parties at the site. (Note - it took 8months to arrange a prepaid meter after paying for it, this will likely to take a year or more and cost thousands. If not approved then start again!) << Eishhh.... Domestic PV in JHB is almost impossible to justify if you go the grid-tie route. Embedded Generation Tariff.pdf COJ Tariff - TOU.pdf

There is no rocket science to what I am planning, I intend using a contactor with 2x n/o and 2x n/c contacts to perform the changeover role currently performed by the Axpert, thereby allowing my system to be classified as off-grid instead of the bogus grid-tied classification they currently choose to apply. With the above arrangement there will be no point where the Axpert setup comes into contact with the grid. I understand that I may have to register as an SSEG (eventually), but as an off-grid setup there will be no dealing with ineffective council, no tariff changes and no engineer sign-off, I will do my own COC. I dont want to go the route suggested by TTT because I am currently on prepaid and average about R250/m over the year at a low unit cost because of my low usage - the moment I am classed as grid-tied I will attract a high monthly connection fee, higher unit costs, and jump through various impossibly tight hoops - no thanks, I HATE red tape! The perceived downside is that I wont have grid charge available, but I charge solar only so if the C/O is successful it will have zero effect on my current situation which is very effective. The only "development" that I need to do is to try and get a changeover setup that will allow the operation without affecting PC's/TV;s/Decoder/Amps etc - failing which I will need to install UPS's which I am trying to avoid. I was hoping to do some experimentation this weekend but life intervened.

My understanding is that is that your system as described above would be classified as off-grid, meaning that in order to be fully compliant you have to; Register only (existing tariff remains), No engineer sign-off required, Get a COC for the PV system (independent source of power exceeding 50V), Normal SANS regs apply to balance of installation. I would suggest using your normal Bulk/Float voltages for charging via the Axpert on daily basis, install HA-02's for daily balancing (one set of terminals per battery). Once a month on a good sunny day you manually switch C/O to grid, set float=bulk (57.4V or whatever you use), and blast a good charge into your bank at high voltage for the full day - set back to normal at sunset.

...and pondering further... I like to control my switching based on SOC info provided by the BMV. If I use the Axpert output directly to control the coil then when the Axpert shuts down there will be a moment when there is is no power on the contactor output before the coil releases - I am trying to minimize this changeover time to hopefully achieve a delay short enough to not affect PC's etc. If I control the coil via Axpert output through the BMV contact then there will still be power on both inverter and grid inputs when the coil release instruction is sent by the BMV - the C/O time then is minimized (whether or not this is fast enough is yet to be established). It will have the additional function of C/O in the event of Axpert output failing for any other reason.

Yes, I didn't consider doing it directly from inverter output, but now that I think of it it is the natural and simple solution.

You should consider adding a strippers pole

You can use any size wire for plugs, so long as your CB is rated for the smallest cable in the circuit. Use 1.5mm wire for plugs is CoC compliant, so long as the CB is 16A or lower 2.5mm for geyser on a 20A CB is fine, but on a geyser your earth wire should be min 2.5mm so you cant supply with Surfix/FTE because the earth wire is not 2.5mm (you can use if you run a separate 2.5mm earth.) @plonkster I hope that the 25a CB is not directly supplying any plugs or switches that are rated at 16amp without sub CB's because your CB may not exceed the rating of you socket/switch by more than 25% - so max 20amp CB no matter what size cable you use.

I have just purchased similar equipment and will be testing over the next few days, hopefully I will have a working prototype after the weekend. Single changeover contactor, 220v coil powered by inverter I would prefer a 48v DC coil powered by battery bank but this wasn't available for at time of purchase Controlled by BMV or Axpert dry contact or both Simple and relatively cheap.

It will half work... It will pass power if correctly orientated and block power if not.

Exodus used to be great, but then fell away to be surpassed bi Incursion (in my opinion), but it got too frustrating to use as the servers are overloaded and you can start watching something only to have it fail half way through.