Stanley

There are basically 3 types of inverter, although in those broad 'types' there could be many different brands and models with slightly different functionality. You get the PV grid-tied inverters which basically connect solar panels to the grid. i.e. They feed any available solar power into the AC grid and they don't have a battery connection, which means they rely on the presence of the grid to operate so if the grid goes down (load shedding etc.) they stop working. Then you get hybrid inverters which work in a similar way to PV grid-tied inverters, in that the inverter operates in

I agree, all installations should pretty much look the same whether you are using category B or C. If you have a look at this example circuit diagram that MLT Inverters supplies for a typical Oasis installation, the same external hardware such as the changeover switch (called a bypass switch in the drawing), circuit breaker, fuse etc. are all pretty standard for any type of installation. The added benefit of the external changeover switch is that it can appear (to most electricians and even the CoCT SSEG department) to fulfill the requirements of the changeover switch mentioned in the SSEG doc

This is what I understand about the CoCT Passive standby UPS requirements: A Passive standby UPS is one in which the inverter doesn't run (i.e. produce it's own AC output) while the grid is present. In other words, the loads are switched to the grid through some sort of changeover switch, which could be the internal passthrough and the inverter is basically off. The UPS is allowed to charge the battery during this time subject to the AC current limit of 25% of your main breaker size. The switch that disconnects the load from the grid (internal or external) must comply with SANS 60947-6-1.

This is grid-tied hybrid, which is not quite the same as regular grid-tied PV inverters. A hybrid inverter typically takes PV and a Battery and can therefore supply the essential loads when the grid has failed. So in the case of a grid-tied hybrid inverter (hybrid inverter that runs in parallel with the grid) the internal changeover switch that disconnects from the grid when the inverter runs off-grid must comply with SANS 60947-6-1 (You will notice that Standby SSEG has the same requirement, so basically any time essential loads can be supplied by the grid and the inverter, there must be

I think this latest document from CoCT explains the Inverter size limits much more clearly than previous versions. SSEG residential generation size limitations (2020-08-14) (003) (4).pdf

There is your problem. A hair dryer is typically > 2kW, I think my wife's is rated at 2.3kW. The Microwave probably around 1kW. Assuming there is another 200 or 300W base load, this is enough to trip both the battery and the Goodwe. So the question is which one is tripping. Since you say it restarts after a few seconds, I would have to say it's the Goodwe tripping, because as far as I know if the Pylontech trips on over current, you need to manually reset it. Edit: Sorry, it's actually not enough to trip the battery since the 74A (for 2 batteries) is not a hard limit, and the

I hate being scammed from wherever the scammer is Sorry, my OCD couldn't help but notice the typo.

Another thing you can try is to open the battery and measure the pack voltage directly on the battery terminals to make sure the voltage drop isn't through the internal contactor / wiring etc. While you are at it, you should maybe measure the voltage of each cell to make sure that none of them are very high (>3.65V) or very low (<2.8V)

For batteries, I can recommend Freedom Won, Solar MD and Pylontech. Pylontech is nice because it's modular and you can easily add more later. Solar MD also allows adding more quite easily but they are wall mounted or their own proprietary rack mount form factor (so must use their rack) Freedom Won is floor standing and look quite pretty, you can also add more but only of the same capacity so if you start big you can't add just a little bit more later.

Regarding the CoCT size limits, this is the latest document which makes it much clearer.

Do the affected computers already have UPS'? I have found that often the culprit is a UPS with a dead battery. The UPS detects the glitch as the inverter transitions from on grid to off-grid and then switches to it's internal battery which, if it's dead, causes the PC to turn off. In these cases simply removing the UPS solves the problem. Flourescent tube lights will usually turn off and on again because it doesn't take much of an interruption to extinguish the arc inside the tube.

I would definitely go with Pylontech, never had a single problem with them, on the other hand I have had nothing but problems with BlueNova. Not to mention that their so-called 4kWh battery is actually 3.2kWh, but if you ask them about it they claim that they spec. the C10 rating which is ridiculous. That particular battery you are looking at, which BlueNova claim to be 77Ah has 60Ah cells inside (the capacity is printed on the cells by the manufacturer).

Oh, I forgot to mention, the Nomad has 2 MPPTs in it, which should be great if you are using 2 strings of different panels.

The MLT Inverters', Nomad charge controller has a maximum Voc of 375V https://www.mltinverters.com/documents/nomad_manual.pdf (In the manual it says the maximum input is 400V, but that just means it won't blow up at 400V. It will refuse to operate if the input is above 375V)

@plonkster, your answer has left me with a couple of questions. Does this mean that multi doesn't run in parallel with the grid if the option to export excess PV is turned off? (By this I mean it isn't inverting when grid connected, but using a PWM charge method) If this is the case, then it should be able to drop the current to 0 under all circumstances by stopping the PWM completely. I'm assuming it works the way some other inverters work in this mode by changing the switching mode so it works as a boost converter using the filter inductor as the boost inductor. If this is not