Surge

I set the shutdown, warning and restart battery levels to lower than the current SoC so it's not that either. The batteries can be 100% SoC and the inverter still won't start in islanding mode. Maybe it's a firmware bug?

The installer installed an Earth Bonding relay in the solar AC DB (where the mains/inverter transfer switch, inverter supply switch and inverter load switches are located). The inverter just sits charging the batteries until they're full but it never supplies any power until the grid comes back up. Once it's running I can switch the grid on and off as much as I like and the inverter will continue supplying the load. I only run into the issue when the inverter shuts down due to flat batteries. If feels like the inverter has some sort of logic where it's waiting for a valid grid connection before it decides to start supplying load.

I've run into the situation where my 8kW Sunsynk inverter won't supply power unless the grid is available after it has shut down and been started up again. It has an earth bonding relay and CT coil fitted to prevent feeding back into the grid. The DC light is on but the AC is off (grid is down) and the normal light remains off. Everything works perfectly when the grid fails however I've run into the situation where extended power outages have occasionally lead to the batteries running flat and the inverter shutting down entirely. It then becomes impossible to get the inverter to supply power. The inverter boots up fine and PV charges the batteries but the "normal" light does not come back on until the grid connection is restored by the municipality. It's like the inverter is waiting for a clean grid signal before it decides to start up. How can I force it to start it up in islanding mode without removing the CT coil or earth bonding relay? I cannot find (or figure out) what settings I need to change to make this happen. When the grid comes back up, I'll hear a "click" (presumably from the earth bonding relay) and the inverter normal light comes on and the inverter starts supplying power. We sometimes have extended power outages lasting days so waiting for the grid to come back while the batteries are full is extremely annoying.

I'd like to know is if it's legal to take power off the back of an internal wall socket to an external power point. With the current heat wave in Gauteng, I'm starting to seriously think about adding some aircon units and running them off my solar sysyem during the day. I'm aware of the requirement to have an external isolator within 1m or arms length of the external compressor/condensor unit but I don't know what to expect from the aircon installers (who may take short cuts) and would prefer to prep the power point myself. I'm also aware of the requirement to have a dedicated circuit if 16A or more is required but most of the modern 12000 to 18000 BTU inverter aircons pull around 6 to 8A. As long as I pick the right unit (low power requirement) and I only use one aircon per plug circuit, I don't see why I'd need to add dedicated circuits. Having a flat roof is also a hinderance to adding new circuits to the house. 😐 I'd install 2.5mm twin and earth through the wall inside a conduit, have a 90 degree junction box on the outside wall where it comes through, more conduit to a weather proof, 2 pole isolator and then leave a weather proof plug point for the installers to plug into. Would the above pass an electrical CoC?

Thanks Steve. I'm glad Sunsynk are investing R&D in their Connect system opening the way for some home automation without needing to roll one's own solution. I managed to find a bit about the Smart Switch on one of Keith's recent Youtube clips. Evidently a Wifi enabled AC smart switch will be provided for free with all new Sunsynk inverters beginning around the March 2023 timeframe. I presume existing customers will be able to purchase them separately if they already have a Sunsynk inverter or require multiple smart switches.

Based on Sunsynk's remote control/monitoring solution (Sunsynk Connect) there appears to be an option to integrate some sort of smart switch. I presume this will allow one to control a smart switch based on inverter parameters opening the way for some automation like switching off loads when battery SoC is low or switching a light on when mains fails to indicate grid down. I cannot find anything about this smart switch online. Does anyone know what hardware is used for the smart switch? It requires one to enter a serial number and key like one does when setting up a Sunsynk Gateway (Wifi dongle).

I went with 12 x JASolar 540W panels (two strings of 6) because they fit the available roof space better. I couldn't get three rows of 460W panels and two rows of larger 540W panels in landscape orientation both maximized the area covered as well as reduced the cost of the mounting kit. The string voltages are only 240V so it may not be in the max efficiency range of the Sunsynk 8KW MPPT controllers but I really don't feel that it is such a big issue. Weather plays a far bigger role than MPPT efficiency curves. Just use what fits your roof layout and stay within the electrical specs. If a manufacturer came along with a 30% efficient panel then sure, that would be a game changer but at the moment solar PV panel effiencies are so close to each other it makes little sense to pick the biggest panels one can buy simply because it sounds better.

I haven't installed solar yet but I was thinking about this whole earthing issue and it seems to be overly complex with regards to regulations. I am wondering if an isolation transformer would not be simpler option and avoid violating any regulations? In other words install a 230 to 230 VAC transformer between the supply/grid and the inverter with it's own supply DB (and RCD if required). Then permanently ground the output of the inverter to earthing spikes so that the downstream RCD in the main DB always works on the local earthing point. Then there is always an earth reference even though it is not connected to the grid earth. If one is practically off-grid and only needs say 1kVA to top up batteries on cloudy days then the "shore power" to be imported from the grid can be limited on the inverter settings. This keeps the isolation transformer small and cheap enough. It shouldn't matter if the two earths or neutrals on each side are not referenced to each other. If Eskom/Muni screws up and has a floating neutral on their side (I've seen that happen more than once) it also won't cause any issues on the inverter side because the voltages are decoupled and float relative to each other. Would something like that work and still be legal or is there specific wording which forces one to carry the grid earth into the main DB for earthing requirements?

It's not a secret. Most municipalities make a large portion of their revenue through electricity resales. From what I can find online, Eskom sells electricity to direct customers at around R1.16/kWh. The municipalities probably get it for less. The municipalities mark it up to R2.00+/kWh with their fees, tariffs, IBT scales and other NERSA approved BS. Other than some minor distribution costs it's like printing money. Check this out from the Tshwane Draft Bylaws for Embedded Generation: 6.10 Risks 6.10.1 Economic Increases in the price of electricity and the rapidly decreasing costs of EG solutions will impact negatively on municipal revenue. In future this may lead to grid defection, with serious revenue consequences. It is therefore important that the City creates an EG connection environment that is customer-friendly. And: 6.11.1 Revenue There could be a revenue dip due to the introduction of EG, in particular in the residential sector, and this should be rectified by appropriate tariffs. Tariffs need to be adapted due to EG being part of the energy mix. http://www.tshwane.gov.za/sites/business/Bylaws/Draft%20ByLaws/28.%20Proposed%20Embedded%20Generation%20Policy%20to%20support%20and%20formalise%20procedure.pdf&ved=2ahUKEwil4PudoIXtAhVipHEKHVb9CG8QFjABegQIBBAB&usg=AOvVaw1cks5-EcFHKgeY7OFNVhpD The thought process and reasons are blatantly clear.

What is the Renusol storm washer used for and where does it go? I can't find any depiction of how it's used online. Is it a fancy seal that is sandwiched between the hangar bolt and roof sheet to help prevent leaks? If so what is the purpose of the rubber seal on the hanger bolt in that case?

Excellent! It's seems to be a key feature to avoid a floating neutral when Eskom dies.

Isn't there a difference between Deye and Sunsynk when it comes to contacts for an earth-neutral bonding relay with the Sunsynk having the feature built in? I recall reading something like that somewhere.

It's not really a Victron issue. I suspect that other brands of inverters would do the same to Pylontech BMS' on initial startup. Thanks for the recommendation about Sunsynk though. They look like really good value for money. Unfortunately finding a solar installer who supplies Sunsynk seems to be a problem - they all seem to be selling Deye kits which appear to be a watered down Sunsynk (from what I've read on Power Forum).

Yes, that's exactly what I mean. The once off inverter startup current trips the BMS (something like 200A surge when switching on a Multiplus II 48/5000). So the "normal" solution is to build a pre-charge circuit? I've just never seen this mentioned in any kits being sold. Thanks for the good idea. Seems like a very affordable way to solve the issue.

At some point in the near future I'd like to set up a hybrid grid connected system with minimal battery backup. I want to use minimal battery for purely backup/UPS to keep the costs down but what concerns me is that it seems that some hybrid inverters like Victron have a very high start up current which trips the BMS overcurrent protection on Pylontech's (and probably other lithium packs too). The Victron forums are scattered with comments like one needs a minimum of 3 x Pylontech US3000 batteries for a Multiplus II 48/5000 system in order to not trip the BMS overcurrent protection mechanism. That prevents the idea of having minimal battery capacity for lighting, TV, alarm, etc. and makes the system very expensive. Victron even have a page describing the requirements. https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom The Multiplus II 48/3000 is too small for my needs so downsizing to a smaller inverter in order to have less batteries is not an option. It seems to be a rather silly restriction in my opinion. Why can't Victron build in a "slow-start" mechanism to limit the start up current of their inverters? As this is only a startup issue it seems that if one can pre-charge the capacitors in the Victron before switching it on it would solve the problem. In fact I just stumbled upon such setups. https://community.victronenergy.com/questions/38299/phoenix-inverter-2.html What I'm curious about is why I don't see this issue mentioned in most of the DIY builds or even the kits being sold locally. How do other people get around it? Do other hybrid inverters have the same issues or does everyone build their own pre-charge circuits? I must be missing something.