Posted March 10, 20232 yr On one end you get a pure grid tie inverter, no batteries, and when the grid goes down so do they. Straightforward Where then do these hybrids like? For example the Luxpower SNA, it can blend AC, solar and battery. You can turn the blending off though. If you blend is it a grid tie, or can an offgrid inverter blend? Also what makes an offgrid inverter like an Axpert not be considered a grid tie if it supports AC in. Is it the lack of blending? In other words what makes an inverter a grid tie versus an offgrid inverter that supports AC as an input? The classification matters for municipality registrations etc. Edited March 10, 20232 yr by Lee2
March 10, 20232 yr My understanding is if it can or does feed back to the UTILTY past your meter then it is a grid-tied inverter. Off-grid like the axpert you mention cannot technically feed back to the utility grid so not considered a grid-tied inverter. It is essentially just a clever UPS plugged in to your ac supply.
March 10, 20232 yr 1 minute ago, Lee2 said: What is a Sunsynk? grid-tie as it can push power back to the utility if setup that way. I do not know the other Luxpower so cannot comment on that one.
March 10, 20232 yr LuxPower SNA 5000 is an off-grid inverter according to all descriptions online. Looks like an expert type clone. Edited March 10, 20232 yr by WannabeSolarSparky
March 10, 20232 yr Author It allows feeding in to the grid according to the manual https://www.solar-europe.co.za/wp-content/uploads/2021/09/Lux-Power-5KW-Off-Grid-SNA5000WPV-User-Manual.pdf
March 10, 20232 yr 4 minutes ago, Lee2 said: It allows feeding in to the grid according to the manual https://www.solar-europe.co.za/wp-content/uploads/2021/09/Lux-Power-5KW-Off-Grid-SNA5000WPV-User-Manual.pdf That most likely referring to the local grid. Have you checked the spec sheet for that inverter? It should say on the spec sheet if it has anti-islanding protection, if it does then it will be a real grid-tie inverter else it will be an off-grid inverter as the above doc seems to indicate. I think on that doc they referring to the software to manage the inverter and seems to suggest they saying the feed to grid must be set to off for this inverter. I may be wrong, but the spec sheet will give a better answer
March 10, 20232 yr the LXP is a grid tie inverter as per the spec sheets https://www.solar-europe.co.za/product/lux-power-inverter-5kw-hybrid-lv-single-phase-lxp5k/ This one you are referring to is NOT a grid-tie. https://www.solar-europe.co.za/product/lux-power-inverter-5kw-off-grid-lux-sna5000wpv/
March 10, 20232 yr In my understanding: Grid Tie is an inverter that has no battery connection. It has an MPPT controller & inverter that converts Solar PV DC directly to 230V AC to feed your home and excess goes to grid. For safety reasons, it is required that the inverter stop feed back/switch off when grid is down. These are often called Micro Inverters and can be installed under the PV panels. Due to load shedding, these are not common is South Africa. These can be combined with a something like Tesla Powerwall to operate like a Hybrid Inverter. Off-Grid inverter is a "UPS", has batteries and does can not feed back to the grid. The load is connected on the "UPS/Essential Side", the grid side is never reverse fed. It may have MPPT controllers and use Solar PV or Grid to charge the batteries. Hybrid Inverter is a combination of the two and typically has MPPT (DC), battery (DC), UPS/Essential Load side and Grid Side. You can grid feed or feed just enough to power appliances on the grid side (zero export). Some off-grid & hybrid inverters only don't have MPPT controllers and rely on external MPPT controllers. >In other words what makes an inverter a grid tie versus an offgrid inverter that supports AC as an input? If the inverter can feed back to the grid, it is grid tied (hybrid is also grid tie capable). >The classification matters for municipality registrations etc. Always use inverters that are on the NRS 097-2-1 list. https://resource.capetown.gov.za/documentcentre/Documents/Forms, notices, tariffs and lists/Approved Photovoltaic (PV) Inverter List.pdf >If you blend is it a grid tie, or can an offgrid inverter blend? No "blending" does not make it grid tie. Some Hybrid & Off-Grid inverters will allow a pass through of grid to the UPS side support higher loads. Some inverters will "blend" Solar + Batttery + Grid to support the UPS load. What do you mean by Blend? Blending Solar DC with battery DC with grid AC on the load side is not grid tied. Feeding or having the ability to feed the grid is "grid tied". Grid tie also includes inverters configured to support loads on the grid side are fully/partially powered by the inverter (zero export). Here is an example of an 8kW inverter "blending" the load side. The load is 10kW and it's "blending" 5kW from Sun, 3.5kW from battery, 2kW from grid Numbers don't quite add up due to refresh delays. Edited March 10, 20232 yr by system32
March 10, 20232 yr The definitions here are as I understand it. COCT famously have a list. I think that's the only way this sort of regulation can be done. I would bet that my Goodwe is not listed as "grid-tied". It could be installed with just PV and no batteries, and work like a grid-tied system, but batteries can be added and settings changed, so I'd be surprised if they let me get away with calling it "grid-tied". Grid-tied are actually what utilities want to encourage, because you are more likely to have excess power available for export. Once you have batteries you want to make sure they are getting charged, and not from grid unless it's absolutely necessary. I think you do get them in SA, but they're not first choice for domestic applications. Last month I went to the dentist. She is at a medicross practice. They have lots of panels on the roof. Load shedding starts whilst she's drilling, The lights and all the equipment go down. She lifts her hands and I hear her say "1... 2.... 3.... WHAT? Where's the generator?" Then the generator kicked in and she carried on working again. Grid-tied solutions make a lot of sense for shopping malls, medical out patient facilities, any sort of enterprise that does the bulk of it's business during the day. The system will save you money, and you would need a big battery bank for such a building, and lots of wiring.
March 10, 20232 yr 2 hours ago, Lee2 said: You can turn the blending off though. If you blend is it a grid tie, or can an offgrid inverter blend? Also what makes an offgrid inverter like an Axpert not be considered a gri The modern Axpert Inverters , from MKS3 upwards and MAX 7.2 upwards can blend because it is grid-tied. BUT it is configured not to export any power on the Grid connection. In other words it will only supply enough pv to blend the load demand, and will not supply any additional pv power onto the grid. This is in contrast with a sunsunk which can be configured to do so via current sensing (ct) measurements on the grid side. The Axpert blends pv and battery DC sources on DC coupling level. It blends grid input with the inverter output by synchronising to the grid and then AC coupling the grid with the inverter output by connecting the two AC sources together. This is by definition pure gridtieing. Edited March 10, 20232 yr by BritishRacingGreen
March 10, 20232 yr 2 hours ago, BritishRacingGreen said: The modern Axpert Inverters , from MKS3 upwards and MAX 7.2 upwards can blend because it is grid-tied. BUT it is configured not to export any power on the Grid connection. In other words it will only supply enough pv to blend the load demand, and will not supply any additional pv power onto the grid. This is in contrast with a sunsunk which can be configured to do so via current sensing (ct) measurements on the grid side. The Axpert blends pv and battery DC sources on DC coupling level. It blends grid input with the inverter output by synchronising to the grid and then AC coupling the grid with the inverter output by connecting the two AC sources together. This is by definition pure gridtieing. Was grid tied not a term developed for bi-directional inverters? I do see see lots of talk when an inverter is grid connected that people think it is grid tied. For me it is not the same. The same could be said of the term hybrid vs pure hybrid. It seems that a more than 1 function inverter is also called a hybrid by sales staff. Even in EVs hybrids could not be charged accept while driving and now some also have a charging socket. Edited March 10, 20232 yr by Scorp007
March 10, 20232 yr 54 minutes ago, Scorp007 said: Was grid tied not a term developed for bi-directional inverters? Yes, in fact the functionality of gridtie in hybrid mode (see my post below) dictates a bidirectional inverter, because there is only one connection (grid and inverter output tied together) .so this bidirectional path must both facilitate grid battrry charge in one direction, and battery/pv discharge in other direction. The newer axpert are fully bidirectional, there is no notion any more of a seperate grid charger controller on the main board. Edited March 10, 20232 yr by BritishRacingGreen
March 10, 20232 yr 21 minutes ago, Scorp007 said: The same could be said of the term hybrid vs pure hybrid. It seems that a more than 1 function inverter is also called a hybrid by sales staff. While I by no means are long enough in this business to give definitive answer, my understanding is that it comes from the microgrid background, where a pv inverter is a typically a single ac coupled inverter, eg Fronius, and a battery inverter is typically also a single ac coupled inverter. In modern times these 2 functionS are also combined for simplicity and cost, eg. SUNSYNK, hence the term hybrid. Edited March 10, 20232 yr by BritishRacingGreen
March 10, 20232 yr 18 minutes ago, BritishRacingGreen said: While I by no means are long enough in this business to give definitive answer, my understanding is that it comes from the microgrid background, where a pv inverter is a typically a single ac coupled inverter, eg Fronius, and a battery inverter is typically also a single ac coupled inverter. In modern times these 2 functionS are also combined for simplicity and cost, eg. SUNSYNK, hence the term hybrid. Same understanding here, notwithstanding the reality that battery inverters with a solar input have similarly come to be called hybrids.
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