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PierreJ last won the day on January 14

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  1. Yes, that would be a "Passive standby UPS utilised as off-grid hybrid SSEG". This makes the wiring less of a chore since you don't have to split out a new DB for your essential loads, but it does leave your heavy loads (e.g. oven and geyser) on the output of the inverter. Consequently you may need to shell out for two or more units in parallel.
  2. There's plenty of confusion around this topic, and perhaps at some stage even in the ranks of CoCT. However, if you look at the CoCT SSEG webpage you will note that there's only two models: Grid-tied and off-grid. "Grid-tied" is a standard term used to indicate that the inverter synchronises with the utility grid and is capable of injecting power back onto it. Everything else is off-grid. If you look at the declaration form for off-grid systems you will note that there are several options listed: • Passive standby UPS utilised as off-grid hybrid SSEG • SSEG alternative supply in terms of SANS 10142-1: 2017 - The wiring of premises • Electrically separated off-grid SSEG installations that is not interlocked with the utility electricity grid as a switched alternative Note that only the last option is "electrically separated".
  3. Axpert inverters are not grid-tied, so the approved inverter list does not apply. Your install is classified as a "Passive standby UPS utilised as off-grid hybrid SSEG". You don't need an engineer to sign off on the system, but you will need an electrical CoC, and if there is a changeover switch then you'll need to attach a test report for that. The form you need to fill out and the related info is available here: https://www.capetown.gov.za/City-Connect/Apply/Municipal-services/Electricity/apply-for-authorisation-to-install-a-small-scale-embedded-generation-system You are allowed a maximum battery charging current equal to 25% of your main breaker (i.e. 15A AC), but I don't believe a breaker is required for that if you can limit it in software. Because your solar is "off-grid" it doesn't really matter how many panels you have.
  4. I bought 5 US2000B batteries in March of last year. Two of them have since failed and were swapped out under warranty. The service from Pylontech was excellent, and the swapout process was painless in both instances. However, it is a bit concerning when you have a 40% failure rate within one year. I am hoping this was just a bad batch, and my experience is not indicative of the reliability one can expect from Pylontech batteries in general.
  5. Panels in different orientations in parallel is not a problem. If they were in series then that would have been a mistake. See the attached case study for an explanation. east-west-solar-paper.pdf
  6. 1) Disconnect the controller from the isolator and connect it to the inverter output instead (via a breaker in the essential loads DB and a new additional isolator next to the controller). 2) Connect the geyser output of the controller to a relay that you use to switch the live coming from the grid isolator. 3) Connect the switched live coming from the relay and the neutral coming from the grid isolator to the element.
  7. I see the H1 (geyser) relay has a 10A current limit, so I reckon you'll probably find there's already an external relay for the element that you can reuse.
  8. I would move everything except the element to the essential loads output of the inverter - the element remains connected directly to the live and neutral from the grid. The geyser output of the controller I would connect to a 230V relay (or contactor) that switches the live wire going to the element. Make sure that the contactor or relay you use is sized appropriately. I would go for overkill, in case someone installs a higher powered element in future. I would also size the breaker from the essential loads DB to be just large enough to carry the controller and pump - in case some fool connects it directly to the geyser element (or worse, the grid) somewhere down the line. I'm paranoid, so I might even consider putting small fuses in the control wires going to the relay if I feel there is any chance that someone may confuse those wires with the wires coming from the grid and the wires going to the geyser. Note that this is not my area, so there may be regulatory requirements that I am not aware of.
  9. Apparently there's another new model coming, the UP5000, which has a 4.8kWh capacity. It sounds like it will be even better bang for the buck than the US3000C. Link: https://segensolar.co.za/product/pylontech/storage-systems-pylontech/li-ion-battery-pack-storage-systems-pylontech/pylon-up5000-4-8kwh-li-ion-solar-battery-48v/
  10. Yes, they will work. The US3000 series is the larger capacity version of the US2000: 50% larger storage capacity, as well as 50% greater maximum charge and discharge currents. They are otherwise the same, and you can even parallel the two different models together in the same battery stack if you want to. Pylontech compatibility info is here: https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom Specifically note that you will need a GX Device (like a Cerbo) to be able to talk to the battery BMS, otherwise the battery will shut itself down after a while. Be aware that the CAN-bus pinout for the C-series batteries differs from the pinout of the B-series. You can make the cable up yourself using Cat5 cable and RJ45 jacks. The pinout is here: https://www.victronenergy.com/live/battery_compatibility:can-bus_bms-cable
  11. That'll depend entirely on the hardware. Instead of guessing - why don't you ask the client to measure all their loads with a plug-in power meter so you know exactly what you're dealing with? If I was the client I would get the 5kVA Multi with a 4+ battery cabinet, but only two batteries initially. If I run into issues with the two batteries I would just add more. In case you haven't noticed, Pylontech has released a new model: The US2000C. The price seems to be about the same as the US2000B, but it allows a 95% DoD. The US3000C is the larger capacity model.
  12. Let's do the worst case scenario math: Assuming a power factor of 0.5 for the LEDs (a capacitive load), it's 40VA per LED. If every computer has a screen, let's go for 200VA each. I have no idea how much power a CCTV system uses but it'll probably not be more than 100VA. That gives a total of 14 * 40 + 8 * 200 + 100 = 2260VA. The 3kVA Multi can sustain 2.4kW, so it will be able to carry the load. If you allow a 90% DoD on the US2000 batteries it'll give you just under two hours of runtime (when new). Given that the above estimates are on the pessimistic side I reckon it'll probably work, but there's very little room for future expansion. What if someone unexpectedly wants to run a laser printer or some other device that draws a couple of hundred watts?
  13. Yes. According to Victron, you need a minimum of 4 x Pylontech batteries with a Multiplus II 5kVA. It's not only about the total energy storage, but also the startup currents of the inverter, peak currents, etc. See here: https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom If you sacrifice the A/Cs then the energy storage capacity of two batteries should be sufficient to power your loads through loadshedding, however your battery bank would still be under-specced for the inverter. I have never tried to run my Multi with only two batteries, so I can't definitively tell you what issues (if any) you'll encounter. You could always start with two, and if you get DC ripple, BMS or other warnings then add more.
  14. Thanks! The big issue I had when I designed my system is that I absolutely wanted more than 3.5kWp on the roof, yet had to stay under the City of Cape Town's 15A current limit. The Victron Multiplus is one of very few grid-tied inverters that allows you to limit the current flow between it and the grid connection, without crippling its output at the same time. Victron also has a good reputation for reliability, and if you add a GX Device it is exceptionally feature rich. As a DIYer my installation experience was very pleasant, and everything just worked out of the box. If you do hit a snag (one of my Pylontech batteries developed an issue some time after install), Victron tech support is top notch. The Victron system is very modular, which is mostly a plus, but if you add up the cost of all the components it can be quite expensive. Although the sticker on the Multiplus II says 5kVA, it is really a 4kW inverter if you look at the spec sheet. Those are the two negatives for me, but overall I am very happy with my purchase. I don't know much about the SunSynk other than what I've read on these forums. It certainly looks like great bang for the buck, but I don't think there's enough evidence yet to draw a conclusion on reliability.
  15. Hi Hennie, I've currently got 16mm^2 cable and a 63A breaker between the combiner and MPPT. I have five strings so the maximum rated current is 5 x 11A = 55A. So far (touch wood) it hasn't tripped. The MPPT is rated at 70A input current, and given that I have space for another string on the roof, I was considering adding a 6th string... now I'm not sure that is a good idea anymore. Thanks for the warning.
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