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HennieW

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  1. Hi PierreJ One thing you need to take cognizance of is during autumn and spring when it is cold, with occasional clouds, with bright sunshine hitting the cold PV panels when the clouds part, you get a huge spike in the current delivered to the MPPT controller(s). I have had more than doubble the rated PV current delivered for a couple of seconds during these times. The point is your cables from the combiner box to the MPPT controller need to handle this spike. I have had my combiner box main 50A trip during such conditions. Just a heads up. Nice installation.
  2. HI Piet You are correct in what you are posting. The Inverter must conform to the SANS code for a UPS system. Look up the SANS code for inverters and your electrician must also sign it off as such. Then also the UPS maximum charging current from the municipal grid (draw and push through to the load) must be limited to 25% of the main breaker (60A) size. It must be a hard limit. i.e Breaker of size 15A. is preferable. The software limit can be easily changed and is not recommended. However during sunny, sunshine days you may push to the load as much as needed from the sun and battery, but not draw from the grid more than 15A. Usually the load is drawn from the sun and batteries at the same time or from the battery only or from the sun only. It is the SBU setting (Solar battery and then utility), but in utility mode up to max 15A. I feel very sorry for the municipal guys that need to manage their grid as the grid was not designed for load shedding. Full stop. Look closely at this photo of the supply voltage quality the first couple of minutes after load shedding. It is terrible and will cause failure. That is why I recommend you place all your sensitive equipment on the UPS. The 25% load limit is placed there because the grid cannot handle more than that AT THE SAME TIME. After load shedding this is what happens to the grid voltage. You are warned.
  3. HI All As a user for some time now I share my experience on the 15Amp limit and how to manage it. I have two Axperts (2x5kVA), 6000W PV and 12kWh storage. It is deemed as a UPS with solar charging. Not a SSEG connected to the grid. I post these four diagrams for use to users that want to install more than 3500 watt of solar panels and have battery storage. In my case I utilize shore power (municipal power) for between 3.6% and 12% of the time per month over a 12 month period. There are many days (even weeks) when I do not connect back to shore power at all, but I need shore power when cloudy days persist for many days at a time and battery drops to below +-20%. August is the worst. Connecting back to shore power usually happens between the hours of midnight and say 09h00 at the latest the following day. In August it is longer, but it is only for that month.Solar block diagram 1-4.pdfThe purpose of my system is to be independent of municipal power as far as possible, and If the basic service fee increases to such an extent, then I will go completely off grid and operate a remote start generator for the 3,6% to 12% of the time. In diagram 4 you have the best of both worlds. A Bypass switch, is very useful when things go wrong, but so is a suitable change over contactor that is operated by the software on the inverter. Diag 1 and 3 are similar but in diag 3 the bypass can handle more than the 15A as is currently allowed. In any case manage your loads via software or timers. Use the washing machine, tumble dryer and dishwasher when the sun shines. Any comments or questions will be welcome.Solar block diagram 1-4.pdf
  4. Hi All I have found this product to be relatively cheap and reliable for a 2 to 3 hour outage. It takes care of the power requirements of the entertainment center and some portable lights. Fridge can stay off for the two to three hours. Would like to heat from other members what low cost solution they have for the power outages
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