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Thank you for the great forum, Safe Driving over the weekend. Sincerely Jason


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Pietpower last won the day on August 28 2019

Pietpower had the most liked content!

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    Pretoria far east

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  1. Drove through Mamelodi again last weekend. The 230V naked cables above ground looks like a high tension distribution network with upright poles and lines spaced apart. Unbelievable that not more people/kids die from this.
  2. I only had one instance where a gas heater (boiler in this case) was cheaper to run than electrical. It was because the client had a bulk supply natural gas line with a hugely discounted rate due to high usage. Was actually cheaper than running cost of a heat pump system. If you have natural gas pipe to your house then it will probably be cheaper than electrical geyser (doubt it will beat a heat pump) but I have not had one example of LPG being cheaper. Only advantage imho is to be off electrical grid.
  3. Q=mcdT No way around it. By lowering the hot water temperature you are lowering the dT but making m higer and using the same Q(energy) Or said another way: Setting your hot water to say 45C you need to heat less but you use less cold water and thus more hot water and in the end you use the same amount of energy or gas. So why do some save energy? Most gas geysers can only handle a certain flow rate. Thus setting the temperature lower you can't use more hot water and just shower with less water. The same can be achieved with a water saving shower head or just turning the water flow down in the shower. Another saving comes from the heat loss from the hot water pipes to the environment. The higher the temp in the pipes the more energy is lost to the environment. But well insulated pipes and a short run between the geyser and shower will make this negligible.
  4. 9Amp through a 16Amp rated unit is surely within limits? It is those bad connections that cause most of the problem. Yes using a proper contactor is the correct way of doing it. But then you can use the basic 10A Sonoff which is cheaper. When you connect the Pow R2 to a contactor you lose all of it's features. It can give you the kWh used by your 2kW geyser. You can set power limits to cut out earlier if you don't want to get close to the 16A limit.
  5. I wonder if it is possible to solder the wires into the connectors in some way? Maybe solder some wires to the underside of the board
  6. Like what you are saying that an off grid inverter is a UPS with solar charging and not a SSEG (it does not push power back to the grid) Supplying a Hybrid inverter with a 15A breaker should also work then. You will just have to balance the loads on grid side vs off grid that you don't try to feed more than 15A to the grid connected loads or do some form of load management. For me it would be easy. Put everything on the backup side and only the geyser and oven on the grid side but use a load control so that the geyser switch off when the oven is in use.
  7. Do I understand this correct: To circumvent (or rather comply to) the 3.5kW requirement of COCT you simply install a 15A breaker? (15A x 230V = 3.45kW) Then it is up to you to manage the 3.5kW draw from the grid. Hardware or software management however you want to do it. The 15A breaker is a fail safe from COCT view that you will not draw more than that. If this satisfies COCT it kinda makes sense to me. Adding an inverter but limiting the draw to 15A. It is like saying yes you can add another geyser to your home but as long as it is below 3.5kW if you have a 60A breaker, nevermind if it is on or off or you feed it power mostly from somewhere else.
  8. Your diagrams for easy viewing
  9. It is not just a simple diagram. You are probably relying on the the engineer to put the information together, He probably has to drive to your place. He probably won't give you a hand sketch but an AutoCAD drawing. He has a reputation and needs to ensure information is correct before he can issue it. But as said above: Do you need an engineer? Just do it yourself.
  10. That engineer has priced for everything or maybe priced himself not to get the job. Search the forum for more info Following your thread
  11. Yes. Two geysers in series with the first one on solar and the second just doing top up temperature is what I am also looking to do. Two 150 liter geysers is below R6k excluding electrical supply and installation.
  12. You get similar stuff in the local market. But your eyes are going to water when I give you a price. Last one I did was a fair bit larger but without any elements (for heat pump) and it came in at R27,000. Smaller unit I would guess about R10k-R15k
  13. My experience with battery backups for gate motors, garage doors and alarm systems are that they are never sufficient. They are often designed to just last long enough and charge slowly. This often means they drain too far and after a year or two you need to replace them. Several batteries in different systems becomes a hassle when you have call out a technician each time a battery fails. Increasing battery capacity for each might solve the problem but not keeping the light on. Adding an inverter system and centralised batteries for lights then you might as well add these battery backup systems to the new inverter system.
  14. From that site: "Only minor modifications are needed for most standard water heaters, simple wiring modifications. NO HEATING ELEMENT CHANGES NEEDED. The wiring modifications are easily reversible." Units I came across in Europe only had a single power supply to the water heater. Explanations, most likely based on USA heaters, explained that the elements are interconnected. But then again the European market also had a vast range of different water heater types. Pipe in tank systems, tank in tank systems, some connecting to the central heating system, some using gas or combined with electricity. From the quote above I presume it is easy to rewire a system to work with solar.
  15. The low charging actually seems to be working well with the overcast weather today. My batteries are set to 40% DOD to keep some reserve for loadshedding. Should be able to last me 5 hours or two load shedding periods around here. So it dipped below 40% with load shedding this morning and now the little solar I have is enough to cover the load and add some charge to the batteries with only 50W coming from the grid. Might not charge to 100% today but then it will use eskom tonight when battery power runs out and still have enough backup for loadshedding.


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