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P1000 last won the day on February 12 2020

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  1. Chopping sine waves will not work well with any inverter that I know of. I would not recommend going this route. It will work if you only use it while grid-tied, but I still don't recommend it. If you do decide to go this route - use one that uses a triac for control. If it is just a thyristor, the output will be chopped DC. Well more like chopped rectified AC. That is not a good idea for a geyser element.
  2. If they are the next best thing, you might as well buy LiFePo4 now, and by the time you have to replace them, the LTO price would have dropped so much that it works out cheaper. With batteries that have a longer life, the risk of them failing due to something else also increases a lot (longer life = more time to develop another issue). Most of the failures of LiFePo4 you hear about is not related to end-of-life, so with that in mind, I would be hesitant to spend 3x the money on something that might last longer.
  3. I think the heatbed is triac controlled - either by chopping the wave like a dimmer, or by simply switching on and off at a fixed interval (or not - like dithering with Bresenham's line algorithm). The better method to control a heater is to use Bresenham's algorithm slaved to the line frequency. That would mean that it can only turn on a complete cycle but also that it could turn on for a single cycle. All of the above methods will cause interference with inverters. If it really bothers you, the best method in my opinion would be to get a DC heat bed that runs off a SMPS at high frequency PWM.
  4. If I read that graph correctly, the 31,4A is at 48V, so it should not cause an issue. Your microwave did not consume 7222VA.
  5. I don't think there are official distributors, but I have seen individual imports before.
  6. Well, I think the advice from Coulomb is worth a lot more than my input, so you really should be thanking him
  7. Just to chime in. PWM is always inferior to MPPT, except in perhaps a very specific case, and will only be so for a small part of the year (or day). PWM has no storage component - it really is just what it says PWM. It will connect the solar panel to the battery with a mosfet until the battery voltage exceeds a setpoint and then disconnect until it goes below setpoint minus hysteresis. So it also cannot output more current than the panel current. The big loss in efficiency is the fact that you lose all the power in the voltage mismatch between panel and battery. So if you have a panel that delivers 20V and 5A (at peak power in this example case), and a 12V battery, you will only be able to deliver [email protected] to the battery, which means you lost out on 40W.
  8. All the appliances you mention work on the basis of switching an element/magnetron on or off. Lower settings simply mean that the on period will be a smaller percentage of the time. This means that the inverter should still be capable of carrying the full load.
  9. It is usually a lot cheaper to add more PV panels than erect a tracker.
  10. This should last you a while: (mine has been running flawlessly for 7 years...) https://www.sustainable.co.za/laing-ecocirc-d5-38-700b-circulation-pump.html
  11. Yes it is possible. I do not know of any like this available at the moment, though. There are a number of inverters that work like this: Battery -> boost -> HV DC bus Panels -> boost/buck-boost/etc -> HV DC bus and then from the HV DC bus -> AC 50Hz So now you just need an extra battery <-> HV DC bus for all excess loads. (The battery will be either bidir or also have a buck from HV DC -> battery, there are other simplifications as well.) Overall it adds a lot of complexity for installers and will be a nightmare dealing with complaints etc. But certainly possible technically.
  12. In this scenario, what is the definition of a "rectifier" as you have used it here?
  13. By ADuM I mean something like this: https://za.rs-online.com/web/p/digital-isolator-ics/4967519P/ For sure arresors maybe 1ohm through-hole resistors going to these: https://za.rs-online.com/web/p/tvs-diodes/0508018/ (PESD12VL2BT,215)
  14. I like the FTDI stuff. You can get them from RS, but they are a lot more expensive than others. You will probably find what you want at Micro Robotics (PL2303). On opto-isolation: That could work but it is probably not going to be that simple - you need to arrest the surge and make sure it stops before the isolation barrier (on both sides) and have a fuse of sorts and enough distance to prevent breach. I have seen a number of very well designed isolation interfaces that failed to actually stop the surge from propagating simply because it is really difficult to do well in the real world. I like the ADuM range of digital magneto-isolators for communication, but they require power on both interfaces.
  15. Not in an official manner. The fiber converter has it's 12V running over 2 pairs, data over the other 2 - so "power over cat6" perhaps. My Ratel has no PoE output either.
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