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Javi Martínez

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Javi Martínez last won the day on November 16 2019

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About Javi Martínez

  • Birthday 09/05/1975

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  1. @NickM95 Yes. If you use a 10 ohm resistor it´s right. At high levels of radiation, It will be 200 mA and V in resistor will be 2 V and this value is far from Vmp so it can be considered Isc. Then, if you have e.g., 1.5 V, you´ll have a radiation level of 750 W/m2 . What we obtain from ADC is a value "k", wich varies from 0 to 4095. 0 is 0 Volt and 4095 is 3.3 V. If we want measure volts, we only have to use this : V(volts) = k / 4095 * 3.3 In your case, once you have measured volts, yo do this : rad = 500 * V(volts) = 500 K / 4095 * 3.3 = 0.4030 * K "500" is the conversion factor from Volts to Radiation, because 2 V represents 1000 W/m2 in your case.
  2. Well, nowadays we have incorporated on-grid inverters: Huawei -> Modbus TCP Fronius-> API SMA-> Modbus TCP All cases are available to divert and avoid feed in the grid.
  3. Hey we use a free plattform called PVControl+ In this video you can see how to divert de solar production when it is possible. In this sample, we have a pair of Sunny Boy and one Sunny Islad. When energy is enouh, it is used to feed 4 heaters, you can see SSR relays moving. https://www.youtube.com/watch?v=gwMpXHW_JNg&feature=emb_title
  4. https://www.google.com/url?sa=t&source=web&rct=j&url=https://pvsec-27.com/wp-content/themes/pvsec27/abstract/pages/abst/10458.pdf&ved=2ahUKEwjqlOr__t3mAhULXRoKHTvWAZsQFjAJegQIAxAB&usg=AOvVaw312mgEpw9Sv9MVn57VEjKy
  5. It is easy to solve using 2S6P config per inverter. If pannels were 60c you could use 3s4p, but it is not this case.
  6. Did you measure active power or only current? It could be reactive power. If you can't measure active power you can do a simple test. When battery full and no loads in AC output, measure current. If you obtain 800-1000 W, it is reactive power.
  7. Yes, I agree, but the question was clear. I don´t know if @Kilowatt Power wants other kinds of advice. If I were in that situation, depending on the amount of water per day needed, I would install the next: 7-8 Kwp pannel and a 11 KW VFD. I would limit frequency to 40-42 Hz in order to reduce the power needed, being sure that the refrigeration of motor is enough. Power would be 4-5 kW and flow rate 5 m3/h. If it is neccesary, at night, I would feed AC IN in the same VFD whith a pair of Axperts in parallel and an Autotransoformer, 230-400 W 5 KVA, whith the same frequency. Also, an inductance is needed after VFD, since the line is too long. Concerning batteries, 20 kwh LiFePo4 could be enough. The autotransformer has two functions, increases voltage, and avoid spikes from VFD to inverter.
  8. I think the motor we are talking about is inside this table: As you can see start current is 123 A...¿How many Axperts do you need?
  9. If you want to get a good measure of inrush current, you can lock rotor while 2 or 3 seconds and measure current. But I don't know if the pump is accessible...
  10. It is not as you say. Starting, It will be: KVA = 415 * In * 8 * 1.71/1000 KW = 415 * In * 8 * 1.71 * 0.25/1000 You have to consider cos phi will be round 0.25 at start. Inrush current will be much higher that you measured, round 8 times nominal current.
  11. As I said before, you only need a solar VFD and 15 Kwp of solar pannels. No batteries, no charger, no inverters... https://www.zuendo.com/ls-solar-trifasico-380-v/2863-variador-de-frecuencia-solar-trifasico-11-kw-ls.html
  12. Mmm. You would need 415x1.73*77.6, or 55 KVA... You only need a DC VFD, no inverter is needed
  13. No inverter is needed for a PV Geyser, only solar pannels and a resistor acording them. Nowadays, comparing costs of both technologies, i only woud install pipes if I hadn´t enough space for PV.
  14. Yes, with only solar pannels and this kind of resistor, one can have three levels of Power: 2 Parallel: 1500 w Only one resistor: 750 w 2 in series: 375 w https://www.amazon.es/Calefacción-Inoxidable-Alimenticio-Resistencia-Calentador/dp/B01EHWIZ76/ref=sr_1_1?ie=UTF8&qid=1552320774&sr=8-1&keywords=resistencia+48v Depending on radiation, one or the others can be adopted. If you like spanish, jeje, you can read this: https://adnsolar.eu/viewtopic.php?f=17&t=146
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