diy solar

diy solar

Recent content by 120vjohn

  1. 120vjohn

    Solar panel shading and parallel versus series connections

    For short, is a trade off between cell size, geometry and shading. If you split your array in more strings with smaller cells, probability that one equivalent cell to be completely shaded is negligible, if the cell is a long thin strip, probability to be completely shaded is lo. Smaller cells...
  2. 120vjohn

    Solar panel shading and parallel versus series connections

    At what age she died, was natural death, illness or accident? About health issues, i am a health care specialist that live offgrid. Now days are new health challanges some of them can be managed whit some know how. E.G. some digestive cancers are related with H.pylori chronic infection, I...
  3. 120vjohn

    APC Smart-UPS 1500VA with LiFePO4 Batteries

    3.45 in float is too hi for LFP, expected life is about 3 years. LTO last longer in hi float voltage, but is expansive. Large lead acid are also good, E.G. NSB100FT agm, or larger, or tubular plate gel, or OPZv, you can also use individual lead acid OPZv cells
  4. 120vjohn

    Melted MC4. What happened?

    If connectors are good quality and well paired this can occur due to corrosion somehow water seeped inside and corroded metal. Also be sure that is not overloaded by paralleling strings on it, be sure it was well plugged in, wire was correctly pressed, or soldered, wire was not corroded when it...
  5. 120vjohn

    Got Busted by Electrical Power Police..Now Need help with Permits

    Some meters register injected energy as consumption, this is the way company prohibit injection. Any grid tied inverter has built in anti island protection, but some providers ask for external protection, an anti island kit agreed by that company. Fire safety regulations are in place for PV...
  6. 120vjohn

    APC Smart-UPS 1500VA with LiFePO4 Batteries

    For most 36v UPS`s final charge voltage is 42v for lead acid is 2.33v/cell. if you use 10 NMC cell in series is 4.2v/cell, hi not last long. To use 12 LFPcell in series you need 40v for 3.35v/cell, at 40 v you can also fit 10 NMC cells in series. You can adjust charging voltage, by modifing...
  7. 120vjohn

    Do LiFePO4 batteries ever need to be fully charged?

    All lithium batteries last longer if not full charged, if you have a BMS that allows final voltage and cell ballancing to be set , set it at 3.35-3.37v/cell, if you not go higher than that imballacing may occur in years at LFP, at LTO is faster, but i do not need to manually ballance long...
  8. 120vjohn

    Possible to determine watts of panel when testing it?

    That battery must good enough to take entire current generated by that panel, but you can add a load to be sure that entire available power is absorbed. For mobile testing a relative small LTO battery is better because it can be charged at over 10 c. This method have some limitations if you try...
  9. 120vjohn

    Got Busted by Electrical Power Police..Now Need help with Permits

    Islanding maybe a problem if multiple systems are connected to that section of grid, and provide enough power for local load. I had that problem with several over 10 kw systems that power an entire street in island status. In that case total power was around 100kw, if a line man attempts to...
  10. 120vjohn

    Possible to determine watts of panel when testing it?

    You can mesure the live power using a dc/dc that read input voltage, and keep it stable by a feedback loop, you can use a TL494, feed input voltage on inverting input, reference by a adjustable divider on non inverting input, and use buck or boost topology for force. Place an apropiate resitive...
  11. 120vjohn

    Got Busted by Electrical Power Police..Now Need help with Permits

    Energy price rises in US? in Europe is expansive that offgrid is cheaper than grid. If feed in to the grid is no allowed, you must go offgrid. You may tailor your system in accordance of your needs, conductors cross section must be adequate. I use a quite hi voltage to avoid thick expansive...
  12. 120vjohn

    Supercapacitor or light load startup to save inverter surging from welding/electric stove

    DC battery seems to deal with your inrush currents, 12kw inverter is enough for one appliance at a time, problems occurs in worst situations of same time start. Pay attention at inrush reactive power, it can be mostly reactive than active. IF you use a hi voltage battery some appliances can...
  13. 120vjohn

    Convert Solar to Crypto/Research - A Heating that pays you! An option to use spare electric energy

    ASIC miners are for sale or must be custom built? How can we use sun power that is available few hours a a day? Hydro may be ok. What internet band is needed to mine? Battery pay itself if used for mining? What can do with 30kwh battery/ 3 kwp pv system?
  14. 120vjohn

    Question regarding capacity testing of LTO cells

    I use LTO cells from 4 years, in solar systems 10c rate is an exception, if you have 10kwh 10 c is 100kw, for such system at least 100kwh battery is used, 1c rate is common peak load for LTO 1c is nothing, even under 10c only is below 30 percent SOC may drop under 1.9v. Such drop means defective...
  15. 120vjohn

    Question regarding capacity testing of LTO cells

    If you use a BMS lo cut off at 1.9v is ok, it takes in account the lowewst cell, if you do not use BMS 2.1v /cell is optimal, it represent the beginning of lower bend, from 2.1 to 2v is a reserve that can you use if you have no other option.
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