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[Solved] How to change alternating current to direct current? How to do it??

Cezar0823 891 9
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Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
  • #1 21745586
    Cezar0823
    Level 8  
    Hello
    I have energy storage charged from PV panels.
    But winter is going and they produce poorly and electricity is needed :)
    I don't have mains power, only a generator.
    What I would like to obtain:
    As the inverter doesn't want to charge my storage from the genset - I don't know why; it shows 50Hz with pennies and a voltage of 240V.
    I decided to 'straighten' this current and connect it as DC instead of PV modules.
    I used a full bridge, followed by a capacitor from the description to 400 V and plugged this in instead of the panels, and it doesn't work as I wanted.
    I should add that the genset is 3-phase and I would like to load it evenly (use all phases) and, therefore, get 3 times the charging current.
    Does this have a chance of working?
    So far nothing has exploded apart from the capacitor, but this is probably due to the fact that I've connected temporarily 'dry', with no load/power consumption.
    It charges poorly, the genset works strangely on this solution and I don't know if it's being overloaded by my invention or if something is "fighting" with itself.
    I hope someone has understood me and is able to give me a hint.
    Best regards, Czarek
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  • #2 21745603
    bratHanki
    Level 39  
    What voltage does this energy storage have?
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  • #3 21745616
    Cezar0823
    Level 8  
    48 V, lifepo4 320 Ah.
    6.2 kW inverter.
  • #4 21745663
    Aleksander_01
    Level 43  
    @Cezar0823 leave it alone or you'll be mollifying the shed and it'll only be a problem. You are making basic mistakes (you want to charge with too much voltage).
    As for the almost academic discussion, no one has mentioned the choke and it filters the current (amperage) and the capacitor filters the voltage.
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  • #5 21745751
    Cezar0823
    Level 8  
    In fact, the situation was a bit dangerous, fortunately it ended with a boiled capacitor.
    And it was supposed to be so beautiful and simple.
    The situation was described to me by an Elektroda bot and no knowledge was spared.
    https://www.elektroda.pl/rtvforum/topic4152289.html

    Added after 2 [minutes]:

    Thanks for the information.
    I'm back on the ground
    and looking for proven solutions for charging energy storage without access to the mains.
    Regards
  • #6 21745827
    Krzysztof Kamienski
    Level 43  
    @Cezar0823 After all, you have a generator. Use a suitable charger adapted to your battery bank. Except that, for me, this is heresy. And why, you can guess.
  • #7 21746619
    Cezar0823
    Level 8  
    Instead of guessing I got the info from the bot; hopefully factually correct as it explains a lot.
    I tested the generator mode before trying with the rectifier and it didn't turn on; it saw the generator voltage and frequency, even turned on Bypass mode, but didn't charge.
    But I got an answer to that from the bot too, as to how to solve - at least try - safely.
    I will test it at the earliest opportunity.
    When you don't have enough experience and knowledge, sometimes you can mess something up :)
    For me, enough knowledge already.
    Thanks to all who have contributed.
    Regards
  • #8 21866221
    ivanbul
    Level 2  
    Hello. The reason the generator is not working is, generally, because of two main reasons:

    1. Inverters can be quite picky with waveform. If you have a small generator, the waveform will most surely be quite off from the sine wave or frequency could also be off, so the inverter "decides" to reject it.
    2. Because of the way inverters work, they introduce harmonics which "disorient" the generator and introduce variability in its waveform and voltage/frequency, taking you to the previous point. As a rule of thumb you should oversize your generator as a minimum of twice the inverter rate power, unless you have a inverter generator. Once again, the smaller the generator the more affected by harmonics it will be.
    3. I think inverter quality also plays a significant role here, some old or generic inverters could face more problems handling generator AC input.

    I already encountered the same problems and rectifying AC from generator to DC through PV worked just fine, just make sure in the user manual that DC current and voltage are not larger than what your inverter PV input can handle.

    Other solution as somebody else pointed out is to use a battery charger, but since I'm using LFP batteries and I don't have access to more sophisticated chargers I decided not to screw them up and let the inverter manage them, so I can't give you any advise.
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  • #10 21884025
    Cezar0823
    Level 8  
    i ended up buying a genset with an inverter, now everything runs as it should, 4 kW available from one phase
    everyone is alive, no damage
    maybe one day I will play with it again
    kind regards
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