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Excess Energy Saving from a constant energy source.

  1. Jun 19, 2016 #1
    Hello everyone.
    So i live in Lebanon, and since a long time now we have constant power cuts, almost half the day each day. For that the Lebanese made up a system in which each neighborhood has power generators providing electricity to the residents when the power is out. Usually the owners of these generators would charge an average of 100$/month for a 5A/220V AC subscription. You'd have circuit breakers on the street for 5A or 10A depending on the subscription, so it doesn't matter how much energy you use, you will have to pay the same, usually i use 2.5A on average and the excess energy goes as extra profit for the owner of the generator. My question is, how would it be possible to use the remainder of the 5A perhaps to store the energy when not needed and then when energy is needed to go beyond the 5A limitation.
  2. jcsd
  3. Jun 19, 2016 #2
    2.5A at 220v is 550 watts of energy on average you want to store. 550 watts for 12 hours a day is 6.6 kwh of energy. Battery prices vary, but it should cost you more than $150 to store a kwh. Battery life varies on numerous factors such as how much you cycle them so that is something you need to pay attention to. The electronics needed might be difficult and/or expensive. I googled it and found a person who seems to be offering a kit that might do what you want, but they are asking 3,000 euros for a 5kwh kit.
    Good luck.
    Last edited: Jun 19, 2016
  4. Jun 20, 2016 #3
    Thank you Evanish for your feedback. I think that this is a good starting point. But i have to give further precision. The power outage lasts 6 hours followed by 6 hours of electricity (around 15A breaker), so there will be no need for a big battery bank, a small battery bank capable of producing 2-3 Amps on top of the 5 A for a couple of hours enough to run the washing machine, a dryer or 1 AC unit would be ideal. My question is let's say i get a battery and a DC to AC inverter how should i wire it in a way, that the inverter would only send the right ammount of electricity on the same line as the generator is it even possible i mean can i put 2 sources of AC current on the same line or would i get a catasrophic failure since they the current might be out of sync and u get one in the positive phase while the other in the negative phase.
  5. Jun 20, 2016 #4


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    You are asking for help to do some seriously dangerous stuff .... I would STRONGLY advise you to reconsider your plans
    and keep the 2 systems separate. You are also underestimating the power requirements of a washer, a drier or AC unit
    and a battery's ability to provide useful power for any length of time

  6. Jun 20, 2016 #5
    Perhaps you would benefit from something called an off-grid inverter. Charge the batteries when the gird is up, switch over to the off-grid inverter when it's down. I haven't researched them enough to know if they will meet you need, but it's something you might want to look into although I think it's pretty expensive.

    Here is something else that might interest you.
    Last edited: Jun 20, 2016
  7. Jun 20, 2016 #6

    jim hardy

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    Unless those are gas appliances, they are LARGE loads not practical for a battery.
    Here in US $300 will buy a 3kw gasoline generator. Even that's not enough for an electric dryer but it'd run a small A/C .
    If your dryer is propane or natural gas fired then you only need maybe ½kw for the motor.
  8. Jun 20, 2016 #7


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    Thread closed for Moderation...
  9. Jun 20, 2016 #8


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    @A Chamas -- You will only be able to run your major appliances when the AC Mains power is on. It is impractical for you to store enough energy to run them when the AC Mains power is off. You can charge 12V batteries when the AC Mains power is on, and use that 12V battery power later for small loads like a fan and a reading light and a radio and small portable TV. You could also add a solar panel and 12V power converter to help you when the power is out and the sunshine is strong.

    This thread will remain closed due to the inexperience of the OP and the dangers of such people trying to do DIY AC Mains projects.
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