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Discussion in 'General Electronics Discussion' started by Traviskpshelton, Jan 10, 2018.

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  1. Traviskpshelton

    Traviskpshelton

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    Jan 10, 2018
    How long will a 36 V 10 amp hour 360 W hour battery when fully charged run a 1000 W LED lamp. Can I use a modified alternator to charge the battery?
     
  2. kellys_eye

    kellys_eye

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    In theory around 20 minutes. In practise a lot less since, depending on the battery chemistry, you'll be limited on the rate of discharge and/or the depth of discharge.

    An alternator, suitably driven, could easily supply the WHOLE supply current (28A) - many car alternators are rated at 65A so it would run the LED and charge the battery at the same time. Of course you'll need at least a 2hp motor to drive the alternator.
     
    Traviskpshelton likes this.
  3. BobK

    BobK

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    1000W LED lamp? I hope you have eye protection.

    Bob
     
  4. Traviskpshelton

    Traviskpshelton

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    Jan 10, 2018
    If I use a bike to turn the alternator...would th
    thanks for the heads up. Should I use more like lamps with my bike and alt an batt?
     
  5. Traviskpshelton

    Traviskpshelton

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    Jan 10, 2018
    Or can you give me instruction as to what I should do?
     
    Last edited by a moderator: Jan 11, 2018
  6. kellys_eye

    kellys_eye

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    BIKE!! I presume you mean a pedal cycle? In which case 1. you will likely be arrested for using a 1000W LED (as mentioned, serious risk of blinding someone) 2. an alternator on a bike wheel might produce 10W if you're fit! It would be meaningless and pointless.

    Are you sure you know what you're getting in to - I mean a 1000W LED..... are you serious? A very good (and bright) hand held LED torch might have a THREE watt LED fitted.........
     
    davenn likes this.
  7. davenn

    davenn Moderator

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    this thread is close to being closed unless the OP @Traviskpshelton can clearly state what his intentions are

    which currently as @kellys_eye stated very dangerous
     
  8. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    @Traviskpshelton You should tell us what YOU are trying to DO. So far, all you have mentioned is a smallish 360 W∙hr battery rated at 36 V and capable of delivering 10 A∙hr of current into a 1000 W LED load. You wanted to know how long a fully charged battery would run the LED lamp load. Ideally, that would 360 W∙hr / 1000 W or roughly 0.36 hours, about 21.6 minutes. In actuality, the run time will be much less than that, for reasons @kellys_eye stated in his post #2. He also mentioned that an alternator would have to supply 1000 W / 36 V = 27.78 A to power your super-max LED to 1000 W power level. In doing so, the alternator would need at least 1000 W of mechanical power input, roughly 1.34 HP. Round this up to 2 HP to account for conversion losses and to have some power left over for charging the battery.

    So, then you come back and ask:

    This, after asking about attaching an alternator to a BIKE!? If you mean a human-powered pedal bike, you need to realize that a well-conditioned athlete will have trouble maintaining a power output of 50 watts for any significant length of time on a bicycle. A kilowatt is simply not possible. OTOH, if you mean a motorbike or motorcycle, good luck retrofitting an alternator to one of those. Most already have an alternator fitted to provide power for the lights, ignition system, and to keep the battery charged. It is unlikely that you will find a one kilowatt alternator that can be shoe-horned into ANY motorcycle. And most "bikes" today are fitted with 12 V NOT 36 V batteries.

    So, as @davenn said: YOU tell us what you are trying to DO. It sounds to me like you don't have a clue, and are probably wandering into very dangerous territory, as @BobK intimated in post #3. Do you even know how to provide sufficient cooling for a 1000 watt LED?
     
  9. Traviskpshelton

    Traviskpshelton

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    Jan 10, 2018
    Wow thanks guys... Don't give up on me. What I want to do is turn an alternator with the pedal powered bicycle to charge a battery bank meant to power 1000 W LED grow lamps and a water pump in a backyard apuaponic greenhouse. The bicycle was given to me a few years ago and it is a titan Igo electric bike. The motor on the bike is no good... But the battery is. In the spring I will be buying solar panels and two 12 V batteries... But I doubt that will be enough to power the pump and the lights...so I'm looking for alternatives.
     
  10. BobK

    BobK

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    Good luck with that. About 20 hours of pedaling will get you abouy 1 hour of light.

    Bob
     
  11. Traviskpshelton

    Traviskpshelton

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    Jan 10, 2018
    Well that's discouraging... What if I pedal on 20 alternators for one hour? Lol. I kid.
     
  12. kellys_eye

    kellys_eye

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    20 alternators would mean 20x the effort. The human body can produce about 100W (the output from ONE very good quality bike alternator) with a very vigorous pedalling exercise. If you can keep that up for an hour you'd be in the Tour de France team.

    Even solar panels wouldn't be satisfactory. 1000W of solar panel energy would be about one third the size of a decent roof mounted installation..... imagine the cost!

    There is no cheaper/easier alternative than connecting the LED straight to the mains (via its power supply of course) - the 'green' idea that you can get around this is misleading nonsense.

    At best you could use solar panels to charge a battery and use the battery for the night time period but, as stated, the maximum time you can run it for is dependent on how much charge you can get into the batteries before they are used.

    If you want to use the LED for 6 hours, you need 1000W from your solar cells (plus some extra to cover system losses) for six hours too. Assuming you actually GET 6 hours of sunlight......
     
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  13. BobK

    BobK

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    No, you would not be able to push the pedals at all.

    What you need is 20 guys pedaling bicycle alternators, and they can keep your 1000W LEDs going as long as they pedal. You can pay them with the profits from your cannabis sales.

    Bob
     
    Traviskpshelton likes this.
  14. Traviskpshelton

    Traviskpshelton

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    Jan 10, 2018
    Lol! That's awesome...but I don't grow pot. I build aquaculture systems...or isolated ecosystems for production of fish and vegetables in a balanced state of symbiosis. I intend to start a business building customized or "pretty ones" for schools and nursing homes.
     
  15. Traviskpshelton

    Traviskpshelton

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    Jan 10, 2018
    thanks for the info... I do six hours year round. About my pump if I run it in 20 minutes cycles and it takes 120 V 60 Hz and 0.45A ... How much more wattage will I need from solar panels?
     
  16. davenn

    davenn Moderator

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    6 hours of what ?

    so you have given up on the 1000W LED now and going to try a pump instead ?
     
  17. Traviskpshelton

    Traviskpshelton

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    Jan 10, 2018
    No the pump is necessary to lift watter in an aquaponic system... I may not need that much wattage from my light... Where where I live and will be working sunlight is usually pretty good but right here at my house there's a lot of shade. But I definitely have to have a pump running.
     
  18. Traviskpshelton

    Traviskpshelton

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    Jan 10, 2018
    Get six
    I apologize that was supposed to say six hours of sunlight daily year-round at least... As I said I may not need that much light but I still need to pump water 9 feet high.
     
  19. kellys_eye

    kellys_eye

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    Jun 25, 2010
    Your pump is rated at around 55W. Your batteries may consist of 3 x 12V in series (to give 36V) but they could equally be wired in parallel to give 12V at 30Ahr.

    Using a suitable inverter you could power the pump for a theoretical 6.5 hours but, in practise this would be around 4 hours 'at best'.
     
    Traviskpshelton likes this.
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