Power Supply

Discussion in 'Tech/Mech General' started by Wildge, Jan 17, 2015.

  1. Wildge

    Wildge Funster

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    :( Does anyone know of an alternative power supply when not on ehu. Needs to be available to run Medical equipment overnight so gennie not an option. Seem to think I have read somewhere on here about ? Power cells ????. Or have I got that completely wrong (n) Already have 80w solar and twin batteries .
    Please keep it simple guys :eek:
    thanks Jude
     
  2. CWH

    CWH Funster Life Member

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  3. hilldweller

    hilldweller Funster Life Member

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    Sun, Wind, Chemical, Gennie. Take your pick.

    The socially nice one is chemical, turning alcohol into electricity silently. See Efoy.
     
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  4. tonka

    tonka Funster Life Member

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  5. TheCaller

    TheCaller Funster

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    A fuel cell would be an expensive but silent & fairly reliable option.

    One or two members have them.
     
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  6. Peter A Forbes

    Peter A Forbes Funster

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    If it needs to be separate from the rest of the motorhome electrics then fit a third battery and charger.

    If you need more than a battery will provide, there aren't many options for night use.

    Peter
     
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  7. Wildge

    Wildge Funster

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    (y) Thanks for all your input. Have just been looking up the actual energy required and the machine uses 700w .Not being at all technical could this run all night with a genny to recharge next day ??
     
  8. scotjimland

    scotjimland Funster Life Member

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    presumably you are thinking on running from a 12vdc - 230vac inverter.. ?

    700watt , dived by 12v to get the amps..

    700/12 = 58amps,

    this would kill an 80ah battery in less than an hour..

    to run all night, 8 hours x 58amps = 464ah .. so you would need a battery bank of almost 1000ah .. :Eeek:

    you need to think again.

    Without EHU, A 1kw petrol / LPG fueled generator, or an Efoy fuel cell is the only practical solution ..
     
    Last edited: Jan 17, 2015
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  9. hilldweller

    hilldweller Funster Life Member

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    AND you have to take into account "medical", certainly a gennie will fail sometime with those hours, then what happens ?
     
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  10. scotjimland

    scotjimland Funster Life Member

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    same as what happens at home during a power cut ... or on a site with EHU and it trips out ..

    to be safe you would require a UPS that could maintain the supply for say 1 hour with an alarm to alert the carer that the genny had stopped or the mains ehu had tripped..
     
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  11. TheCaller

    TheCaller Funster

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    700 watts is a lot of power, even for mains powered equipment. There aren't that many pieces of equipment, other than heaters of some sort (kettles, hair dryers, toasters etc) that draw that sort of power continuously. I think that figure needs checking - it might be a maximum start up draw, or maybe the kit only runs intermittently.

    The largest Efoy fuel cell only produces 110w continuous output.
     
  12. Red Dragon

    Red Dragon Funster

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    Hi we are heavy electric users and into Skiing and wilding so I bought an Efoy (140) I have a battery bank of (260amp/hr) 2 batteries and a 100watt solar so we can be totally independent if needs must.
    The Efoy monitors my battery bank and when it lowers to 12.3volts the Efoy kicks-in and recharges the battery bank at approx 5/6amps hr,so it would cope with your situation nicely and also it very silent.
    Hope that helps.(y)
     
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  13. scotjimland

    scotjimland Funster Life Member

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    yes,, good point, perhaps the OP could check and or take a photo of the data plate
     
  14. Red Dragon

    Red Dragon Funster

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    Sorry just re-read those figures you would need a significantly larger battery bank to get you through the night time.
     
  15. Wildge

    Wildge Funster

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    (y)Thanks for all the replies ............Have not got the equipment yet so can only go on what is published :whistle:
    Back to the drawing board ............................ or looks as though it will be EHU from now on :groan:
     
  16. pappajohn

    pappajohn Funster Life Member

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    Woah....that's novel.

    I change alcohol into water and gas
     
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  17. hilldweller

    hilldweller Funster Life Member

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    70 watts from Efoy, 700 watts out, that's not going to work, depending on how long the 700 watts is running.
     
  18. Daifuse

    Daifuse

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    My wife says I do the same - but I reckon it' the dog, PHEEWWW!
     
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  19. Gizmouk

    Gizmouk Funster

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    hmm. Depends.
    How critical is the medical equipment ? i.e - if it loses power, what impact would it have on the patient over what period of time ?

    The 700W you quote:
    Is that the "boiler plate" figure ?
    I assume it's 230V AC ?

    Who's medical equipment is it ? Yours or "on loan" ?

    Without knowing the above:
    I wouldn't recommend reliance on a generator - far too much that can go wrong, even down to silliness like running out of fuel.
    If you go down the generator option, then using an online UPS downstream of the generator will increase integrity. Although to maintain a 700W, you'll need a fairly hefty UPS (and battery/s) to maintain any kind of useful autonomy - I can do the calculations if you require.
     
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