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Run a submersible pump on battery ?

Discussion in 'Power Electronics' started by vassock, Feb 8, 2016.

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  1. vassock

    vassock

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    Nov 30, 2015
  2. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    Sure, depending on how long you expect it to run.
    The battery you linked is 6 volt (you need 12v) and of a rather small capacity.

    The lugs are male spade terminals.
     
  3. vassock

    vassock

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    Nov 30, 2015
  4. davenn

    davenn Moderator

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    Sep 5, 2009
    ok so that battery is 12V @ 5Ah so that equals under ideal conditions 5Amp drain for 1 hour, alternatively 1A drain for 5 hours

    your pump is rated at 12V 2.5W

    Watts / Volts = current drawn

    2.5 / 12 = 200 mA ( 0.2 A)

    you now have all the info, you do the other maths :)


    Dave
     
  5. vassock

    vassock

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    Nov 30, 2015
    So it will work for about a day?
     
  6. davenn

    davenn Moderator

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    give or take a bit ... prob a little less as you have to figure in that the battery wont stay at a constant voltage throughout the whole discharge period ... it will be slowly dropping

    Approx. 20 hrs would be a good estimate
     
    Last edited: Feb 9, 2016
  7. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    Good post Dave.

    Vassock; If this is for an aquarium, you also need to think of maintaining the water temp.
     
  8. vassock

    vassock

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    Nov 30, 2015
    It is, but fish can generally survive for a while in cold water. It's the lack of aerated water that kills the fish first.
     
  9. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    Very good then.
    I'd make sure your "home made generator" doesn't over charge the battery, or it will not last very long.
    A battery tender or trickle charger is probably the way to go.
     
  10. vassock

    vassock

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    Nov 30, 2015
    So I have the battery, the pump, but what about the power source? Any recommendations?
     
  11. ChosunOne

    ChosunOne

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    Jun 20, 2010
    The alarm industry has used small 12VDC independent power supplies for a long time now. This model, the AD12612...
    http://www.shieldlab.com/forum/index.php?action=search2
    is more than sufficient to handle your pump and comes with leads to attach to your 12V battery. Markets at this site for $20, (And thanks for letting us know you're in the USA), but you might be able to find a better price by googling the model number.

    It does require a 16.5VAC 40VA transformer, which is plugged into an outlet and everything from there is low-voltage wiring...
    http://www.shieldlab.com/forum/index.php?action=search2 Markets here for ~$13, bringing the total price to ~$33,

    But you can definitely find a better price on eBay, or Google-search using "16.5VAC 40VA transformer." For example...

    http://www.ebay.com/sch/i.html?_odk...r.TRS1&_nkw=16.5VAC+40VA+transformer&_sacat=0
    At the moment there's a $7 transformer available that with free shipping, bringing the total down to $27

    If you want to be clever, there are old obsolete alarm control panels, still completely functional, that use the same transformer and have an Aux. 12VDC output of about 500-600mA off the PCB terminal strip.
    http://www.ebay.com/itm/Honeywell-A...994705?hash=item3ab348c851:g:9G0AAOSwCypWpSr2

    You could repurpose it to use just the power supply portion of the panel and save a few bucks. The only downside would be the bulkier PCB, but it would bring the total cost down to $21.

    I used to do that all the time when I upgraded working alarm systems: Used the old panel, instead of charging customer for a new aux power supply when one was already on site.

    EDIT: If low cost is a real consideration for you, I have a bunch of functional PCBs with 12VDC outputs, and transformers stashed away from my years as an alarm tech. Let me know, and we'll work something out. One caveat, I'm away from home and won't be back before the weekend at soonest.
     
    Last edited: Feb 9, 2016
  12. ChosunOne

    ChosunOne

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    Jun 20, 2010
    Just had another thought: I didn't think about this earlier because I'm so used to using power supplies designed to connect to backup batteries that I didn't really think too much about using a battery trickle charger along with a backup battery---

    How, exactly, would you hook it up to work continuously? If you just connect the charger output in parallel with the battery, and also in parallel with the pump, then the charger is running a load and simultaneously trying to keep a battery charged. It "senses" the Lead-acid battery state of charge by sensing voltage--but running a parallel load will affect the voltage it "sees", and It will probably overcharge the battery before long.

    That's why power supplies designed to use backup batteries have the battery leads and power output on different circuits.
     
  13. vassock

    vassock

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    Nov 30, 2015
    I am getting "Did you forget to put something to search for?" when I click on your links.
     
  14. vassock

    vassock

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    Nov 30, 2015
    How will this solve the biggest problem: power generation? Solar panels are too expensive for this project. I need some sort of crank generator. It doesn't have to switch automatically. I can hook it up, crank up the power, and then connect the pump.

    I guess I'd have to buy a car alternator and hook that up somehow.
     
  15. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    How about a spare car tire or compressed air tank with an air hose to supply your aerator? (No electric power used)
    That'd last at least a day.
     
  16. vassock

    vassock

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    Nov 30, 2015
    Already have that. Was looking for an alternative.
     
  17. ChosunOne

    ChosunOne

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    Jun 20, 2010
    Oops, my bad. I navigated to eBay through the Shieldlab site to those first two links: Not the way to do that. Sorry. The 3rd and 4th links connect you okay.

    1st link for AD12612 power supply on eBay : http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=AD12612&_sop=15
    This listing contains a unit currently available for $24, or $4 more than I found when I first posted.

    2nd link, for 16.5V 40VA transformer : http://www.ebay.com/sch/i.html?_odk....l1313&_nkw=16.5VAC+40VA+transformer&_sacat=0

    This is going for $7, free shipping: $6 less than what I found above.


    So a net difference of $2 less--which means that if you have time, you can see what the current market price is and wait for a good deal to save a few bucks. That's assuming you shop on eBay or other online site like I do.


    I suggested this assembly, the AD12612 power supply, 12V 4Ah battery, and 16.5VAC 40VA transformer as a way you can power your pump from your 120VAC line power outlet. Your pump document claims it uses 2.5 Watts, and the transformer & Pwr supply together may bring the tally up to maybe 4 W (?). That's about what an incandescent fridge light draws.

    A car alternator AND voltage regulator, plus the mechanical assembly you'll need to crank it, MIGHT pay for itself in electricity savings in a few years. Sorry, I just don't get the economy of that. Is this for a place that doesn't have line power?
     
  18. Gryd3

    Gryd3

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    875
    Jun 25, 2014
    Manually generating the power will be incredibly tiring...
    As far as a solar panel is concerned, you need to size it to the load, not the battery.
    If I read correctly, the pump is a 2.5W model.
    So... let's say you can run a voltage regulator at 80% efficiency, you are up a little over 3W...
    But, worst case, you only have sun for 8 hours in the winter months maybe?
    So you need to generate a full day's worth in 8 hours, so a 10W panel would be required if you want to run the pump 24/7 . (This is in ideal lighting conditions though...)

    Anyway, price them out and see if it's worth it. No one here can tell you it's too expensive if you are willing to spend the money on it.
    Although I would be careful with an air compressor... don't they usually have lubricants that could leach into the water?
    Is your tank large enough to put in plant life that could assist in this?
     
  19. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    That's the million dollar question.

    You could try and make some sort of dynamo to produce electricity, but it doesn't sound feasible.
    It might be more practical to just make a device that would directly pump air. You could probably have something like an elevated water tank that'd trickle water down and have a drain spout that would siphon off the excess water level?
     
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