Battery size

Discussion in 'The Projects Forum' started by jonnydolt, Feb 12, 2016.

  1. jonnydolt

    Thread Starter New Member

    Oct 23, 2015
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    Hi I am wanting to build a couple of timed open/close doors for the chicken pens I would like to run them on solar power with a small 12v motor and battery.The motor would be high torque (10kg) 2rpm with a simple pulley and twine set up to raise an aluminium door .I will get a pulley size so it takes around 2 minutes for the door to open .The Motor is rated at 2-3 amps and I "think" I would need a battery pack of at least 200Mah for it to open and then close once.Based on this if I got a 4000Mah battery it should run at least 8 days without sun to recharge the battery does my logic sound correct? Please find links to the motor ,battery and timer ...I understand that the timer will also draw a small amount of power.................. http://www.ebay.com.au/itm/281761621916?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT ................... http://www.ebay.com.au/itm/141518885160?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT ................... http://www.ebay.com.au/itm/1x-12V-D...118696?hash=item4184c10da8:g:Fo0AAOSwiLdWAHhh Many thanks in advance for your time
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Your motor is 12V 3W, thats 250mA running current, not loaded, so your 4Ah battery will last 16hours continuous use, if its used for 4mins per day, thats open and close, thats 240 open/close times maximum, possibly less under load.
     
    Last edited: Feb 12, 2016
  3. Evanguy

    Member

    Dec 21, 2014
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    I would use one of the cheaper end 30-34aAH deep cycle betteries if it was me.
    lead-acid sealed type.
     
    Last edited: Feb 12, 2016
  4. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    Post #1 said the motor was 2-3 A, but the ebay link says 2-3 W which makes much more sense. 3 W x 2 m x 2 operations per day x 8 days = 96 w-m, or 1.6 watt-hours, or 0.133 amp-hours at 12 V. That's not much. The majority of the system power will be consumed by the timer. 2 W x 8 days = 384 watt-hours, or 32 A-h. That's a lot. 160 mA seems like a lot for such a simple timer, but that might be the power required when the output relay is on.

    My guess is that the total timer power in your application is very low, and that a 12 V battery in the 3 to 6 A-H range will run the week. I also recommend going with a sealed lead-acid (SLA) battery rather than Lithium. Lower cost, way easier to charge, *sealed* against the elements, etc.

    ak
     
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  5. jonnydolt

    Thread Starter New Member

    Oct 23, 2015
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  6. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Note that the last timer is 12 V AC, 50 HZ. You need clarification on timer current requirements.
    For solar panel I would go for around 20 V OC , @ 100 mA SC. that would be about 6 in. X 12 in.
     
  7. jonnydolt

    Thread Starter New Member

    Oct 23, 2015
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    Like this one Bernard
    http://www.ebay.com.au/itm/5-Watt-1...980978?hash=item3381cc48f2:g:YtMAAOSwrklVAOy3

    found this timer http://www.ebay.com.au/itm/171857064035?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

    per the timer perhaps "50 hz" is a typo but will check

    DIN Rail Digital LCD Power Programmable Timer DC 12V 16A Time Relay Switch New
    Technical parameters:

    Working temperature: -20 ℃ ~ +55 ℃

    Power consumption: <1W

    Input Voltage: 12V 50Hz

    Switching capacity: 16A

    Display: LCD display

    Timing Range: 1 Minutes -168 hours

    Power failure memory: 60 days

    Walking the error: 1s/24h 25 ℃

    Internal battery: 1.2V40Ma (rechargeable battery)

    Timing Views: 17 switch (day / week)

    Dimensions: 86.5 × 36 × 65.5mm
     
    Last edited by a moderator: Feb 14, 2016
  8. Evanguy

    Member

    Dec 21, 2014
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    That timer says 12vdc but then on the pic of the time it shows AC input. and if you zoom in on the pics it says 220-240vac input 16A other info i forget. i didnt notice the add say "pic not of actual item"


    I believe that timer is 220vac in and it switches 12vdc
     
    Last edited: Feb 12, 2016
  9. slackguy

    Member

    Feb 11, 2016
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    you said 200 milli amp hours then 4000 - that's 20x over

    a 350 mAh battery will fly a 2-3 ft. model plane around, to put things in perspective

    or hook it too a sears cordless drill am i right ?
     
  10. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    If a proper timer can not be found, might have to make your own 24 hr. timer that knows that it needs to reverse
    output polarity at one time & straight at another. Will you have limit switches on door ? Timer should only draw less than 1 ma at idle.
     
  11. jonnydolt

    Thread Starter New Member

    Oct 23, 2015
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  12. Evanguy

    Member

    Dec 21, 2014
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    If your going to make the timer your self. i would use no\nc three wire mag switches. those might be,but it didnt say in title.
     
  13. jonnydolt

    Thread Starter New Member

    Oct 23, 2015
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    Last edited by a moderator: Feb 14, 2016
  14. Bernard

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    Aug 7, 2008
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    " a couple of timed open / close doors ". ? one or two motors ? Both open in AM, & close in PM ?
    Reed switches should be fine.
     
  15. jonnydolt

    Thread Starter New Member

    Oct 23, 2015
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    There will be 1 door for each pen .The doors will open at around 6am and close just after dark to ensure all birds are roosting .1 motor per door
     
  16. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    I lashed together a 12 hr. timer to see if there was enough torque from a
    battery operated clock movement to operate a roller switch-- there is. If a 24 hr. movement is not available, then a 12 hr. can be geared down 2:1. Two cams for AM & PM.
    Will need two control units, one timer.
    Starting early morning, door is down, Limit SW D is closed. At 6 AM SW A closes applying power to transistor &
    relay 1, RY 1, Upper relay contacts seem to be missing , should go to +12V. When RY 1 closes, power is applied to the Motor, lifting the door until the door magnet closes L SW C which shorts R1 to ground, causing RY 1 to drop out, stopping Motor. After some time SW A will open. All's quiet until evening when timer closes SW B, causing door to lower. Door 00000.jpg
     
  17. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    We do not really need the relays so might try this circuit. Note that L SW C & D are interchanged. Q1&2 could be 2N2222's, but would rather a 1 A transistor or a FET. Door #2 00000.jpg
     
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