solar panel to run minnow bucket aerator

Discussion in 'General Electronics Chat' started by catclaw, Aug 12, 2012.

  1. catclaw

    Thread Starter New Member

    Aug 12, 2012
    I am using a solar panel to run a minnow bucket aerator to aerate a tank containing some fish. The panel outputs 12+ volts. The aerator is normally powered by 2 D cells so I added a Dc to Dc to provide about 1.3 volts to the aerator motor. With sun on the panel, the aerator works fine once I push the start switch to on, but if a cloud causes the aerator to stop, it will not 'self-start' once the sunshine returns. It starts easily if I push the switch off and back on. I set the voltage to 1.3 volts to slow down the aerator motor as it really pumps fast and I want to prolong the units life. I tried adding a capacitor but it didn't seem to add anything. I am retired and piddle with this kind of stuff, but I lack any real knowledge so forgive my errors.

    Question: How can I get the motor to self start without me switching it off and then back on? Why doesn't it self start? I guess I could add another panel but the DC to DC probably would block any benefit from the second panel?? I want to add a timer and just run the aerator about a hour a day,but thought I should not complicate this effort until I solve this issue. Any help or ideas are welcome and thank you in advance.
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    Piddling at any age should always be encouraged. :D

    It is curious that the unit doesn't self start after a cloud. I might guess the voltage drops so much the motor stops turning and stalls in place. As the cloud goes away the solar cell voltage goes back up, but the stalled motor looks like a short to the DC-DC output, and once the DC-DC output limits it needs the motor removed to recover. If you have a voltmeter you could verify this.

    It can start when reconnecting as the cap on the DC-DC output is now charged and can give a burst of power to get things moving. When a cloud comes by the cap isn't charged and can't give that starting kick.

    The timer to run it for half an hour a day may be a way to work around the cloud issue. Instead of running for half an hour a day run for a minute on/a minute off for an hour (or longer) a day. That way if a cloud comes along it still restarts.
  3. ramancini8

    Active Member

    Jul 18, 2012
    The output voltage of 2 D cells is 3 volts, so the DC to DC converter output is too low.
  4. BMorse

    AAC Fanatic!

    Sep 26, 2009
    He stated that he reduced the power output on purpose to slow the motor down on the aerator pump.....
  5. Bernard

    AAC Fanatic!

    Aug 7, 2008
  6. ramancini8

    Active Member

    Jul 18, 2012
    That may be true, but motors generally have starting problems when hooked to low line voltages. Try the motors at 3 volts and see if they start corrctly; if so, you need a different method of slowing the motor down. Texas Instruments has a relay switch that gives full line voltege to pull the relay in, and then drops to a lower voltage to hold the relay in. Something like this might be required here.