Help! Maybe I'm dense or have been up one to many nights at work but...

DisplacedTxnDisplacedTxn Registered Users Posts: 1
I'm having trouble figuring out what I need for what is hopefully a simple setup.  I am trying to set up a solar panel to charge a 12V battery to run a 2.5 amp Rule 500GPH bilge pump to provide aeration for a water garden/fish pond.  I am also trying to do this as cheap as possible since I have already sunk plenty of $$ in buying solar water pump kits online.  Looks like 500 GPH is the lowest I can go setting it up with a bilge pump (my ideal would be 150-200GPH) but I can add onto the pond to compensate for that.  

My problem is trying to figure out what i need to set this up.  Maybe it's been too long since I took physics, or I'm particularly dense this week, or I've spent too many hours awake working night shift, but I am having trouble figuring this out.

I can buy 100 watt solar panels from harbor freight or bass pro easy enough.  Same for 12V rechargeable deer feeder batteries.  Not sure what I need past that or if that battery will do what I need, but goal is to have the pump run constantly from an about an hour after sun up to a bit before dusk so the mosquitoes lay larva in the pond and my fish eat them all.  (battery =>

  I had bought a kit with a 10W 12V solar panel pump kit ( which burned out in 2 weeks.  If it had kept working though it would have been about perfect (other than signifigant power drops with each hint of cloud causing the pump to constantly switch on and off.

If someone can please walk me through what I need to set this up and explain it like I'm an idiot, I would really appreciate it.


  • NANOcontrolNANOcontrol Registered Users Posts: 202 ✭✭✭
    You normally do this with with what is called a Linear Current Booster and no battery.  That is just a fancy name for a switching power supply that will maintain a minimum panel voltage.  If panel W is sufficiently much larger than needed, maintaining a minimum voltage is not needed.  What failed normally has a decent life. Extreme cold temperatures can raise panel voltages or this is just infant mortality. These electronic pumps tend to have a good voltage range.  Replacement pumps like these are in the $20 range and I suggest you try again. You could add a buck converter and set it to 12V and this will extend the running times. I frown on panels this small as a 280W grid tie panel can be had for $170 with a $10 buck converter and be more successful in more lighting conditions.
  • PhotowhitPhotowhit Solar Expert Posts: 5,658 ✭✭✭✭✭
    I have a friend who used a similar unit with a 65 watt panels. Though the system says 12 volt, the motor does say 12-24 volt. I had the panel already and purchased the 12-24 volt pump off eBay for @$10 and 6 weeks (from China) It worked well for her in a hydroponic application, though intermitted running.

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former, 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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