If you have a fountain in your backyard, a submersible pump is probably driving the water. Small pumps for outdoor fountains usually don't draw much more than 1 amp of current. That's about the same, or less than, a 100-watt incandescent light bulb. If you leave your fountain on all the time, though, this power draw can add up. It's an unnecessary addition to your energy bill, because you can retrofit your pump with a solar-powered one that doesn't cost anything to operate. You can also keep your pump and hook it up to its own solar electric system.
Things You'll Need
- Solar-powered submersible pump kit
- 120-volt electric submersible pump
- Solar panel
- Charge controller
- 12-volt deep-cycle battery
- 400-watt inverter
Unplug your submersible pump, remove the water tubes, and take it out of the fountain. Fit the tubes on the outlets of a solar-powered pump and put it back where the old one was.
Place the solar panel that came with the pump kit in a sunny location on the ground or on a fence close to the fountain. Run the cord attached to the pump to the panel, and plug it in. The pump will now operate whenever there is enough sun to sufficiently energize the panel. When the sun sets, however, the pump will stop operating.
Try an alternative way to supply solar power to your fountain: Leave your old pump in place and construct a small solar-electric system to power it. Set up a 15-watt or larger solar panel in a sunny location. Fifteen watts is the minimum panel output needed to charge one 12-volt battery. You can use a larger panel if you want faster charging, but be sure the panel you use has a rated output of 12 volts, to match the battery.
Connect the panel leads to the input terminals of a charge controller. Its purpose is to prevent the battery from overcharging, and also to prevent the battery from back-feeding the panels when the sun isn't out. Most panels have blocking diodes to prevent back-feeding, so if you plan to leave your pump on all the time and there is no danger of the battery overcharging, you can dispense with the charge controller.
Wire the charge controller to the terminals of a 12-volt deep-cycle battery. If you don't have a charge controller, connect the leads from the panel directly to the battery terminals. Make sure you connect the red wire to the positive terminal, and the black wire to negative. Leave the battery connected to the panels for several sunny days to charge it before you plug in the pump.
Place a 400-watt inverter next to the battery, and connect the red input lead to the positive terminal and the black lead to the negative one. If the inverter has a selector that toggles between 6 and 12 volts, set it at 12 volts. Unplug the pump from the house outlet and plug it into the inverter, then turn the inverter on. The pump will operate day and night, as long as the battery has a charge and you don't turn off the inverter.
Tips & Warnings
- Place the charge controller, battery and inverter in a cool location under a shelter to protect them from sun and rain. It's advisable to keep the battery in a plastic case.
- You can use an inverter rated for less than 400 watts if you want, but it will probably won't be less expensive.
- If you have several consecutive cloudy days, or you leave for an extended trip, turn off the inverter so the pump doesn't drain the battery. If the battery drains completely, you will need a new one.
- Photo Credit fountain image by Bruce Shippee from Fotolia.com