DC Power for Backup

by Rik
(Fontana, California)

I made an aeroponics system and am 1 week into it. I've been concerned about power outages. I have a box from at&t that has an AC input and converts it to DC to power the system in case of power outage (to give a customer access to a phone line at all times). I bought a cheap DC water pump and tested the box (which has a small 12 volt battery inside). My test showed 4 hours of on time- battery alone. I was thinking of putting it on a larger battery and running some computer fans also in case it were to happen. My question: Are there any reliable brands out there for DC equipment. Is there any formulas or sights that might help me with a carbon filled 4 inch tube with two different types computer fans on each end. I have tried different scenarios with just changing polarity to exchange air between 2 10' x 10' rooms. Thank you for your time.

Answer: Rik- most hydroponic gardens can survive short power outages with little negative affect. The main exception, of course, would be an aeroponics system. With nothing around the roots to act as a storage buffer for moisture, a power outage affecting your aeroponic water pump can begin to damage your plants within the first hour. Your plan to use a 12 volt battery to power your water pump is excellent, as four hours should be enough to get you through the majority of power outages you might experience.

If you are running your pump constantly, you will be able increase the life of the battery four fold by using a 5-1 timer. A 5-1 timer is a timer that turns your pump on for one minute every five minutes. These timers can be purchased at your local hydroponic gardening store, or else can be ordered through a company like Discount Hydroponics or Alternative Garden Supply.

In my opinion, powering fans would be much less of a concern. While the conditions may not be ideal, plants can tolerate no air circulation, low CO2 levels, and high humidity for much longer periods of time without suffering any appreciable damage. If you are still interested in providing some air movement, check out:

backwoodssolar.com/catalog/fans.htm

Or any other website dedicated to solar powered equipment. These types of fans and equipment are designed specifically to run off a 12 volt DC power supply (which a solar panel would than keep charged up, if you were to hook up the solar panel component). Unfortunately, I do not have any personal experience with setting up a DC powered backup for anything, but these websites would be the perfect place to get the right kind of advice for the project you are interested in completing.

A couple of additional things to keep in mind- you will want to make sure the timer for your light has a battery backup, so any plants in the flowering stage can resume their appropriate light cycle without any change or interruption. Also, for anyone using a deep water culture type system where the roots remain permanently submerged, you may want to put the air pumps in your nutrient reservoir on a battery backup. I hope this helps you out Rik, and Happy Growing!