View Full Version : Continuous Pumping - Switching between Solar Panel and Battery Power
July 1st, 2010, 13:13 PDT
My proposed setup is a solar array and battery bank with a charge controller to run a water pump continuously 24 hours a day. During sunlight hours (solar producing power) I'd like the pump to run on solar and in the evening it to run on Battery. Does the charge controller assist in this? Or do I just wire the system to run 100% on battery knowing that the solar will charge the batteries?
Thanks for your help.
July 1st, 2010, 13:32 PDT
If you use battery, you will need a lot more solar PV to recharge and pump at same time. Pumping directly from solar, no battery, will increase your efficiency. Might only be 6 hours a day, how much water do you need ?
Source: creek, pond, well ?
July 1st, 2010, 13:32 PDT
What you need to do is figure out how much power the pump consumes in a 24 hour period. You will then need to figure out how much solar is required to power that load, remembering that recharging a battery takes ~20% more energy than the battery will give back. You might consider if it worth the effort to pump more into storage over a shorter time (daylight) so that you don't need a battery at all.
The function of the charge controller is to prevent overcharging the battery, so your PV system would put out enough power to run the pumps while the sun is out, and at the same time charge the battery from last nights pumping. In rough numbers, depending on your location, you are going to need ~6-10 times as much PV as the pump requires. So if, for example, the pump draws 500 watts, you might need 3-5000 watts of panels as a quick guess.
July 1st, 2010, 13:40 PDT
Basically, because you want to pump 24 hours per day vs just when the sun is up--The cost for the Solar+Battery system will be ~4x that of a system that just pumped during the day (to a cistern for example). Batteries, charge controller, extra losses, replacement batteries every 3-8 years, etc. -- all add up.
Do you have a pump and power level picked? The pump should be the most efficient you can get and plumbed in the most efficient method possible (i.e., little back pressure).
Will they be a 12 month per year system, or just summer months. If including winter, do you plan on a backup genset?
Will the system be monitored daily or does it need to operate without anyone there (batteries run to dead a few times will not last very long), etc...
Anything to conserve power--then look at designing the solar power system to support your needs.
Powered by vBulletin® Version 4.1.10 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.