Pumps

I have a 12 V ..20 watt solar panel running a 12 v 15 watt fish pond pump ,I want to connect a battery between the two for continues running ,what would be the best size battery (amps ) and what sort of charge controller would be best ,thanks
firstly thanks for your imputs so far
when I say"continues running " I was meaning during periods of cloud through out the day instead of the stop start that happens at the moment
when it’s a very cloudy day then I don’t expect the pump to run but I want to make sure it doesn’t run the battery too low

If you are running the 15W pump continuously, the 20W solar panel won’t be big enough. 15W x 24 hours = 360 watt hours (wh). Since the solar panel is generating electricity only during sunny hours, it can’t keep up. Let’s use 5 sun hours as an example, which is the total number of hours the sunlight is equal to the standard test rated power. 20W x 5 hours = 100wh. You’re 260wh short. You need around 95W to do what you want. (360wh / 5 sun hours + ~30% inefficiencies) http://www.altestore.com/store/Solar-Panels/100-to-149-Watts-Solar-Panels/Carmanah-CTI-110-110W-12V-Solar-Panels/p6871/

For the battery, you’ll need a deep cycle battery that is designed to be drawn down to about half way and recharged, repeatedly. They are rated in amp hours, (ah), not cca. Since you only can use half the power in it, you need it twice as big as you calculate. If you need 360wh, that’s 30ah usable power, 360wh / 12v = 30ah. 30ah x 2 (only using half of battery) + 15% (battery losses) x 1.19 (50F temperature compensation)= 82ah battery. http://www.altestore.com/store/Deep-Cycle-Batteries/Batteries-Sealed-Agm/Universal-Ub12900-12V-90Ah-20Hr-Sealed-Agm-Batt/p2004/

The charge controller is rated based on the current output of the solar panel. That 110W 12V panel is rated at 7.5A. Add 25% safety margin, you need at least a 9.3A charge controller. If you get one with a low voltage disconnect (LVD), you can have the pump automatically shut down if the battery gets low, saving the life of the battery if you’ve had a day or two of clouds or rain. http://www.altestore.com/store/Charge-Controllers/Solar-Charge-Controllers/PWM-Type-Solar-Charge-Controllers/Morningstar-Charge-Controllers-PWM/Morningstar-Sunsaver-Ss-10L-10A-12V-Pwm-Chgctrl-Lvd/p799/

You can run the numbers through a calculator like this to see for yourself, http://www.altestore.com/store/calculators/off_grid_calculator/

…….Update based on asker’s update…………. If you just want to run it for as long as you can with your 20W solar panel, you can size it based on your potential output from the solar. Let’s say 1.3A output, 5 sun hours, so 6.5ah. Multiply by 2 since we’re only using half of the battery, so at least a 13ah battery, figuring you’ll be using the power about as fast as it’ll be putting into the battery, so it’s really just acting like a buffer. I suggest rounding up if possible, since I didn’t figure in any inefficiencies or losses. http://www.altestore.com/store/Deep-Cycle-Batteries/Batteries-Sealed-Agm/MK-ES17-12-18-Ah-Sealed-Lead-Acid/p5925/ . Or if budget is more important than running duration, then http://www.altestore.com/store/Deep-Cycle-Batteries/Batteries-Sealed-Agm/Universal-UB12120-12V-12AH-20HR-Sealed-AGM/p1996/.

I still recommend a charge controller with a LVD to turn the pump off when the battery is low. So, while the panel requires only about a 2A charge controller, the smallest charge controller I can think of with LVD is the 6A, http://www.altestore.com/store/Charge-Controllers/Solar-Charge-Controllers/PWM-Type-Solar-Charge-Controllers/Morningstar-Charge-Controllers-PWM/Morningstar-Sunsaver-Ss-6L-6A-12V-Pwm-Chg-Cntrl-Lvd/p804/.

Monday morning my plumber is coming out and look at my septic Tank Pump to see if it’s a bad switch or I need a whole new pump. 10 yrs. ago I bought from him my Goulds Pump and he installed it. Should my pump have lasted longer then that or is that about right. I have a 900 gallon tank and one person who lives in the house ie,, sometimes 2 when my girlfriend comes over and showers and uses water. The problem is my tank is overflowing. Thanks.

10 yrs from a sewage ejection pump is pretty good. I have seen them last as long as 15-20 yrs., but that is rare. I’ve found the life to be around 7-10 yrs.
The amount of use of the pump isn’t determined by the size of the tank but by the actual float setting.The travel of the float up and down determines how often the pump runs.
Good luck.

here is a picture of one the same,

http://www.prestonservices.co.uk/USA_SteamPump.jpg

i have searched EVERYWHERE and can not find anything.

Google…

If you are looking for technical (spare/repair) info I would think that steam (trains) enthusiasts will be able to help

The present pressure pump is 15 years old. We also have sulfur in our water.

the pipe to the home might be clogged a pump with more horsepower a bigger airator

My QBs are Michael Vick, Brett Favre. and Eli Manning
i know it’s between Eli and Brett but Eli just got that contract and should be pumped
heres the rest of my tream
AND I AM NOT GETTING RID OF VICK!!
RBs: Adrian Peterson, Matt Forte, Thomas Jones
WRs: Steve Smith, Calvin Johnson, Benard Berrian, Devin Hester, Terrel Owens and Donald Driver
TE is Jeremy Shocky
K is Robbie Gould
and my D is New England

Since you dont have a clear starter qb, i would play the situational qb game. I would play whatever QB has the weakest defence(or pass defence) that week… not that i am high on favre, but 4 out of his first 5 weeks he does play Detroit, Cleveland, St.louis, and Sanfran. I see no reason why favre wont have multi TDs on those days.

The main question that you should be asking is, How would the idiots in my league let me draft AP and Forte?
6 team league?

What will be theoretical approach to calculate pressure at output of propeller block if pump motor is rotating at speed N rpm? like using maths and probably integration?what will be theory?

A pump does not create pressure, only flow, which is used to calculate resulting pressure from input power and output aperture cross section.

Power delivered to the pump is
P = 2 pi N T
N = Revs/sec
T = Torque in Newtons
P = Watts

Power delivered to the fluid is the volume flow times the pressure drop
P = (m^3/second) (Pa) = (m^3/sec)(N/m^2)
Pa = P/(volume flow)

http://www.eng.utoledo.edu/polymer/info/Courses/LabIHandouts/Pump%20Characteristics.pdf
http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&channel=s&q=Using+RPM+to+calculate+pressure+at+pump+outlet&btnG=Search&aq=f&aqi=&aql=&oq=

.

I have a cover over my pool outside, and during the off-season it often gets a large amount of rain water that accumulates in the middle of the cover several inches or more deep. Can anyone recommend a really good, small, reasonable electric submersible pump I can buy that I can plug in outside and toss the pump down in the "pond" of water & pump it off fairly quickly? I am sure nowdays some companies make some nice little portable pumps that are waterproof & submersible.
Thanks for any recommendations you can give me !!
Thx TC & Oil Field, good suggestions - Human-guy, no can do what you say, to start with its round/oval, not square - there are no "sides" - also the pool is 15 x 30, I don’t know if you realize how large that is but there is no way you can pull that huge of a cover tight enough so there is no ponding of water on top, u obviously have no experience w/ this situation.

I wish I could remember the one I used in Arizona for exactly that purpose …..I think it was “little giant”….but I can’t remember …been a few years.
I had a retractable cover and would throw the pump in the middle {it had a garden hose attached to it} and pump it out…….. here is a site you can check.
Little giant is also readily available at Ace I think …Home Depot
http://www.justwaterpumps.com/asp/superbrowse.asp?clid=921&caid=&sku=LGP1270&refid=GANk232270