What if I don't want/need batteries in a sysyem

[Gary]

Several have pointed me here from the wind forum and it's making sense to me.  All I want to do is pump water from a stream to a storage pond, perhaps 5 gal/min or more with a lift of about 12 feet.WHEN THERE IS ENERGY AVAILABLE.  With any kind of efficiency 50 - 100 watts should be adequate if I can find a durable pump that small.  I don't care about storing power to use at night.  I guess a controller wants to see a battery to charge in addition to a load.  And of course I want the power to shut off when there is not enough power to operate a pump motor correctly so it doesn't burn up. I don't think I want the control to allow the battery to discharge down to 10.8 V every time.  Why work the battery hard if there is no need?

I suppose 120v ac pumps are easier to buy than 24v dc but I could use either.

Will any small lead acid battery make a controller work to do what I want?

What kind of controller?

Thanks,
Gary

[joestue]

you might take your chances with this guy

https://www.ebay.com/itm/DC-12V-24V-50W-Watt-Solar-Panel-Submersible-Fountain-Pool-Pond-Garden-Water-Pump/201559391457

one of the reviews for this one says I'm averaging about 7-8 gallons per minute at 12ft head on 120 watts of power.

 https://www.ebay.com/itm/DC-12V-Farm-Ranch-Solar-Powered-26-4GPM-Submersible-DC-Water-Well-Pump-23FT/122885865347

[dnix71]

Remember too that the nameplate rating on a panel isn't real life in most places. It's "tropical sun at 70F" which does not even exist except at higher altitudes.

So a 250 watt panel to run a 100 watt pump (direct DC WITHOUT a controller) is workable. You do want to add a backflow valve in the well even if the pump has one. That way you won't lose what was pumped part way up.

https://www.ebay.com/itm/1-PC-60-000UF-75V-SCREW-TERMINALS-COMPUTER-GRADE-CAPACITOR-3186GN603M075APA2/222102129548 Something like this across the panel would act as a very small battery to smooth things out in low light or passing clouds.

[Mary B]

Something like this would be better for smoothing in a pump situation, it will help with startup inrush current draw also https://www.ebay.com/itm/3-0-Farad-Digital-LED-12-Volt-Power-Capacitor-Car-Audio-Amplifier-Power-Supply/161209728867?epid=28009474911&hash=item2588d93f63:g:o18AAOxyVaBS5nqp&vxp=mtr

[Gary]

Thanks for the replies.

Wouldn't some kind controller be needed to prevent the pump from being supplied with voltage/current until the panel output is adequate to run the pump to keep the pump from burning up?

[dnix71]

The pump listed can run dry without damage. With very low voltage it just doesn't pump much or at all. A submerged pump won't warm up much anyway, as the water around it carries the heat away. You can test this yourself if you have a battery powered weed whacker. Put a few volts on it and it will just sit there. Bump up the voltage a bit and it will spin slowly. Only when you get to a certain voltage/current combo can you do useful work with it. As long as you don't lock the rotor you will have no trouble. You need to clean the intake screen at regular intervals, too, otherwise it will not pump.

[Gary]

Update:

Connected one 230w panel to the Rule pump and it pumps an impressive full stream through 80' of 1" pipe.

Just propped up with 2x4s and aimed a couple time a day.

Can't stop before I have a two axis mount that I can at least operate by hand and add a tracking control soon.

Will post gallons/ min soon.