pumping water without batteries

[Nick-2019]

I have 2 -165 watt 36 volt panels and a 24 volt brush-less submersible well pump. I would like to pump water without batteries. Any suggestion on a controller and with no batteries is there any advantage of a MPPT over the cheaper PWM. Additional information: The pump label says 16 amps - .37 Kw I have more panels I can add to system, all I want to do is pump water for irrigation when there is enough sun shining. Since the controller seems like a switch is there an advantage of the MPPT over the PWM in a no battery situation. New to solar, but thanks to William's YouTube videos and book I am starting to learn. Thanks Nick

 

[crozza]

Without using a battery you will it a difficult task to pump water consistently, or at night. A battery will be the answer
to providing consistent power to the pump. Wouldn't be a big need for a large battery so the cost will be far less.

 

[svetz]

Q: [how can I] pump water without batteries?

Easy!

Water is used to store over 90% of the energy in the U.S. today (if not the world); batteries are gaining but they have a long way to go. The way that works is you pump the water uphill when you have excess power and downhill when there is demand. It's over 80% efficient.

For continuous water flow Nick doesn't need to use water as a battery...you just need to pump the water into an elevated tank during the day when you have solar power and gravity feeds it back out at night. The tank needs to be big enough to hold all the water you'll use during the day, plus for contingencies. For example, being without power for 3 days (of course, if you don't have solar because it's raining for 3 days, you could probably capture that rain and not need to pump it).

Q: any advantage of a MPPT over the cheaper PWM
Yes, a Maximum Power Point Tracker runs the panels more efficiently.

Q: Any suggestion on a controller?
Sorry, I'm just a theory guy. But lot's of members have practical experience with a wide range of gear, so hopefully they'll chime in.

 

[Craig]

Well most SCC require batteries to work properly. But there are many solar powered water pumps out there. Im wondering if a cheap buck converter out there would do the trick for you though. It seems to me you just need something to prevent from over voltage.

 

[Craig]

How many amps will that pump draw?

 

[svetz]

Just realized I got "pump water consistently" from the other post and not yours. So, possibly you're just looking to pump water while the sun is shining.... In that case....

Known: two 165 watt 36 volt panels, 24 volt brush-less submersible well pump.
Unknown: watts required by pump to provide needed water flow to water height

Obviously the panels can supply enough voltage, but do they provide enough amps? 165 / 36 ~= 4.58 amps
Really we need to know how many watts the well pump uses.

Also, on the batteries... my post above neglected to mention something important that @crozza brought up....

No Battery: You have a total of 330W, but those panels only put out that much power if perfectly aligned at noon.
At 11 they put out 90%, at 10 they put 75%, at 9 they put out 45% (even on a solar tracker you get less power due to atmospheric absorption). The pump can only run when there is sufficient power, so if you want the pump to start at 9 AM you need roughly more than twice the solar panels the pump needs at noon.

Battery: With a properly sized battery and an MPPT you can take all the power generated throughout the day. The battery supplies the power when the light levels are low, the battery is recharged when the light levels are high. If you don't need it to run overnight this may not be a very big battery.

 

[Nick-2019]

How many amps will that pump draw?

16 amps

 

[Nick-2019]

Just realized I got "pump water consistently" from the other post and not yours. So, possibly you're just looking to pump water while the sun is shining.... In that case....

Known: two 165 watt 36 volt panels, 24 volt brush-less submersible well pump.
Unknown: watts required by pump to provide needed water flow to water height

Obviously the panels can supply enough voltage, but do they provide enough amps? 165 / 36 ~= 4.58 amps
Really we need to know how many watts the well pump uses.

Also, on the batteries... my post above neglected to mention something important that @crozza brought up....

No Battery: You have a total of 330W, but those panels only put out that much power if perfectly aligned at noon.
At 11 they put out 90%, at 10 they put 75%, at 9 they put out 45% (even on a solar tracker you get less power due to atmospheric absorption). The pump can only run when there is sufficient power, so if you want the pump to start at 9 AM you need roughly more than twice the solar panels the pump needs at noon.

Battery: With a properly sized battery and an MPPT you can take all the power generated throughout the day. The battery supplies the power when the light levels are low, the battery is recharged when the light levels are high. If you don't need it to run overnight this may not be a very big battery.

16 amps, look at my edit on origonal post for more information on proposed system. Thanks

 

[Reh3dZone]

I might be missing something, but do you need an electrical pump to run your water? Have you considered a ram pump? If you have a large tank where the volume provides enough weight to "create a flow" you could use a ram pump. I have a 500 gallon tank 1 ft off the ground running into a ram pump that waters my garden about 15 feet uphill. Consider this video and see if building your own ram pump could work.

I apologize if, I've misunderstood your needs.

 

[svetz]

Thanks for updating the OP with more information. Facts: Run a .37 kW pump without batteries, 2x 165W panels Question: How long can the panels power the pump on an average day. Theory: Without a battery/capacitor to act as a buffer, the pump can only run while the panels output more power than are are used. Panels only provide their maximum rating at solar noon. Using the chart to the right you can use the SRU as a percentage of the panels maximum. Answer: 0 hours; 2x165*.8 = 264 Watts which is less than 370 watts. Question 2: What gear should I use? Practical considerations like that need real experience, hopefully one of the other embers can help you out.

So that's no fun. Lets make it 4 panels so we can run through the math. At 4 panels it's 2x264=528 watts. As long as the panels are over 370 watts the pump should run. So, 375/528 = 71%. At 71% the sun is 45 degrees in the sky. So that's 45 degrees before solar noon plus 45 after solar noon, or 90 degrees.

The earth rotates at 15 degrees per hour, so the pump should run 90/15 = 6 hours. That assumes the panels are always tilted perpendicular to the sun (i.e., you're out there adjusting them every day) In practice probably 4 to 5 hours per day, plus without buffering for steady operation the pump will get more wear and tear.

How much longer would the pump run if I added a battery to 4 panels?
(Aside: @MrNatural22's post on batteries might interest you)

Let's assume a solar insolation of 5, so 528x5=2525 W. Which if you captured all of it via a battery could run the pump 2525 / 370 = 6.8 hours. But the round trip on a lithium might only be 90% efficient, so 6.8 x .9 = 6 hours. Since that uses the insolation map it's an average throughout the year without adjusting the panels.

With a battery, could 2 panels run it?
264x5 = 1320 watt hours. Pump takes 370 watt hours and battery 90% efficient round trip, so 1320 *.9 / 370 = 3.2 hours

 

[Rider]

I might be missing something, but do you need an electrical pump to run your water? Have you considered a ram pump? If you have a large tank where the volume provides enough weight to "create a flow" you could use a ram pump. I have a 500 gallon tank 1 ft off the ground running into a ram pump that waters my garden about 15 feet uphill. Consider this video and see if building your own ram pump could work.

Ok, I was not even remotely aware of ram pumping. This is way cool. I have a stream with 2 small waterfalls running thru my property. Wheels be turning.....

 

[Reh3dZone]

Ok, I was not even remotely aware of ram pumping. This is way cool. I have a stream with 2 small waterfalls running thru my property. Wheels be turning.....

Consider watching more of Land To House's videos for more information and all sorts of testing of different arrangements. Our creek was dry for the last 3 months due to zero rainfall, so we had to get creative. Glad to have introduced you to something new.

 

[Craig]

Ram pumps are great but also very noisy. They are also pretty cheap. Here is another alternative Though relatively expensive at 1k.
Im considering trying one of these in my off grid.

 

[Craig]

Now that we derailed his thread ........

 

[Rider]

From the OP, "I would like to pump water without batteries. ".

I'd say we were right on target!

 

[Deleted member 783]

From the OP, "I would like to pump water without batteries. ".

I'd say we were right on target!

Except that he's using a well, not a flowing body of water.

 

[MrNatural22]

Ram pump ? Very cool. Learned something new this morning
Do the happy dance.

 

[Rider]

Except that he's using a well, not a flowing body of water.

Missed that little fact..... TY!

 

[offgriddle]

I have 2 -165 watt 36 volt panels and a 24 volt brush-less submersible well pump. I would like to pump water without batteries. Any suggestion on a controller and with no batteries is there any advantage of a MPPT over the cheaper PWM. Additional information: The pump label says 16 amps - .37 Kw I have more panels I can add to system, all I want to do is pump water for irrigation when there is enough sun shining. Since the controller seems like a switch is there an advantage of the MPPT over the PWM in a no battery situation. New to solar, but thanks to William's YouTube videos and book I am starting to learn. Thanks Nick

I want to do the same thing.

 

[Deleted member 783]

I have 2 -165 watt 36 volt panels and a 24 volt brush-less submersible well pump. I would like to pump water without batteries. Any suggestion on a controller and with no batteries is there any advantage of a MPPT over the cheaper PWM. Additional information: The pump label says 16 amps - .37 Kw I have more panels I can add to system, all I want to do is pump water for irrigation when there is enough sun shining. Since the controller seems like a switch is there an advantage of the MPPT over the PWM in a no battery situation. New to solar, but thanks to William's YouTube videos and book I am starting to learn. Thanks Nick

What kind of pump is this, and what is the output?