Thinking of a solar back up for well pump

RNeumann · May 9, 2017

The "picture" of what you are doing isn't very clear to me. You mentioned a tank. The typical setup is to pump from the well to the tank and if you don't have gravity from the tank to the domestic supply (house etc). With a tank all you need is enough power to run the pump from the tank to the house. Right?

I'm also totally confused why you would add a second system after installing solar and the Tesla battery system. I'm wondering what exactly the installers are doing- it sounds as if they are over complicating things or trying to up sell you. Your well, shop and house all should be fed by your top of the line system. Wires go in between all these locations from the grid so why wouldn't they also work from the solar/Tesla system? This would negate the need for a second solar/battery system.

I'm not trying avoid answering the question. But it appears as though you may be over complicating things. To your question about having done this. The answer is yes. But the variables are way beyond the information provided thus far.

Hopefully your answers will provide some clarity for me and we can get you pointed in the right direction. No hand pumps allowed!

JK22 · May 10, 2017

handirifle said:
just don't want to have to turn on a generator to wash my hands, or leave it running all day. That is the negative of a generator, it is not demand friendly.

I have no desire to walk 30 yards up a hill, in the middle of the night so I can flush a toilet.

If you are researching alternatives, plenty of remote start generators out there.

handirifle · May 10, 2017

Well hopefully I can make it clear. The well is 560+ ft from the 5400 gal storage/fire tank. It (the tank and booster pump system) IS slightly above the house, about 8ft is all. So we do get SOME gravity feed, but only about 4 psi. It will SLOWLY refill the toilet tank, but that's about all.

Yes I just need to provide enough pressure to shower (40+ psi). There is an air bladder pressure tank at the storage tank location, in fact EVERYTHING is located there. The site surveyor for the solar company mentioned something about tying them together, but I do not know enough about grid systems to know how they would do it. We have my shop, our spa, the well system and our RV pedestal on one meter, and the house alone on the second meter.

I will NOT go to a single meter system, because we get much better rates with the dual. The well one rarely ever goes above min baseline fee.

The solar system is primarily for the house, as I am not sure the Tesla battery would provide enough reserve for the house appliances AND the well system. By my calculations it's about 583ah at 12v, but I might be off.

I might be able to get by with a 1/4hp 110v pump, just not sure on that one. Have not researched those to see how they would flow at 40+ psi.

Hope I answered your questions.

RNeumann · May 10, 2017

Ok a typical house of 2 uses about 100 gal a day without any conservation. With conservation you can get that way down. Say 25 gal a day. At that rate you would have about 8 months of storage water and therefore no need to run the well pump.
Because you do have some gravity between the tank and house a LITTLE booster pump would work fine. Think the one in your RV. Plumb the thing in before the pressure tank on the storage tank side and the other side would be at the house. All you would need to do is flip a switch to turn the 12v pump on. If you were really not wanting to leave the house a remote switch would be in order- like a garage door opener.
To power the 12v pump I'd have the same setup as an RV- 2 6v deep cycle batts and a 12v panel big enough to take the batts from 75% of rated capacity to full charge in a day. The typical sun where we are at is about 9 hours a day and the panel capacity should be derated to about 60% (clouds, angle to the sun etc).

If it was me I'd run a conduit between the house and well. I won't go into the two meters- I get it. But anything you are talking about adds cost, maintenance and complexity. Once the conduit is in it's done. All you would need to do is throw a switch (or it could be automatic) and the booster pump would run off the house.
Your hypothetical of the Tesla not being able to run the house and well is misguided. It's making the assumption you won't have sun to power panels. If that's the case the well lash up you are thinking of wouldn't work either- its solar as well......

If you don't like the options above we can continue. The cost etc will be going up quickly though.

jenkinsph · May 10, 2017

RNeumann said:
Ok a typical house of 2 uses about 100 gal a day without any conservation. With conservation you can get that way down. Say 25 gal a day. At that rate you would have about 8 months of storage water and therefore no need to run the well pump.
Because you do have some gravity between the tank and house a LITTLE booster pump would work fine. Think the one in your RV. Plumb the thing in before the pressure tank on the storage tank side and the other side would be at the house. All you would need to do is flip a switch to turn the 12v pump on. If you were really not wanting to leave the house a remote switch would be in order- like a garage door opener.
To power the 12v pump I'd have the same setup as an RV- 2 6v deep cycle batts and a 12v panel big enough to take the batts from 75% of rated capacity to full charge in a day. The typical sun where we are at is about 9 hours a day and the panel capacity should be derated to about 60% (clouds, angle to the sun etc).

If it was me I'd run a conduit between the house and well. I won't go into the two meters- I get it. But anything you are talking about adds cost, maintenance and complexity. Once the conduit is in it's done. All you would need to do is throw a switch (or it could be automatic) and the booster pump would run off the house.
Your hypothetical of the Tesla not being able to run the house and well is misguided. It's making the assumption you won't have sun to power panels. If that's the case the well lash up you are thinking of wouldn't work either- its solar as well......

If you don't like the options above we can continue. The cost etc will be going up quickly though.

That is pretty much the same thing I suggested at the start of this thread. A simple rv pump, battery or batteries and small charger. Adding a cheap timer that is set to run the charger during daytime hours when the solar panels are working would do the trick. This could be located at the house and be fed by the gravity line with 4 psi no problem. Bypass valves for normal operation would need to be turned at the beginning and end of the power outage but that is still simple enough to do. This should be good for 100 gallons per day. I agree with more conservation and lower usage though, I could get by with a lot less while staying clean and having water for other needed uses.

RNeumann · May 10, 2017

jenkinsph said:
That is pretty much the same thing I suggested at the start of this thread. A simple rv pump, battery or batteries and small charger. Adding a cheap timer that is set to run the charger during daytime hours when the solar panels are working would do the trick. This could be located at the house and be fed by the gravity line with 4 psi no problem. Bypass valves for normal operation would need to be turned at the beginning and end of the power outage but that is still simple enough to do. This should be good for 100 gallons per day. I agree with more conservation and lower usage though, I could get by with a lot less while staying clean and having water for other needed uses.

Yep the RV ones even have a built in pressure switch so they only run as needed/on demand. This is the easiest and most cost effective. Plus the design saves water.
Their is no need to store more water- just access the water in his existing tank.

I'm not 100% that manual valves would be needed. Check valves on the two pumps would prevent the water from "looping" back through the pump that isn't running. The main pump should have a check valve already- between the booster pump and the pressure tank. You could also add a check valve on the other side of the pressure tank to prevent the 12v pump from refilling the pressure tank.

handirifle · May 10, 2017

Well sounds like some reconsideration on my part is in order. Sorry for sounding obstinate, I get single minded once I fet an idea and I have to be convinced (by myself or others) that it won't work.

Good point about check valves. Honestly never thought of that one. Would not have been too happy to run the pump and get no pressure from it

.

I would have a concern about reliability of the RV pump. I know from experience they are not as durable as a standard unit. The simplicity is inviting.

Lol what I meant about not wanting to go up there was every time I needed to start a generator as opposed to running it constantly. No problem doing it for the switch over.

RNeumann · May 10, 2017

To run the 240v pump requires the inverter (as you know). Inverters are only about 80% efficient so you lose a lot of battery and solar there. Then throw in the number of batteries needed to make a voltage that can be "inverted" to 240v. I'm assuming 120v or 20 6v batteries. Then you need the panels to keep the 20 batteries charged and recharged. Throw in the difference in watts. A booster pump is something like 15a at 240v or 3600w. As a comparison the 12v pump draws maybe 10a at 12v or 120w. The larger pump requires 30x the power which equates to 30x the solar and batteries!!!!!!! EXPENSIVE!
The other issue is the 240v booster will use more water.
With the money saved buy 3 of those RV pumps. And buy Jenkins a beer!

The Tesla battery is something like 480v which helps a lot. Stepping the voltage down is much easier and a few golf loss doesn't amount to much. That is why that technology is so different.

I'm still hung up on getting power from the house to the well or shop or RV so the other "system" can be back fed by the Tesla.

handirifle · May 10, 2017

The "back feeding" idea is a good one and I will approach them with it. My only problem might be from where. I will look into that. In the meantime I have come across the Backwoods Solar site and am investigating the 12-24v DC idea as well. Your input has been helpful, as well as other thoughtful ideas on this thread. The most economical would the the "back feed" I am sure.