Cabin Water System (looking for design help)

[elkhunter1]

Hi, I am new to this forum. Been surfing it and really like it.
I have a small off-grid cabin that I heat by wood with a propane heater as a secondary source (only comes on when we are using the cabin and are away for a day or so-just to keep everything from freezing. The cabin is located in a very cold area of the US and as such, freezing issues are my primary concern. The cabin is used only intermittently and has to be winterized after each use. I had a hand pump in the kitchen area that was supplied by a hand driven sandpoint well. I want to get away from the handpump and am having a 6" well drilled. It will only be 25' deep. I am going to be installing a small PV solar system, but am running into design issues with my water supply system.

Due to the cold weather and freezing issues with my water supply, I am envisioning a small, 40-50 gallon water storage tank in the attic, which will enable me to drain the system by gravity. I will be able to provide heat via vents to the attic which I will close in and insulate where the water tank will be.

I want to fill the water tank from a 12v submersible pump with a water level switch (shuts water supply off once full). The outlet side to fixtures will then be pressurized via a 12v RV type water pump, supplying water to a tankless water heater, a bathroom sink, a toilet, a shower, and a kitchen sink. I am looking to set this up as a day tank type scenario, with me, but using a switch, energizing the well pump in during daylight hours to fill the day tank, but it being semi-automatic during the day, refilling the day tank as necessary automatically. I also want to have the ability to turn the pump on in the evening hours, should I use all the water in the day tank.

I am looking for suggestions on the supply side. 12v well pump (make-model, etc.); water level switch (make-model, etc); timer switch with over-ride in the event I need to fill at night from the battery system? Am I making this too difficult? Design help?
Thanks a bunch and I look forward to surfing the site more for PV/battery/power converter system requirements for this cabin.

[Mike90250]

What do you do for lighting and other power needs - or will this be your only power need ?

I ask, because if you have modest needs, everything may run off a 300w sure sine inverter (morningstar, 600w surge for 10 min) and using 120VAC opens up a lot of timer and control options.

Also, 12V submersible pumps are not likely to be able to provide 30' of lift (water table to attic tank) AND 30+ psi to pressurize the tank (or maybe this is only a storage tank, not a pressure tank ?)

[elkhunter1]

What do you do for lighting and other power needs - or will this be your only power need ?

I ask, because if you have modest needs, everything may run off a 300w sure sine inverter (morningstar, 600w surge for 10 min) and using 120VAC opens up a lot of timer and control options.

Also, 12V submersible pumps are not likely to be able to provide 30' of lift (water table to attic tank) AND 30+ psi to pressurize the tank (or maybe this is only a storage tank, not a pressure tank ?)

Mike,
I plan on running a 1000 watt Morningstar PSW inverter to power the residence on AC. I plan on using CFL/LED lighting and all appliances will be propane. I have an energy budget of 1500 watts daily, including system loss (really closer to 1200 watts daily). I plan on 3 250 watt PV panels supplying a battery bank with appr. 9600 watt hours of 12v.

I want a small day tank in the attic (approx. 50 gallons) as I don't have a lot of room and I will have to build a containment system in case of leaks.
Attached is the link to the DC well pump. http://www.sawtechnology.com/WaterPump-P.html I am looking at the 70 watt with 29 ft head pump. That will not be a pressure tank. Then I will pressurize the supply side with a 12 volt RV type pump.

I know it seems odd to have a 12v system and a 120v system sidexside, but with the energy budget (I want a 4 day supply of battery power in the event of bad wx) I think this is the way to go, but I am brand new at this and I am looking for answers before I commit to any particular system.

By the way, I will have a 25' run from the DC breaker to the well pump, so it will not result in tremendous line loss.

Any suggestions?
Thanks,
Jim

[lerryvon]

Nice Plan

I think containment system is very space consuming as well as it will take more time so it should be avoided.

[FloridaSun]

I think containment system is very space consuming as well as it will take more time so it should be avoided.

Wrong lerryvon.. A pan under 50 gallon tank w/drain to outside could save a big mess from happening if a pipe burst in his climate.
Elkhunter has the right idea

[liderbug]

Question, is there a stream/creek/raging river... nearby? If so you could run poly, providing there is enough drop, to the cabin and a turbine/generator. That way you could always have dhmo and power.

25c

Chuck

[elkhunter1]

Design Change and Seeking Input

Ok, glad I am open to other ideas. I am pretty handy with DIY, but I am in uncharted waters for me. What do the pros/people with experience think of the following?

I queried Bruce at http://nemosolar.com/dcsubmersiblepumps/index.html about his Nemo pumps. They can be run on either 12v DC or 115v AC. I have 1000 watt inverter so either works for me. My wiring run will be less than 60 feet from the breaker box to the bottom of the well casing and in reality will be likely about 45 feet.
If I can eliminate the non-pressurized storage tank and a second 12v pressure pump, it makes the system much simpler.
I am thinking of using the Nemo pump to provide water to a couple of smaller pressure tanks connected in series that will be in the attic. I am pasting the question and response from Bruce at Nemo that I asked. Anybody see problems with this? Reliability issues? 12v DC or 115v AC-this is the big question-what do you guys recommend? Issues related to pressure switches if I go the 12v DC route? Any/all input is sought.

Hi Bruce. I have an off-grid cabin with a PV/Battery system and a 1000 watt inverter and I want to run a 12 volt submersible well pump to supply household water. The well is 25' deep and I have a 20' lift to where I will be storing water. I have a few questions and hopefully you can answer them:
Will the Nemo V2 supply enough pressure to fill a pressure tank (2 20 gallon pressure tanks connected in series due to space limitations)?
With the above describe head, what will be my electrical usage be in watts? Again, but with 120 volt AC powering the pump?

Bruce's Reply to me: Dividing the total vertical distance between the pump and the tank by 2.31 gives the PSI required to lift the water to the tank (let's say about 40 feet divided by 2.31 = about 18 PSI). To that figure you need to add the PSI cut-out setting on the pressure switch at the pressure tank ( let's say 18 + 40 = 58 PSI), which is the total system pressure required for the described system. So yes, being that the Nemo V2 pumps are rated at a maximum 100 PSI, the calculated 58 PSI is well within the capacity of the pump to fill your tanks.

With a 12 volt pump operating at the calculated 58 PSI, the continuous power draw would be about 66 watts (not counting some momentary start up surge when under load).

The performance characteristics of the Nemo AC pump is virtually the same as the Nemo DC pumps, but the AC pump can use lighter gauge wire, which is a cost advantage for long wire runs. The wattage would be slightly more to allow for the DC to AC conversion factor of the inverter, but quite negligible given the low overall demand of the pump (even at a maximum 230 foot lift, a Nemo AC pump will be amply supplied with a small 200 watt inverter).

[Wy_White_Wolf]

Shurflow 9300 should work. It can be run with a LCB (linear current booster) that allows the use of a tank float switch and can have a bypass switch installed to run from battery when desired.

http://www.sustainablepreparedness.c...ble-water-pump.

Have you checked out the water pumping links at http://www.builditsolar.com/Projects...terpumping.htm

WWW

[elkhunter1]

Recoomendations

WyWhiteWolf,
I ahve looked at those sites. Thanks. I am thinking that I will install a LCB and a magnetic switch. I think this is the simplest system I can come up with and still have a easy to winterize system. Thanks,
Jim

[myskylander]

Thanks

Thank for sharing