Need help!

I have 35 acres in north florida, I have a 31 ft travel trailer that will eventually be replaced by a good sized cabin,32x24 with loft, I also have a 200ft+well that needs a pump as well as everything else...I am having a power pole installed and would like the option to use the grid or solar in case the grid is no more to guarentee i could get water no matter what ..I would like to buy a starter solar system that would power the well pump at first and that could also be upgraded to run the camper and eventually the cabin totally off grid...The camper is 12 volt and has a propane stove,furnace and water heater, so I only need to power the well pump,a LED tv
laptop,lights,changing to LEDs and radio...

My first question is do I need to buy a 12 volt pump or can i use a regular 110 volt?

Is there a package I can buy that will power a pump that is expandable?

Help, I have no clue what I am doing, so any help at all would be greatly appreciated

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need help!

    Welcome to the forum.

    You probably will want a 240 VAC pump to lift water out of a 200 foot deep well. When grid is available that's the cheapest option.
    Here's some of the others as an example (DC direct solar pumps from SunPumps): http://www.solar-electric.com/susdssusopua.html

    Setting up a solar power system for back-up is pretty expensive, especially for running a water pump. And you'd be amazed at how much power all that little stuff adds up to in a short time.

    Here are a few options available to you:

    Generators make very economical back-up power. They run even when there's no sun and can make 240 VAC easily. You can use them in conjunction with batteries & inverter (no solar panels) for "quiet power" at night. Fuel storage can be problematic, though.

    Xantrex and Outback both have battery-based grid-tie inverters that can supply emergency power when the grid is down, plus sell "surplus" solar power back to the grid when it is up. SMA has a system (expensive) which can couple its GT inverters to its battery-based Sunny Island for the same kind of performance.

    Strictly off-grid power is possible, but the over-all cost per kW hour is many times what the utility will charge. Unless you have very expensive connection costs (like having to add miles of wire and poles) it will usually be cheaper to go either with a generator or a grid-tie system.

    A good place to start is by evaluating your energy needs with some actual numbers. The use of a Kill-A-Watt meter for 120 VAC loads is very helpful. For DC loads you need to either calculate from the device's ratings (not all that dependable) or get a DC clamp-on Ammeter to see how much power is actually being drawn and multiply that by the time it is used for.
  • BB.BB. Super Moderators, Administrators Posts: 32,006 admin
    Re: Need help!

    First, it is very difficult to build and "expandable" solar PV system... There are a few components that can change battery bank voltage (charge controllers are frequently defined for 12/24/48 volt @ XX amps operation--and the higher the bank voltage, the larger array you can support).

    The problem is, usually you have to go with a higher bank voltage, so you need a new inverter. And as you add solar panels, you find that the >100 watt panels are cheaper $$/watt, but are also non-standard for Vmp (Vmp~17.5 volts for a 12 volt battery, and 2x or 4x for 24/48 volt systems). But these flexible/large controllers are ~$500-$600+ each. Not very cost effective for a small system.

    You can probably double the size of a system--but beyond that, it is almost a complete tear down/rebuild with mostly new components.

    And then you get into specific loads... Refrigerators, air conditioning (obviously), cooking, and computers/electronic entertainment are frequently the largest loads you will have to support. And pumping, while you do not use much "energy" (kWH per day), the pumps frequently have very high power demands for short periods of time--which drives battery/inverter sizing higher to support the short/peak loads.

    To give you some ideas of power usage levels... My suggestion is to look at a 100 kWH per month (9 months of the year, use a backup genset for bad weather)... That is about 3.3 kWH or 3,300 Watt*Hours per day (maximum average). It is enough for many people to have a "pretty normal" home (lights, tv, computer, fans, washer, well pump) and using propane for cooking/heating (and/or solar heating).

    You can build larger systems--but they are expensive not only to construct, but to maintain... Plan on battery replacement every 5-15 years and replacing major electronics (charge controllers, inverters, etc.) every ~10 years or so.

    And look at ~$1-$2+ per kWH for your off-grid power costs (very rough estimate of 20 year system/maintenance lifetime). That 100 kWH per month system will "cost you" around $100-$200 per month to power your very small electrical loads (I am on grid in SF Bay Area, no A/C, no heat 6+ months of the year, family of four, natural gas, using around 200-300 kWH per month).

    If you are planning on using 1,000 kWH per month (typical North American Home) or 2,000+ kWH per month (typical home in the south with A/C loads)--those are very large systems. And usually cannot compete with grid power (even if you think power prices will continue to increase--In California, our peak summer afternoon rates can be in the $0.52 per kwH for heavy power usage--still less than "going off grid" without major conservation).

    In the end, for a "cost effective" system (whether on grid or off grid)--you really need to start with conservation.

    For example, instead of putting a 1-2 HP pump 200' down your well and running it for 10-60 minutes a day into a pressure tank, you can get low power pumps (AC, DC, even AC/DC) that have low average power and low peak power (i.e., soft start). The pumps are not cheap, but they can save you a lot on your power costs (and system capital costs). Also, you can pump into a cistern, then use a simple DC (RV type) pressure pump plus small bladder tank to provide pressure for the home.

    In the end, designing for conservation and knowing/measuring your energy usage before you design/build your solar PV system will usually save you lots of aggravation and money.

    For many people, they really do not have a good idea of how much power they will need. Building a smaller PV system and using a fuel efficient genset (Honda eu2000i is great for smaller homes/systems) as a backup/assist until you have a better handle on your loads may be a good place to start.

    If you are interested, here is a thread with lots of links/information to conservation (and solar) ideas, projects, and information.

    Working Thread for Solar Beginner Post/FAQ

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • bsolarbsolar Solar Expert Posts: 103 ✭✭✭
    Re: Need help!

    .. i put my well on solar here near gainesville. My advice is treat that as sort of a seperate issue if you want it on solar .. get its own pump with its own panels and batteries .. its own storage/holding tank. Once you have the water in the holding tank you can do about anything with it with a cheap 12v/110 volt rv pump or whatever ..

    .. the system i used was the brand 'simple pump' . it wont be a cheap thing but its quality. With the pump, tank, solar motor drive, a couple of good sized panels and a couple of batteries you'll easily have 3 grand in it. Anything else you want to do solar can be an entirely seperate system if you do it that way or you can integrate the panels into a larger array via switch so the panels serve both systems which is how mine is .. the water runs off 12v though and i dont even have to fire up the inverters if i dont want to ..
  • tmarchtmarch Solar Expert Posts: 143 ✭✭
    Re: Need help!
    bsolar wrote: »
    .. i put my well on solar here near gainesville. My advice is treat that as sort of a seperate issue if you want it on solar .. get its own pump with its own panels and batteries .. its own storage/holding tank. Once you have the water in the holding tank you can do about anything with it with a cheap 12v/110 volt rv pump or whatever ..

    .. the system i used was the brand 'simple pump' . it wont be a cheap thing but its quality. With the pump, tank, solar motor drive, a couple of good sized panels and a couple of batteries you'll easily have 3 grand in it. Anything else you want to do solar can be an entirely seperate system if you do it that way or you can integrate the panels into a larger array via switch so the panels serve both systems which is how mine is .. the water runs off 12v though and i dont even have to fire up the inverters if i dont want to ..

    I basically agree, except the battery part. If I was doing it I would simply add enough storage to the cistern tank or whatever and forget the batteries. Keep the pump on a seperate system because life without water is NOT fun. With a simple generator interface you can assure yourself of water, but it's cheaper to buy storage than fuel for a generator.
  • ggunnggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: Need help!
    tmarch wrote: »
    I basically agree, except the battery part. If I was doing it I would simply add enough storage to the cistern tank or whatever and forget the batteries. Keep the pump on a seperate system because life without water is NOT fun. With a simple generator interface you can assure yourself of water, but it's cheaper to buy storage than fuel for a generator.
    That could work with a DC pump that runs when the sun shines and a float switch to shut off the PV should the tank become full.
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