Which 12V pump?

RybrenRybren Solar Expert Posts: 351 ✭✭
I've been luking on this site for a couple of months, trying to absorb as much as I can, but I can't seem to find what I'm looking for.

I recently purchased an off grid cottage property. There is a small 60W solar array with a marine deep-cycle battery (all from Crappy Tire for my Canadian Friends). I believe that it's a Starting/Deep Cycle battery with ~600 cca and 75Ah reserve (whatever that's supposed to mean) It's not much, but we're only there for 1 or 2 nights a week during the summer and it does allow for 12V lighting in 2 of the 3 cabins on the property. The previous owner was using a total of 3 x 50W incandescent bulbs; I have switched them out for 13W CFLs (from Rona) and added a few 5W MR16 LEDs for reading lights in the bedrooms.

I will eventually upgrade the solar system, but not this year :(

Water is currently supplied to one of the cabins via a Pitcher-style hand pump that draws water from the lake. While it works, I would like to set up a "100G water tower" to feed the cabins rather than continuing to use the hand pump. I understand that my current solar array will not support the use of a 12V pump, but I will design the new system to support one. I do have a small generator (1750W starting &1400W continuous AC, 8A @12VDC) that I was thinking of using to run the DC pump whenever I need to refill the tank. My thought is to start with the DC pump and then I won't have to replace it when I do upgrade the solar system.

My preferred location for the pump is about 75 feet from the lake and about 6 feet above the water level. I would then need to pump to the top of the water tower, which would be about 25 feet away from the pump and about 15 feet high (I don't need much water pressure).

It seems as though most people are happy with the Shurflo pumps, but to be truthful, I am totally confused as to which one to buy. I'd really appreciate your thoughts.

Thanks,

Jerry

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,212 admin
    Re: Which 12V pump?

    If you can, try to keep the pump at or below the water level--Perhaps looking at a submersible pump.

    Lifting water can create all sorts of small headaches. Small air leak on the inlet, try find that while you are not pumping water. Plugged filter to keep sand of of pump, causes pump to stop drawing water. Using plastic pipe, possible line collapse.

    These pumps can work very nicely these days without a raised tank--Just use a pump+pressure switch+pressure tank.

    Also, these pumps do not use very much power (relatively speaking). Yes, you would need a larger system than you have now, but still very "doable" with a few hundred watt array (you will want larger to power lights, cell phone chargers, laptop computer, radio, etc.).

    One question--Do you want/need a tank/cistern somewhere to store water (iced in lake in winter, fire protection, etc.)? You can use your generator + larger pump to fill the cistern once a week, and use the small DC pump to provide water/pressure for the cabin.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • RybrenRybren Solar Expert Posts: 351 ✭✭
    Re: Which 12V pump?

    Bill,

    Thanks. Still in the very rough planning stages for the upgraded solar system - it's at least a year off.

    Right now, I just need a summer-only water system for washing up - we use outhouses and currently don't need showers or water for toilets, hence a small 100G raised water tank. Do you have any suggestions or recommendations for a reliable sumbersible pump?
  • BB.BB. Super Moderators, Administrators Posts: 32,212 admin
    Re: Which 12V pump?

    No--I am a "city guy". However, our host (Northern Arizona Wind & Sun) does sell pumps and they stand behind their products--So you can take a look here and see if there is anything of interest.

    Unfortunately, good submersible pumps are not cheap (3x the cost of a standard pump?)... And if you dig a pit to near lake level, you run the risk of flooding a standard pump. If you can keep the lift "low" (5-6 foot max), you should have fewer problems.

    I will let the other guys here recommend other "good pumps".

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • RybrenRybren Solar Expert Posts: 351 ✭✭
    Re: Which 12V pump?

    Thanks Bill,

    By "lift" do you mean the suction side for a standard delivery pump? If so, then I can manage that.

    The submersibles in the link that you provided are outside my current desired price range. It looks to me like the Shurflo 2088 series pumps would do the trick, for now. The trouble is that there's a Standard, a Premium, and a Premium sealed. Does it matter much which one?
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Which 12V pump?

    Consider doing what I do. Use a shurflo submersible to fill a pressure tank. The 9300 series will pump into 60 psi (about 100' of head) drawing about 10 amps. It will pump ~3-5 gpm. By using a p-tank instead of a gravity tank, you make the system very much simpler, and much more user freindly.

    My system works great on a small battery solar system, and I have designed and built mine to work all winter through the frozen lake.

    You could also do the same thing with a non submersible surflo type pump, but you will have to locate the pump ner the water level, as it will push water fine,, but doesn't pull water very far,, so to speak. I have built both types of systems, and the advantge of the non submersible is ease of use and repair, but is rather limited in its ability to pull water. The submersible is very reliable, but has to be removed from the water to be serviced (kind of hrs through the ice I might add, but the other would be frozen solid anyway!) and is more expensive to buy, but will last years without service. Mine has been in the lake for 5 years now, winter and summer, and h worked flawlessly.

    Should if you have other questions,

    Tony
  • BB.BB. Super Moderators, Administrators Posts: 32,212 admin
    Re: Which 12V pump?

    Sorry, being incorrect with my terms (English, barely my first and only language).

    5' from water surface to pump (inlet; filters, valves, long pump runs, etc. all make drawing water more difficult too). Not the "lift" from pump to upper tank/point of use.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Which 12V pump?
    BB. wrote: »
    Sorry, being incorrect with my terms (English, barely my first and only language).

    5' from water surface to pump (inlet; filters, valves, long pump runs, etc. all make drawing water more difficult too). Not the "lift" from pump to upper tank/point of use.

    -Bill

    What makes it very confusing in English in this area is that "lift" is used to refer to the suction part, from water level up to pump, while "head" is the distance (or equivalent pressure) to which the output side can push. Unless you use a jet type pump, the maximum lift is limited by atmospheric pressure to about 25 ft., and reduced by flow resistance in the inlet pipe, just as you say. So your first idea was correct.

    The sum of the lift and head is sometimes called the Dynamic Head, just to be even more confusing.
    SMA SB 3000, old BP panels.
  • RybrenRybren Solar Expert Posts: 351 ✭✭
    Re: Which 12V pump?

    Thanks for the clarifications.

    It seems as though the consensus is to run with a pressure tank rather than a reservoir tower. My problem is that my current solar system cannot support a pump. Unless I'm missing something - which is often the case - I'd constantly have to fire up the genny to fill the tank. That, to me, would be a real PITA.

    Sorry to be so dense. Am I missing something?

    Thanks
  • BB.BB. Super Moderators, Administrators Posts: 32,212 admin
    Re: Which 12V pump?

    No, a tank will work... It just is a bit more pain. Keeping water clean/fresh, finding a high enough location to place the tank so you have enough pressure to be useful, and of course the running of the genset (do you use the genset otherwise for lights, etc. for a few hours a night?).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • vtmapsvtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Which 12V pump?
    Rybren wrote: »
    My preferred location for the pump is about 75 feet from the lake and about 6 feet above the water level. I would then need to pump to the top of the water tower, which would be about 25 feet away from the pump and about 15 feet high (I don't need much water pressure).

    I am one of the (apparently rare) forum members who prefers a gravity water tower to a pressure tank. I see one flaw in your proposed system: I think the 75 ft run between lake and pump may cause problems. The 6 ft lift is not a problem by itself, but when coupled with a 75 ft run it may be.

    As to which 12 volt pump... any of them will work. The sealed unit is a good choice for an outdoor pump where condensation is an issue.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • RybrenRybren Solar Expert Posts: 351 ✭✭
    Re: Which 12V pump?

    Bill,

    Right now, I don't use the generator - I haven't even brought it up to the camp yet (I bought it as a backup power supply for my salt-water aquarium setup) Lights are run off of my solar system, fridge and stoves are propane powered.

    vtMaps,

    For the time being, if I run the pump off of my generator, I can set it up right at the lake shore and eliminate the long suction run. Long term, I'll have to figure out a better placement and determine how best to get power to it.

    Again, thanks to all for the valuable advice.
  • 706jim706jim Solar Expert Posts: 448 ✭✭✭✭
    Re: Which 12V pump?

    I'd scrap the water tower/tank and just install a pressure tank.

    Far less hassle and less water to go rancid.
    Island cottage solar system with 2400 watts of panels, 1kw facing southeast 1kw facing southwest 400watt ancient Arco's facing south.Trace DR1524 MSW inverter, Outback Flexmax 80 MPPT charge controller 8 Trojan L16's. Insignia 11.5 cubic foot electric fridge. My 28th year.
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