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12v Water Pump

Posted:
Sat Jan 22, 2011 5:15 pm
by woytovich
I'm looking for input regarding a 12v on demand water pump for my cargo/camper. My water source will likely be 5 gallon military water cans or possibly a 10 gallon RV tank. I am planning a WFCO converter and a battery onboard so a 12v pump will do the trick I think. I'll mount the pump in a place convenient to the can storage and intended use area and run a hose down into the can(s) as needed.
This will be for ambient temperature water for the time being. I do not anticipate any water heater arrangement.
I'd like sufficient GPM for a basic field shower so I'm thinking a 2 GPM pump will do it. I do however want to keep amp consumption down to a minimum... the 2 GPM pumps seem to jump up to 4 amps (max) whereas the 1 GPM pumps are more like 1 amp (looking at Shurflo and FloJet products so far). Is 4 amps too much if/when I am running off a battery alone... and taking, for example, 2 two minute showers/day for 4-5 days? (The 12v will otherwise be used for simple interior lighting only when I'm on battery alone)
Any thoughts or experiences would be welcome.
Mark

Posted:
Sat Jan 22, 2011 8:50 pm
by Shadow Catcher
Your best bet is probably just finding and RV type water pump and you may wish to think of a bit more capacity than you think you need currently. Also remember that the water pump pressurizes the system i.e. water to water heater and tap and or shower and or...
SHURflo® Revolution would be my choice.

Posted:
Sat Jan 22, 2011 8:53 pm
by woytovich
SHURflo® Revolution = 7.5amps... am I going to be unhappy with that when running on just a battery for 4 days? (there sill be other loads during that time - some lights at night, maybe a car stereo for a bit, and a couple of O2 Cool fans)
Mark

Posted:
Sat Jan 22, 2011 10:51 pm
by mskobier
woytotvich,
Once a long time ago, I had an old motorhome. It had a 30 gallon water tank. I installed a approx. 7 amp water pump in the system thinking I needed the capacity. To make a long story short, at about three gallons per minute, my family was able to completely drain the water tank in about 10 minutes of run time. So I would think it would be important to limit your water flow by using a smaller pump.
You stated that you were going to use a 5 gallon can or 10 gallon on board water tank. With the estimated 2 minute shower twice per day, you are looking at about 8 gallons of water per day. Your stored water is not going to last very long. As for the amp draw of the pump, the estimated run time of four minutes per day, would use about .5 amp out of your battery. You will run out of water long before you could ever run down the battery.
I would recommend the smallest pump you can find. Something that delivers around 1-1.5 gallons of water per minute. The amp draw will be much less, and your water supply will last a lot longer.
The wife and I camp several times per year. For the past few years, we have been using a ZODI portable hot water shower. It is designed to fit the small green propane cylinders, but it will screw onto a manifold too. It uses four D cell batterys to run the integral pump. The wife and I can each take a nice hot shower and use no more than 5 gallons of water total. This includes washing hair too!. Now I am not saying that the ZODI is the answer to your issue. I am just saying that installing a water pump may end up costing you more than it is worth.
I am currently in the process of converting a 7X16 CT into a toy hauler. The current plan is to install a 10 gallon on board water tank. A small 1.5 gallon water pump will supply water to a single faucet in the galley area. There will also be a single hose bib type faucet so that a hose can be attached and used to feed one of the propane instant hot water heaters with shower head. The ones I have been looking at are designed to deliver about 1.5 gallons of hot water per minute. We will still have to watch our water useage. The water system will also be able to use city water when it is available. Just bypass the tank and provide water directly to the plumbing.
Anyway, that is how I am planning on doing my water system
Mitch

Posted:
Sat Jan 22, 2011 11:21 pm
by Shadow Catcher
All the pump does is supply the system pressure, it is what you do at the flow end that regulates how much you use, I have not seen a gallons per amp comparison but I would be willing to bet $$$ there is little appreciable difference between amps used to pump a set number of gallons in high vs low volume pump.
We have 14 gallons fresh water and I plan on extending that using a flex tank when needed.

Posted:
Sat Jan 22, 2011 11:22 pm
by woytovich
I think you are right about being careful with water usage. Even with a 3 GPM pump one COULD limit flow with a 1.5GPM shower head. I gotta think working the pump below its max GPM is better for the pump - maybe not. I do plan on carrying 4-5 5 gallon cans on the longer trips... and I expect to usually be able to refill if necessary.
Maybe a 1.5GPM pump is the ticket... now, to find one...
Mark

Posted:
Sat Jan 22, 2011 11:31 pm
by woytovich

Posted:
Sun Jan 23, 2011 1:10 am
by eamarquardt
We had a Shurflow on our 38'sloop. Worked great. Used a kitchen sprayer head for showers and one in the galley to rinse off dishes (washed in salt water) with fresh water. Never noticed the drain on the battery due to the short cycle time and the spray head limited flow. You can take a great Navy shower in about three gallons of water.
Go for it as that's exactly what I plan to do. Also plan to be able to suck out of 5 gallon plastic "Jerry cans" as you mention.
Cheers,
Gus

Posted:
Sun Jan 23, 2011 7:39 am
by pete42
NAVY shower
if you haven't heard of these before it means:
wetting down
soaping up
rinsing off.
lived on a submarine for a while, 2000 gallons of water 100 men you learn to conserve or stink, I don't like stinking.
ol'pete

Posted:
Sun Jan 23, 2011 10:18 am
by woytovich
That's my standard shower anyway... (except when I'm REALLY having trouble waking up)

Posted:
Sun Jan 23, 2011 5:40 pm
by Endo
What about a submersible pump. Just drop it into one of your 5 gallon jugs.
ELECTRIC WATER PUMP
Submersible 4-1/2" long x 1-1/2" diam. pump operates on 6- or 12 volt lantern battery (not included) or from vehicle's electrical system.
Drops easily into any tank with 1-1/2"opening. Uses 3/8"-diam. hose (not included). Draws 3 amps. With 36" lead.
SUBMERSIBLE PUMP CLICK HERE

Posted:
Sun Jan 23, 2011 5:51 pm
by woytovich
I like the "on demand" function of the other pumps and their run dry feature... The Coleman "shower" I have that takes D batteries has a foot switch on the battery pack... I found that inconvenient given uneven terrain. I suppose it would work fine if I hard mounted it somewhere (knee level?)
The one you pointed out isn't cheap either. For $40 more I get the "full size" electric pump... but I do like the portability of the battery submersible... stick it in a small nylon bag and you are good to go, especially with a 12v cig lighter and/or battery clamp set-up.
I was thinking to set up the Shurflo or Flojet as "portable" by mounting it in a box with hoses and power leads on external connectors. With a couple of long 12v leads and battery clamp one could be quite a ways away from the vehicle - just gotta work out wire gauge/length...

Posted:
Sun Jan 23, 2011 7:22 pm
by bdosborn
How about an exterior shower instead?
I have one and its pretty handy. I used shurflo pumps on both trailers. I've found that the amp draw doesn't really matter much because you don't ever us it long. I used the Shurflo Whisper King on the Boxcar and it works well. I used the cheapest shurflo I could find for the teardrop and it worked well too, just kind of loud.
Bruce

Posted:
Sun Jan 23, 2011 7:34 pm
by woytovich
bdosborn wrote:How about an exterior shower instead?
I have one and its pretty handy. I used shurflo pumps on both trailers.
What GPM did you use and was it enough... or too much?

Posted:
Sun Jan 23, 2011 8:06 pm
by bdosborn
The Whisper King is 2 GPM and its about right for the shower. I don't know what the low end shurflo was but it was plenty for the dish sprayer we had at the sink.
Bruce