An Awesome Off Grid Water Pump From Off the Shelf Parts

For those times when water really does need to run uphill, the Redneck Genius Factory presents an Awesome Off Grid Water Pump from Off the Shelf Parts.

1. A 900 GPH Breckett pump with included prefilters from Home Depot ($79) .

2. A 12 volt four wheeler or motorcycle style battery from Walmart ($29)

3. A 400 Watt car inverter from Walmart ($29) - you can use a smaller inverter

4. 25 foot 5/8" medium use hose from Home Depot ($16)

5. Paracord or similar "string" from Walmart ($3)

6. 1 stainless steel pipe clamp that closes to less than 1" diameter from Home Depot($1)

7. A big plastic water tight-ish box from Home Depot ($8)

8. An extension cord from Home Depot ($10)

9. Satisfaction at a job well soaked in a backwoods hot tub in the middle of nowhere in the southern Appalachians? PRICELESS

Step 1: Step 1: the Right Pump for the Job and the Right Hose for the Pump

First off, you need a pump, because if you could open a worm hole to move your water across space time you would not need this instructable to begin with! Home Depot or Lowes carry a selection of pond pumps off the shelf. You want one that works with prefilters if you are working off grid or with dirty water to remove sediment that will over time accumulate in your hoses/pvc pipe and damage your pump. If you are pumping uphill, you need a WATERFALL pump. Not a fountain or regular pond circulating pump as these generally cannot lift water very high. Next, look at how many feet the label says you can lift that water. This one says 12.8 ft. This is 12.8 ft vertical. If you are running diagonal up a hill side (such as the side of the mountain) multiply this distance by 2. So this particular pump, on paper, can push water up hill at a diagonal angle about 25 ft.

This sounds great, until you realize that these large pumps use large tubing. This one, if you flip it over, says it uses 1" tubing. This will be very expensive and hard to get as vinyl tubing that is UV protected for outdoor use. So you could get 1" PVC pipe, which is dirt cheap. However, that would require permanent installation and burying the pipe to avoid freeze fracturing of the PVC or eventual UV degradation of the PVC. Assuming you are even in a situation where it is reasonable to dig a 1ft deep trench to accommodate your PVC or that you want to. In short, screw that.

These pumps can use small diameter tubing, but doing so increases the friction action on the water column as the pump tries to push it up hill. This will decrease how far the pump can push the water, and if you try to push it too far no water is going to come out of your hose! A reasonable rule of thumb by trial and error is if the pump can lift water 25ft on the diagonal, if you drop the pipe size to 1/2 of what the packaging tells you to use plan on it being able to pump 2/3rds of that 25 ft distance on the diagonal, or 17 ft. The straighter the hose the farther the pump can send the water too, so try to avoid snaking your hose out through the weeds!

If you multiply 1" by 1/ get 1/2in. Which is great, because that's the size range of your average freeze proof easy carry garden hose, and wallah, Lowes or Home Depot carry plenty of those in a range of prices to suit all budgets! Go select one long enough to run from your water source to your water destination, but avoid buying the cheapest as you will have to heat fit your hose to the pump. Buy 2 pipe clamps (plumbing aisle) that will tighten down to less than 1" diameter. The distance the pipe clamp will open or tighten is written on the front of the box. Buy 2 because while you only need 1, if you accidentally bend, back out, or just plain get one that doesn't seem to work quite right you don't have to drive 20 minutes back to home depot in the Jeep up the rutted deer trail to get another 97 cent part. Your time is worth more than 97 cents.

Step 2: Selecting a Battery for Power

On your way home from Lowes stop at Walmart. Cruise on over to the auto parts section for your power supply (read: four wheeler battery) and you DC to AC inverter (read: car plug inverter). For this particular project you will need to match your battery and inverter to what your pump needs to run. Time for some very important math!

1. I have a pump. On the outside of the pump's box it says 75 Watts.

2. I have found a battery for a four wheeler. On the outside of it (see image) it says 12 volts and 10 Ah. Ah means "amp hours".

3. Realize that there is nothing about Watts on this battery, so how do you compare what the battery provides to what the pump needs? You must convert the battery supply to the same units as the pump.

Watts = Volts*Amps

Watt*hour = Volts*Amps*hour

Watt*hour = 12 volts *10 Ah*1 hour

Watt*hour = 120 Watt*1hour

Your pump pulls 75 watts to run, therefore:

120 Watt*1hour/75Watt = 1.6 hour run time

4. Is this enough time? This pump says it will pump 900 GPH (gallons per hour). Now, this is probably an outright lie, or more kindly, a gentle fib based on what it should pump on paper. It's probably more like 750gal, especially considering we are using a smaller hose that recommended. But what job exactly do you have that you need 750*1.6hr = 1200 gal of water for in an off grid situation anyway ?! This should be plenty for most situations such as filling a trough, a storage tank, or irrigating a small garden. IMPORTANT: you cannot completely drain a battery - plan on getting less than a 1.6 hr run time, maybe more like a 1.3 hr run time.

Step 3: Choosing an Inverter

While you're cruising the local Wally World's automotive section with your new battery in tow, take a trip to the car inverters. Pick you out one you like the color of and has at least as many watts printed on it as your pump will draw. This inverter pictured is a 400 watt inverter, more than ample for a 75 watt pump. The inverter will convert the DC power supplied by your battery to AC power that your pump will run on. Make sure it has alligator clips to attach it to the battery. If it does not, in the same section your should find a connector that will attach to the cigarette lighter plug and provide you with alligator clips. Alternatively, you can splice them onto the plug.

***IMPORTANT: Most car inverters do not have reverse polarity protection. What this means is, if you put the alligator clips on the battery backwards, i.e. the negative on the positive and the positive on the negative, you will DESTROY your inverter. Be careful!***

Step 4: Choosing Housing for Your Battery and Inverter

Buy something cheap and plastic from the Wally World home goods section. A water tight box is great, but remember to drill a few holes in the side above where water might easily get in to allow the battery to vent when it is being discharged. Oh, and make sure the &#*@ thing easy to carry.

Step 5: Get the Hose on and the Pump in Place

In my case I am running water from a large spring fed storage tank up hill to fill an off grid hot tub. Yes, I know, decadent, lazy, not actually crucial and all that...But you know you've dreamed about it when you're sweaty in the woods. Any reasonably large source of water that won't be depleted so fast the pump ends up running while not completely submerged in water will work.

Attach the hose by first cutting off the female end of the hose (the one that would usually go on a spigot). Using a fire, hand held torch, or a lighter, heat the end of your hose until it is warm enough to go around the opening of the pump. You may need to make a small notch in the hose to get it on. Attach your pipe clamp to hold it onto the pump.

Next, get some clean string or rope and tie it around the pump. This is to help you fish your pump out of the watery depths for repair and to suspend the pump in the tank so it isn't sitting in any silt that might have accumulated on the bottom of the tank. Again, silt is the enemy of pumps, water lines, and clean hot tubing water! It is ideal that the string support the weight of the pump, not the hose or the power cord. If you cannot suspend the pump via the string, still have a string to retrieve the pump if necessary, but put a rock or concrete paver into the water body for the pump to sit on out of the silt instead.

Run the hose in as much of a straight line as you can from your water source to were you need the water to be, then get your battery and inverter in position.

Step 6: Hook Up the Battery, Inverter, and Pump

Clip your battery to your inverter, (IMPORTANT: do not hook the positive to negative and negative to positive. This reverse polarity will toast your inverter! I have done it!). Plug in your submerged pump, and let the water flow!



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    2 Discussions


    20 days ago

    Knowing a bit about batteries you are not going to do very well with that battery . Lead acid batteries should not be discharged beyond 50% . To do so will drop the number of times you can discharge /charge to maybe 100 before the capacity of the battery has dropped to useless. Getting to 50% more quickly and taking it lower each cycle.

    It will work OK for 10 times maybe and you will notice it failing from there. You need at least a 25Ah for that and I would go for 50Ah. If you are serious look at getting a 12V Lithium Iron Phosphate battery of 100Ah (they come in their own dropin style these days see Amazon) with a good solar panel charge system . One cheap house panel of 250 watts would keep it topped up nicely and it will last 10 years or more and enable a pump upgrade too.

    Join this site and get much more knowledge on LFP batteries


    20 days ago

    Thanks for sharing this storage and pump system! Looks awesome!