Dankoff Slow Pump Ugrade Suggestions?

[shaniac]

Hello. I have a dankoff slow pump (110V) that is coming up to the end if it's 20 year suggested life span. It has been a heck of a trooper so far with nothing needing replacement but normal brush wear and occasionally the diode block.

 I push the water up about 200 feet, across about 850 feet of 1 inch pipe. The 110 comes from a typical solar / inverter solution (on top of the ridge) and I push the power down via 850 feet of 10/2 to where the slow pump is on our North slope.

 As you can imagine I don't get that many GPMs,(as that is the nature of a slow pump...) but it has worked well with water storage and conservation over the years.  Since the system is getting old, I am looking at upgrading to a better solution (perhaps a few more GPM?.) Does anyone have any suggestions that works well for them?

 Perhaps two slow pumps pushing up through the same 1 inch pipe? Or perhaps there is something better on the market? I am open to any ideas and my upgrade would start taking place in September. I have plenty of solar power on the top of the hill. The issue is always how to get it down where it needs to be. Thank you in advance folks for all your wisdom over the years.

[shaniac]

Hello folks, looks like many people have read the post but no comments yet? Hopefully we will hear something soon. Right now I am researching the how the different pump head types effect flow. Thank you again!

[Frank S]

Interesting data on those pumps

Technical data Dankoff Solar Slowpump
Total Lift   1322   1310   1308   1304   1303   2505   2507
Feet   Meters   GPM   Watts   GPM   Watts   GPM   Watts   GPM   Watts   GPM   Watts   GPM   Watts   GPM   Watts
20   6   0.51   27   0.92   29   1.25   30   1.75   37   2.50   48   3.25   55   4.00   57
40   12   0.51   32   0.92   41   1.25   48   1.75   53   2.50   60   3.23   69   3.95   78
60   18   0.51   36   0.89   46   1.20   54   1.68   64   2.40   78   3.15   90   3.90   102
80   24   0.49   40   0.88   51   1.20   60   1.64   73   2.30   93   3.10   106   3.90   120
100   30   0.49   45   0.88   57   1.20   66   1.64   82   2.30   105   3.08   124   3.85   144
120   36   0.48   50   0.88   61   1.20   70   1.62   90   2.25   121   3.02   142   3.80   165
140   42   0.47   56   0.88   66   1.20   75   1.60   100   2.20   138   2.92   166   3.65   195
160   48   0.47   62   0.87   74   1.20   84   1.60   11   2.20   153   2.85   187       
180   54   0.47   66   0.86   82   1.18   93   1.57   122   2.15   165   2.75   205       
200   60   0.45   74   0.85   89   1.16   101   1.56   133   2.15   180               
240   72   0.44   90   0.83   105   1.14   117   1.54   152   2.15   204               
280   84   0.41   102   0.81   120   1.12   135   1.51   175                       
320   96   0.41   120   0.79   138   1.10   153   1.48   196                       
360   108   0.41   1345   0.46   154   1.05   171                               
400   120   0.40   150   0.73   176   1.00   198                               
440   132   0.39   168   0.70   202                               

[Frank S]

Information taken Directly from the Dankoff site
DANKOFF
SLOWPUMP® SOLAR PUMP
MODELS: 1300,1400,2500,2600
Use Solar-Electric Power to provide 200-2,600 Gallons per Day (750-10,000 ltrs.) from shallow water sources. Slowpump can push water as high as 450 vertical feet (137m).

Solar Slowpump was the world's first commercially available low power solar pump. It was developed by Windy Dankoff in 1983, in response to those who said "that's impossible." Thousands of Slowpumps have been installed worldwide by ranchers, homeowners, missionaries, health workers, government agencies, etc. Some of our oldest Slowpumps are still in daily service.

Slowpump is not submersible, but can draw water from shallow wells, springs, cisterns, tanks, ponds, rivers, and streams, and push it as high as 450 vertical feet and through miles (kilometers) of pipeline. Slow pumping minimizes the size and cost of the solar array, wire and piping.

Slowpump is less expensive than sub-mersible DC pumps, and made in a much wider range of sizes. Wearing parts typically last 5 to 10 years. Overall life expectancy is 15-20 years.

"The Slowpump #2507-24V is supplying water for a work camp on the outer island of Onotoa. It's supplying water for 60 people. The well is one half mile 800m away from the camp." -- B.C., Ministry of Works and Energy, Kiribati, South Pacific

"I have been very happy with the 1308 Solar Slowpump!...We are using it in a 5 meter deep hand dug well in a valley, and pumping 200 meters distant and 50 meters vertically." ---
Dr. D.L., World Missions, Cameroon, W. Africa

"These pumps work great.... Even during low light levels when the motor is turning slowly, a small amount of water can be pumped.... The manual is easy to read. Windy's troubleshooting section is excellent....Not only have these pumps stood the test of time, but small changes have made them even better." --- B. Schultze -product review in Home Power Magazine #42

CONSTRUCTION & FEATURES
Rotary vane mechanism (positive displacement) made of forged brass, carbon-graphite and stainless steel
NSF® approved for drinking water
Handles sea water, dissolved minerals
Survives most freezes
Permanent magnet, DC motor
AC models use a low-surge PM motor that greatly reduces starting surges, inverter and wire size requirements
Installation and Service Manual is highly detailed and illustrated
Reading the Performance Chart

Total Lift = Vertical Distance from surface of the water source to the pipe outlet or top of storage tank, plus any pipe friction loss
Suction Capacity

20 vertical feet (6 m) at sea level -- subtract 1 ft. for every 1000 ft. altitude (1 m for every 1000 m). Pump should be mounted as close to the water source as possible.
Filtration Requirement

This pump CANNOT tolerate dirt. Water MUST be filtered to <10 microns using a disposable cartridge filter. If water is very dirty, prefilter it, improve the source, or consider a different pump.
PV-Direct (non-battery) Requirements

The rated power of the PV array must exceed the pump watts by 20% or more.
A Linear Current Booster (controller) is required to function in varying light conditions (12V/24V: 5Amp, 8Amp, 15Amp, 48V: 10Amp)
Solar Tracker (optional) to increase daily yield (40-55% in summer)
Accessories

Intake Strainer/Foot Valve with fine monel metal screen, stops course debris
Inline 10 micron Filter (10-inch) uses standard drinking water cartridges
Intake Filter/Foot Valve (30-inch) replaces Intake Strainer and Inline Filter (10 micron) with a single unit, best for lowering into a shallow well
Spare Filter Cartridges (5 or 10 micron spun fiber)
Dry Run Switch prevents battery drain and pump damage if water source
runs dry
Linear Current Boosters (LCB) for PV-Direct (12V/24V: 5Amp, 8Amp, 15Amp, 48V: 10Amp)
Fittings

1300/1400 Series: 1/2 inch female pipe thread
2500/2600 Series: 3/4 inch male thread
Dimensions (1300/2500-Series)

5.7 x 15.5 inches (14 x 39 cm)
Weight 16 lbs (7 kg)
Warranty

1 year against defects in materials and workmanship. Use of pump without 10 micron or less filter will void warranty.

Surface Pumps Comparison
Surface pumps for lifting and/or pressurizing water / 1 PSI = 2.307 ft. of
Surface Pumps   Min Lift (ft)   Max Lift (ft)   Min Lift (PSI)   Max Lift (PSI)   Min GPM   Max GPM   Pump Type   Dirt Tolerant   Filtration Required   Dry-run Tolerant
Solar Slowpumps 15xxx*
0   440   0   191   0.4   4   rotary vane   N   10 mic   N
Solar Slowpumps 14xx and 26xx
160   440   69   191   1   4   rotary vane   N   10 mic   N
Flowlight Booster Pumps 16xxx**
69   150   30   65   3   4   rotary vane   N   10 mic   N
SunCentric Pumps 7xxx
0   90   0   39   5   70   centrifugal   high   N   Y
SolarForce PistonPumps 30xx
0   220   0   95   4   9   piston   medium   N   Y
Solaram Pumps 8xxx
0   960   0   416   3   9   diaphragm   medium   N   Y