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Dankoff Solar Pumps

Dankoff Solar Pumps

Dankoff Solar Pumps manufactures several types of low-power, high-performance pumps for use in off-grid DC systems.

Slowpump

The Slowpump can push water up a hill as high as 450 vertical feet. It runs on very low power, with or without batteries, to supply between 200 and 2,600 gallons per day. The rotary vane pump mechanism is housed in forged brass for durability. Because of tight tolerances, the water must be very clean, so fine filtration is required to protect the pump (5 micron filtration is recommended).

The Slowpump chart shows the gallons per minute (GPM) output from the pump and power (Watts) consumed by the pump for various vertical lifts (this is the "total head" or the lift from the water level at the source to the top of the storage tank, in actual elevation change, not pipe distance).

The pump performance in the chart is measured at array-direct voltages. The peak power voltage of a nominal 12 VDC PV module is about 17.5 VDC. A battery-powered pump will have 10-20% lower output and power draw because the battery is operating at a lower voltage. Flow rates are in GPM. To estimate gallons per day delivered, multiply the GPM by 60 (minutes) to get the gallons per hour (GPH) amount. Then multiply by the peak-sun-hours per day at the site location (this data is available from NREL's PVWATTS Solar Calculator) to get the gallons per day (GPD).

For PV-direct operation (without batteries), the PV array nameplate output must exceed the required pump wattage by at least 20%. Over-sizing the array will increase the amount of water delivered per day because a higher wattage array will produce the pump's required wattage in less light, allowing the pump to run at full speed for more hours each day, or in cloudy weather. For example, a 100 W module will produce 50 W in one half the amount of sunlight present at noon. The extra available power will not damage the pump as long as the array voltage is within the voltage range of the pump motor.

For array-direct operation, a linear current booster (LCB) with the required output amperage must be used (see LCBs listed at the end of Water Pumping.) To find the amperage needed, divide the motor voltage by the required pump wattage. AC models use a low-surge permanent magnet motor that greatly reduces starting surge, relieving stress on inverters and generators.

Slowpumps have a suction lift of up to 20' at sea level. Subtract 1' for each 1,000' above sea level. These pumps cannot run dry without damage, so the optional dry-run switch is recommended. Wearing parts are replaceable and typically last 5-10 years, and overall life expectancy is 15-20 years.

Slowpumps are NSF approved for pumping potable water. Slowpumps can also be used to pump saltwater. Dimensions: 5.7"W x 15.5"L. Weight 16 lbs. 1-year warranty.

¼ HP Slowpumps (model series 1300 and 2500) are available with 12 or 24 VDC motors, for use with 12 VDC and 24 VDC array-direct or battery systems. These are also available in 120 VAC versions for inverter, generator, or grid connection. ½" female pipe fittings.

½ HP Slowpumps (model series 1400 and 2600) are available with 24 or 48 VDC motors, for use with 24 or 48 VDC battery systems, or PV direct with a 36 VDC nominal array. Also available in 120 VAC versions for inverter, generator, or grid connection. ¾" male pipe fittings.


Vertical lift
(head)(ft)

Slowpump model, performance, and power requirement

1322 1310 1308 1304 1303 2503 2507 1403 2605 2607

GPM

W

GPM

W

GPM

W

GPM

W

GPM

W

GPM

W

GPM

W

20

0.51

27

0.92

29

1.25

30

1.75

37

2.50

48

3.25

52

4.00

57

40

0.51

32

0.92

41

1.25

48

1.75

53

2.50

60

3.23

69

3.95

78

60

0.51

36

0.89

46

1.20

54

1.68

64

2.40

78

3.15

90

3.90

102

80

0.49

40

0.88

51

1.20

60

1.64

73

2.30

93

3.10

106

3.90

120

100

0.49

45

0.88

57

1.20

66

1.64

82

2.30

105

3.08

124

3.85

144

120

0.48

50

0.88

61

1.20

70

1.62

90

2.25

121

3.02

142

3.80

165

140

0.47

56

0.88

66

1.20

75

1.60

100

2.20

138

2.92

166

3.65

195

GPM

W

160

0.47

62

0.87

74

1.20

84

1.60

112

2.20

153

2.85

187

GPM

W

4.30

283

180

0.47

66

0.86

82

1.18

93

1.57

122

2.15

165

2.75

205

3.35

280

4.25

305

200

0.45

74

0.85

89

1.16

101

1.56

133

2.15

180

GPM

W

3.33

296

4.20

338

240

0.44

90

0.83

105

1.14

117

1.54

152

2.15

204

1404

2.55

266

3.30

331

4.05

396

280

0.41

102

0.81

120

1.12

135

1.51

175

GPM

W

2.50

302

3.25

373

4.00

444

320

0.41

120

0.79

138

1.10

153

1.48

196

1.66

255

2.50

338

3.20

410

360

0.41

134

0.76

154

1.05

171

1408

1.62

280

2.50

374

3.16

450

400

0.40

150

0.73

176

1.00

198

GPM

W

1.64

312

2.50

406

440

0.39

168

0.70

202

1.10

269

1.66

342

2.50

451



Dankoff Slowpumps

Model Item Code
12 V PV
direct or battery
24 V PV
direct or battery
24 V
battery only
36 V PV
direct or 48 VDC battery
120 VAC

1303

1/4

075-04172

075-04174

--

--

075-04139

1304

075-04155

075-04157

--

--

075-04138

1308

075-04160

075-04162

--

--

075-04137

13010

075-04163

075-04165

--

--

075-04136

1322

075-04168

075-04170

--

--

075-04135

2505

075-04175

075-04177

--

--

075-04140

2507

075-04180

075-04182

--

--

075-04141

1403

1/2

--

--

075-04193

075-04195

075-04144

1404

--

--

075-04189

075-04191

075-04143

1408

--

--

075-04185

075-04187

075-04142

2605

--

--

075-04197

075-04199

075-04145

2607

--

--

075-04201

075-04203

075-04146


Dankoff Slowpump Accessories

Inline filter – this is a plastic filter housing with ¾" female pipe thread inlet and outlet fittings. Filter cartridges ordered separately.

30" Intake Filter /Foot Valve – this filter replaces an intake strainer and foot valve in a single unit. Use with silty streams or other problem applications. A spare 30" filter cartridge is included. ¾" female pipe fitting.

Dry-Run Switch – this switch provides automatic shut-off in case the pump runs dry. Order the correct model for the Slowpump that you are using.


Dankoff Slowpump Accessories

Description Weight Item Code

Dry-Run Switch - for 1300 and 1400 series Slowpumps

1

075-04213

Dry-Run Switch - for 2500 and 2600 series Slowpumps

1

075-04215

Inline filter housing - 10" with 3/4" female NPT pipe ports

3

078-01125

Filter for above housing - 10", 5-micron (2 pack)

4

078-01130

30" filter and foot valve assembly

3

075-04207

Filter cartridge for 30" filter assembly above (3 pack)

6

075-04209

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