What is a DC Pump?

A DC pump is essentially a pump that is operated on DC (direct current) instead of the usual AC power found in most homes. The fact that these pumps operate on DC means an inverter is not required; so even the most basic of system can operate a DC pump. Some DC pumps can operate directly from a solar module (the El Sid PV models as well as the ShurFlo 9300 using a controller). Other DC pumps must be connected to a battery as they can be damaged with voltages of 16 or higher. We stock two types of DC pumps...DC circulating pumps and DC submersible pressure pumps.

DC Circulating Pumps

A standard "off-the-shelf" AC (120/240 volt) circulating pump can consume 100 or more watts, twenty four (24) hours a day. For a grid connected home this costs the homeowner a negligible amount of money. However for an off grid home, this constant consumption of electricity, can be very expensive. When you consider this extra energy is required during the winter, when solar energy is the most scarce, a standard circulating pump can be impossible to operate without substantially increasing the output of your solar system. Ivan Labs Inc. has come up with a solution...the El Sid pumps.

The El Sid DC (direct current) circulating pumps made by Ivan Labs Inc. have made solar hot water, outdoor wood boilers, indoor wood boilers and radiant heat systems possible without spending large amounts of money on increasing your solar system. They are called El Sid pumps. These DC circulating pumps can operate on as little as 3.5 watts (SID3.5PV). They also have models that operate on 5 watts (SID5PV), 10 watts (SID10PV, SID10B12, SID10B24) and 20 watts (SID20PV, SID20B12). The El Sid pumps have the following advantages over a standard off-the-shelf circulating pump: brushless  high efficiency (3.5, 5, 10, or 20 watts)  operate DC or AC (using a wall adapter)  good for high temperature (up to 250oF  good for high pressure (up to 175 psi)  magnetic coupled drive  no shaft  no fan  corrosion proof (brass and stainless)  lightweight (2 lbs)  maintenance free  very quiet  no seals to leak  no bearings to overheat  very small (2 ¾" x 3")  All of the Ivan Labs Inc. El Sid pumps look identical and have the same bronze and stainless steel housing and impeller. The only differences are the power consumption, voltage, application, head and flow rates. The exception is the 20 watt models. The drivers for both of these look slightly different with a heat sink built on to the driver (as seen below).

The Ivan Labs Inc. DC circulating pumps that have PV on the end of the model number are designed to operate directly from a solar module or modules. They can accept the power directly from the module up to 20 volts DC (SID3.5PV, SID5PV, SID10PV, SID20PV). The PV models will actually operate fine directly from a battery but with reduced head and flow as the battery voltage is slightly less than a solar module voltage. These PV direct DC circulating pumps are usually connected directly to a solar module, with no controls, in a solar hot water system. When the sun shines, the pump turns on automatically, circulating the liquid through a hot water collector, transferring the heat. When the sun goes down the system turns off automatically. This makes a very simple system with no complicated or expensive controls.

The El Sid models that have a B in the part number are designed to operate from a battery. Using several El Sid pumps in a radiant heat system allows each zone (pump) to be controlled by a different thermostat. The battery models operate on a lower voltage than the PV models. They can operate from 8 to 16 volts DC (SID10B12, SID20B12) and 20 to 35 volts (SID10B24). The battery models cannot operate directly from a solar module as the unregulated higher voltage will damage the pumps.

Specifications:

 Ivan Labs Inc. now makes temperature differential controllers that will turn the El Sid pumps on and off automatically. Ivan Labs Inc. calls them 2W2 DELTA temperature controllers. The 2W2 DELTA controllers are available in two different voltages...12 volts DC (2W2DELTA/12) and 24 volts DC (2W2DELTA/24). The 12 volt El Sid DC pumps require a 2W2DELTA/12 and the 24 volt El Sid DC pumps require a 2W2DELTA/24. These controllers have a sensor for the solar collector and a sensor for the storage tank (or concrete floor in a radiant heat application). When the water/antifreeze in the collector is warmer than the storage tank or floor the pump(s) turn on. If the collector is cooler than the tank, the pump(s) turn off. This system is very reliable and simple to operate. El Sid pumps will not wear out from cycling on and off as there are no brushes. The electronic module for the 2W2 DELTA temperature controllers mount directly on the El Sid pump and require very little space.

ART-TEC Solar now manufactures two different high quality low cost temperature differential controllers that are perfect for use with any of the El Sid DC circulating pumps or any other 12/24 volt high efficiency pump. They are:

The DTC-1 temperature differential controllers....This low cost 12/24 volt temperature differential controller is the simplest, most reliable temperature differential controller in production. Using two sensors, it compares the temperature of the solar collector/indoor boiler/outdoor boiler versus the temperature of the storage tank/radiant floor. If the solar hot water solar collector/indoor boiler/outdoor boiler is warmer than the storage tank/radiant floor  by 1oF or more the ART-TEC Solar DTC-1 turns the pump on and keeps it on until either the solar collector cools down or the storage tank heats up. For more information on ART-TEC Solar's DTC-1 please click here.

The DTC-AT temperature differential controllers...This 12/24 volt temperature differential controller operates very much like its predecessor however it has a few extra features: The temperature differential is adjustable from 5oF to 35oF to give the user much more accuracy and efficiency depending on the application; the ART-TEC Solar DTC-AT also has an adjustable over temperature shutdown function that will turn the pump(s) off when the storage tank or radiant floor becomes too hot. For more information on ART-TEC Solar's DTC-AT please click here.

DC Submersible Pumps

Most submersible well pumps in North America operate from either 120 or 240 Volt AC electricity. Standard off-the-shelf submersible pumps can have huge power requirements. Here are the requirements of a typical stand submersible well pump we have found to be common in Canada and the US.

For our illustration we have decided to use a Gould's Pumps 4 inch 120 volt submersible well pump.

From the chart we can see the pump is a 120 volt 1/2 horsepower pump. It is rated at .37 kW (½ hp) or 370 watts. It actually consumes 7.4 amps or 888 watts the whole time the pump is running after the startup surge. The startup surge or locked rotor consumption is 4368 watts. So you cannot tell what type of inverter is required just by knowing the hp of the pump.

If you sized the inverter just by the rated kW of the pump you would have tried a 400 watt or so inverter. That would not be large enough to even make the pump turn and could possibly destroy the inverter in seconds.

If you then decided to buy an inverter large enough for the full load amps of the pump you would have tried a 1000 watt or so inverter. The pump still would not turn and the inverter would be overloaded.

The most important spec when sizing an inverter is to look at the locked rotor amps (LRA) or the pump. This can be up to 7 times the wattage of the full load amps. For this pump it is about 5 times the full load rating. When looking at this pump we would need a high quality inverter capable of handling 4368 watts for at least 5 seconds. An Outback FX3048 or VFX3648 would have no trouble operating this pump. The inexpensive 4000 watt inverters like those sold at Canadian Tire will probably not operate this pump.

If you are designing a large system to power an entire home or cottage this standard submersible would be an acceptable pump to use as you will likely have a large high quality inverter.

If, however, you are designing a system to water cattle or have a small system with a small inverter a 120/240 volt off-the-shelf submersible pump is not the logical choice. In this case it makes sense to use a high quality DC submersible pump like a SHURflo 9300 with a 12-24 volt battery bank or PV direct using a 902-100 or 902-200 pump controller. These 9300 pumps operate from 12-24 volts DC and have low power and surge requirements. At 100 feet of lift SHURflo's 9300 pump only consumes 2.9 amps at 24 volts (70 watts). The SHURflo 9300 can operate on 12 volts but the output will be about 40-50% compared to operating the pump at 24 volts.   For more info on the DC submersible pumps made by SHURflo click here.

SHURflo's 902-100 pump controller is a PV direct 24 volt unit designed to allow the pump to operate direct from a 24 volt solar module. It requires a 100-150 watt 24 volt module and must be installed in a clean and dry area. A float switch can be added to the 902-100 for automatic pumping.

SHURflo's 902-200 allows the 9300 circulating pump from a 12 or 24 volt module from 100-150 watts. It is housed in a water tight enclosure and has the capability to monitor water level as well as includes an on/off switch. A float switch can be added to the 902-200 for automatic pumping.

The following links will take you to the specific DC Pumps...

For a list of all DC Pumps click here! or choose by type below...