A battery-less , portable , high flow solar PV pump which is ready to replace diesel pumps in Bihar


General Description: Our Portable Solar PV Water Pumping System can  deliver upto  70,000 Ltrs per day from a 4 inch bore well, which is common in Bihar farmlands. These are actual photos from the installation at Pune, undergoing trials over the past several months.

  • The system will last for at least 10 years with  NO running cost .
  • Due to its impressive output and portability , farmers will be proud to own this powerful solar water pumping system. 
  • Please see the video clip of the output on a clear day from 1200 watts .
  • This will save him time besides having many additional uses which can increase his income and improve rural life. 
  • Water merchants can irrigate 7 hectares a week.
  • I would call it just ‘plug and pump’.
  • No batteries are used for water pumping and as a back up,  they can also run on regular grid supply when it becomes available.
  • The system consists of a pump, controller, solar panels and a  cart.
  • Our effort has been to come as close as possible to the output of diesel pumps that we are trying to replace, within the budget specified.

    Details below:

    The Pump:  We use off the shelf regular , submersible AC pumps, a 1 Hp or 0.75 Hp can be used. They pump 10,000 LPH and 8000 LPH respectively at 10m head. Flow  at 5 m head is substantially higher. Made in India, robust and proven work horse in Indian agri conditions, locally rewindable and repairable. They fit into a 4 inch bore well. Life 10 years+. A mesh is fitted at the inlet to keep out debris. (Photo 1 shows actual output from a 1 hp submersible with 1200W solar panels.) We will also offer a surface pump ,as suggested by Mr Dankoff, in places where water level does not drop below 6 m.

    The Solar Panels: 1200W (100W x 12) for 1 hp pump or 960 W (80W x 12) for 0.75hp. A tiny sprinkler is provided to keep panels cool and clean to ensure max efficiency. Small panels are provided so in case of accident / damage to minimise loss. We have presently tried out  poly-crystalline solar panels which were easily available to us. As suggested by our expert AnudeepYadav , we plan to use mono-crystalline modules which may improve performance and portability. Life 10 + years.

    The Controller:  Developed by us, using off the shelf inverter components, converts DC from solar panels to AC  to power the pump. It provides soft start and stop enhancing motor life, dry run protection, MPPT automatically adjusts pump RPM with available sunlight. This increases daily operating time. Life 5 to 10 years. See the video showing the flow increasing gradually due to the soft start feature.

    We will provide instructions on a video CD and a booklet in Hindi.

    The Cart: It is a modified local cart as shown in photos . It will be built in local workshops using solid rubber tyres (which never go flat)and 8 mm rebar spoked,  29" dia wheels like the cart for diesel pumps. Angle of the array can be changed easily for daily and seasonal tracking of the sun. It rests at an angle of 26 degrees , the average latitude in Bihar. Every couple of hours  the cart can be turned easily to face the sun. A perpendicular “shadow stick” is provided to help farmer track better. The  pump and controller will be stowed in a box under the cart. Securing pegs are provided so that it does not topple in gusty winds.Rubber pads and dampers  protect the solar panels from damage during transport on rough country roads. The cart  is to be pulled by human or animal power  at 3 to 5 kilometers per hour.

    Additional uses: When pump is not used, the massive 1200W array can be used to charge a battery bank, which can be used for lighting, fans, TV, radios, computers, etc. If used just for lighting with CFL / LED’s, the farmer can light up several houses in the vicinity and even get some additional income for the service. It can directly run (without battery) a  normal fridge or deep freezer during day which will help preserve shelf life of food and milk products this is something essential missing from rural India due to lack of electricity.

    Costing: The Submersible pump range is available from Rs 7,000 to 15,000 depending on the brand, materials used. Solar panels Rs 40 to Rs 50 per W. Controller Rs 25,000.

    So depending on the type/brand of pumps and solar panels used a 1 HP, 1200W system will cost between Rs 80,000 to Rs 100,000/-.

    A cheaper alternative 0.75 HP pump can also be used with just 960W solar panels costing about Rs 70,000 to 90,000/-

    Cost of the cart and frame is Rs 9,000/-.

    Bulk orders will drive down costs further; making it a profitable, fast growing and  sustainable venture.

     Previous experience: We have been experimenting with different types of solar pumps for 3 years. Initially we experimented with pumps and drip irrigation systems which are suitable for  vegetable farms. Our new solar pump designed for Bihar covers all the parameters such as output, portability , cost and simplicity.

    AC submersible pumps vs BLDC pumps:  Our experience with BLDC pumps imported from China was discouraging. BLDC motors have embedded electronics which are sealed and not repairable. Manufacturing them in India is also not possible since they use  rare earth magnets, which is a monopoly of China. China has increased the prices of these magnets 5 fold in the last couple of years.  

    Local solution: I was forced to look for a local solution which does not depend on imported components whose prices can fluctuate so much. All the parts of my solar pumping system are made in India.

     Our pumps are working in Tamilnadu, Karnataka, Maharashtra, Rajasthan, Himachal Pradesh, Bihar and Afghanistan.

    We have tied up with Eric Jensen who plans to manufacture smaller pumps in India . His vast experience in designing and manufacturing will be  very useful for future improvements to our pumps.

    18 Oct 2013 update: 

    Photo of my pump working on a test rig at 0830 hrs  on 18 Oct 2013 . Construction of prototype of cart is underway

    Update 21 Oct 2013: 

    Portability: Requirement as per the various blogs put up by experts and jury is, Diesel pumps are drawn by a bull or horse cart, existing Kirloskar and Bharat diesel pumps are 200 kgs+ .

    My system  weighs 150 kgs. Over 50 kgs lighter. I have  checked 150 kgs can be pulled by one or two people. The solar panels are mounted on three frames of four panels each. They are stacked one above the other during transport.

    Update 22-Oct-2013.


    ·        Pump: Kirloskar, Texmo, CRI, Shakti, Pluga, KSB etc.

    ·        Solar Panels: Poly-crystalline or Mono-crystalline there are dozens of Indian and foreign companies. Which ever offers highest efficiency, competitive prices and good quality. Waree, Vikram Solar, Photonix, Emvee etc are Indian made.

    ·        Controller: Our own innovation. 

    ·        Cart: Existing work shops making them in Bihar.

    Update 25 Oct 2013

    1200 watt solar cart has been assembled. Will take only 10 minutes to fold for transport. It can be moved by one person but a helper is needed for assembly.Please see video No 2. 

    Update 28 Oct 2013

    The pump controller box and a storage tube for submersible pump has been fitted under the solar panels. Please see photo no 8. 

    Update 29 Oct 2013

    Sprinkler to cool and clean panels . Photo no 9. The sprinkler is attached to one of four vertical retaining posts which hold the frames in place when they are stacked up. Any of them will also be useful as a shadow stick to point the frame at the sun.

    Update 02 Nov  2013

    The solar array is designed to rest on one side at an angle of 26 degrees which is the average latitude of Bihar. This angle can be changed according to season by a bamboo prop of suitable height tied to the underside of the frame.

    The solar array also provides a cool, shady spot to rest , for the farmer and his family , in the scorching heat of the sun.

    Update 08Nov 2013

    Assembling is a simple process of placing the 3 m long yoke tubes across on brackets which are provided on the front and back of the cart. Photo no 9 shows placing. The upper and middle frames are then lifted out on to either side and secured to the crossbars with nuts and bolts.

    The pump is now placed in the borewell and connected to the controller.  The solar array is turned to face the sun. Controller is set for low, mid or high output depending time of the day and presence of clouds. It is switched on and tuning knob is turned to ensure steady flow . Dismantling is just reversal of this sequence. 

    Operating the pump is easy for even an illiterate person after a brief training session.

    Update: 13 Nov 2013

    A video of 3 minutes duration showing the testing, assembly and operation of our solar pump has been uploaded . Please see this video to get an overview .

    Update 14 Nov 2013: 

    A consolidated description and calculations have been uploaded.