MIT Technology Review

July 2009

Solar Powered Cycle

The solar electric rickshaw, Soleckshaw, can easen the lives of over five million cycle rickshaw drivers.

Go to any part of India and one would notice colorful hooded tricycles parked in every city street corner or being pedalled away. That’s a cycle rickshaw, a popular mode of transport in congested areas of the city. The rickshaw, as it is commonly called, is the only non-polluting commercial vehicle in India and the sole means of earning livelihood for over 5 million people of India’s 1.14 billion population. And it’s hard work. To pedal or pull a rickshaw with a combined weight of over 150 kg including the passengers entails strenuous manual labor. The task is not only arduous but also causes various ailments to rickshaw drivers.

Now after over 100 years of the rickshaw era, scientists at Council of Scientific and Industrial Research (CSIR), New Delhi have found a pollution-free solution to end the bane of this large populace by developing solar electric rickshaw, named as Soleckshaw. It is a rickshaw that is driven partly by pedal and partly by electric power supplied by a battery that is charged from solar energy. The initiative has come as a small step towards improving life of 800 million people who are living below the poverty line, including 5 million rickshaw-pullers. Though auto rickshaws, vehicles driven on fossil fuel, are also an economical means of transport and are used by millions of commuters, soleckshaw with its zero carbon footprint promises cleaner environment, providing quality of life for rickshaw-pullers without any reliance on fuel.

SAFE

Soleckshaw has been developed by a team of scientists at CSIR national laboratory, Central Mechanical and Engineering Research Institute (CMERI) in Durgapur, West Bengal. The CMERI team has designed it to be a stable and safe vehicle which can be driven economically.

The pedicab is motor-assisted and therefore is likely to be driven easily both on plain area as well as uphill, without any risk of imbalance which currently all rickshaws suffer from. “The override mechanism on the rear axle ensures that both the rear wheels supply equal traction, making up for the balance of the vehicle and ease in taking turns,” explains Gopal Sinha, director at Advanced Institute of Science and Training, New Delhi an independent organization promoted by CSIR. Sinha was the project advisor of soleckshaw. He says, “One of the main aims of soleckshaw is to reduce the effort required to pull a rickshaw. The 36V motor has been used to ‘assist’ the driver in pedalling. Even though it may not relieve him of pedalling, it will definitely make the task almost effortless for him.”

Besides, the rickshaw driver’s seat has been designed to give him more comfort. The seat is adjustable and so he would not have to stand on the pedals all the time. A suspension system has been used to ensure smooth ride. For increased safety of both the driver and the passengers, all the three wheels have the braking system. Aesthetics have also been taken care of and the new pedicab is loaded with features such as headlight, tail lamp, and indicators. For passenger comfort, the soleckshaw has lower footboard which is likely to provide ease mount for everyone, including children, senior citizens, and the disabled.

INSIGHT

So how does the entire machinery work? There is a brush less direct-current (BLDC) motor controller at the centre of the soleckshaw’s handle. The driver inserts and rotates the ignition key provided in the controller to switch on the connection. On the right handle a throttle is provided, which generates power on being rotated. After the connection is established, the driver needs to start pedalling the soleckshaw and then rotate the throttle to get the power at the front wheel. Near the throttle on the right handle a push button is provided to select between two drive modes. The driver can first pedal and then turn the throttle to get assistance from the BLDC motor while pedalling or he could use the throttle first for minimal assistance from the motor and then begin pedalling. The first mode is said to be the most economic and recommended mode. Adopting the first mode will lead to faster pick up of soleckshaw and once it picks up speed the driver will get full assistance from the motor, having to pedal with minimal effort.

The new pedicab with seating capacity of two to three passengers and a payload of 150-200 kg (excluding the driver) is expected to speed up to 15 kmph. The rear wheels of soleckshaw are manually driven while the front wheel is driven by BLDC electric hub motor which is mounted on the wheel. The motor, which weighs approximately 5 kg, is powered by 36V, 18AH lead acid battery which is charged by solar energy. Run on a simple, light transmission system, the soleckshaw’s BLDC hub motor is a traction type motor that is capable of supplying high torque at low speed, with no need for gears on plains. However, for areas where the road gradient is high, a soleckshaw with gears will also be available on order.

For better traction control of the vehicle, sprocket and chain drive are complemented with an override mechanism at the centre of the rear axle. The box type solar battery, weighing approximately 15 kg, has been placed underneath the passenger seat to give easy access for replacement at the solar charging stations. The soleckshaw battery can also be charged with domestic 15 ampere power socket. However, scientists say it will no longer remain a green vehicle if charged with electricity. Therefore, they want the battery to be charged only at the solar charging stations. “There should not be a need to charge the battery with electricity as we plan to make the charged batteries easily available round the clock. Each solar charging station will be able to charge 10 batteries in 24 hours. The stations will be open 24/7 and will be able to save the solar energy in a battery for charging other batteries,” explains Sinha. According to him, the future models of soleckshaw will not have electric power charging facility.

In size, soleckshaw’s body has been customized in different models to suit different terrains and purposes. The hood and seat colours can be customised too. According to CMERI director Gautam Biswas, since the soleckshaw project is in development stage, different materials, both conventional and new, are being tried for optimization. Even different batteries are being used for performance evaluation. The brand finalisation will happen only after obtaining optimum results.

“The Mark I version of soleckshaw has been designed, developed and prototyped by CMERI in record time of eight months. A functional prototype of Mark I version was launched in Delhi in October 2008 for trial and test. The solar charging station for swapping batteries has been set up by the Central Electronics Limited and the BLDC motor has been developed by Crompton Greaves based on the specifications given by CMERI ,” says Amit Jyoti Banerjee, CMERI scientist and project leader (manufacturing) for soleckshaw. Sheila Dikshit, chief minister of Delhi, and Union human resource development minister Kapil Sibal, who was the then minister of science and technology and earth sciences, launched the soleckshaw in October.

After Mark I is tested on ground, Banerjee’s team will focus on improving and developing future models of soleckshaw. According to him, models Mark I Series 1 & 2 (Series 2 is a slimmer and lighter version of Series 1) and Mark II are being tested in Durgapur, Chandni Chowk, and Ghaziabad. A selective model of Mark II soleckshaw is likely to have a solar panel on top. Nevertheless, according to Sinha, it will still need to get its battery charged atthe solar charging station as it may not get completely charged under the sun.

Mark II is slimmer and lighter than Mark I, providing a higher speed limit of up to 30 kmph. Mark III soleckshaw, which is currently just a concept, could be a spacious family vehicle with reclined seats and aerodynamic body. It is expected to be launched before the Commonwealth Games in 2010. Maintenance of a soleckshaw should not be a problem, according to the developers of the vehicle. One battery takes 5-6 hours for charging. However, one needn’t wait for charging as solar charging stations will be set up to provide the facility of replacing a drained battery with a charged one. With a fully charged battery, a soleckshaw can be driven for as much as 30-40 km, giving the driver an opportunity to earn more in a day than what is possible with a manual rickshaw.

COST EFFECTIVE

A soleckshaw is available at Rs 30,000-35,000. The CMERI team is working on ways to reduce the manufacturing cost. When the vehicle gets mass produced the price is expected to come down to Rs 20,000-25,000. Creators of soleckshaw believe it is cost-effective for mass manufacturers. “The cost-effectiveness of soleckshaw has been engineered by optimizing the system around the most appropriate commercially available components. This minimises the capital requirement for a mass manufacturing unit. Only the novel sub-assemblies like the differential drive, the special hub motor with regenerative feature and the light weight solar panel need to be manufactured apart from the chassis,” says Amit Jyoti Banerjee. The technology has been transferred to two companies—Modular Machines, Faridabad and Dean Systems, Kolkata. Moreover, it seems that the Science and Technology wing of Embassy of India in the US is thinking of importing a few soleckshaws to USA .

Banerjee also adds that innovative business models are being evolved with NGOs, banks, environment-loving corporates and manufacturing organizations to make the soleckshaw available to the drivers at the cost of an ordinary rickshaw. Moreover, capital gain from advertisements and carbon credits could be used for subsidizing the cost of soleckshaw. Pradip K Sarmah, executive director, Centre for Rural Development, an NGO in Noida that operates a rickshaw bank among its other services, says, “A normal rickshaw is priced between Rs 8,000 and Rs 10,000. When soleckshaw comes in market, we do not intend to increase the financial burden on the buyer, that is, the rickshaw-puller and the like. For example, currently if a rickshaw-puller pays us an installment of Rs 30 per day for 300 days for a rickshaw worth Rs 9,000, he may pay us the same rental for 600 days to own a soleckshaw worth Rs 20,000. This way we will reduce their drudgery and provide them with a better product to earn more and earn faster to improve their quality of life.”

As the soleckshaw is still in testing phase, a few challenges are yet to be addressed. The soleckshaw models on road are yet to weather the rainy season in India. “It is a key success factor for us. The motor is vulnerable but Crompton Greaves has assured that it has tested the motor under submerged conditions. We want that if the vehicle gets stranded in a flooded street, the motor should be able to pull it out of water. We are going to test that in the coming monsoon,” says Sinha.

“The size and placement of motor and battery were two major challenges we have overcome. The target was to optimize weight and the driving effort of the rickshaw-puller. We were to make a robust design which is highly reliable so that the user does not have to spend on repairs or maintenance for minimum 2-3 years from the time he buys a soleckshaw,” adds Sinha. “Plans to make solar battery charging stations functional across the country are under way. The challenge that remains is to optimize the cost drastically. Currently the cost of setting up one solar station is around Rs 10 lakh. We want to reduce the cost by 50 percent because we would want to set up one station within 3-5 km radius in every location by Commonwealth Games 2010. The cost of charging a battery is Rs 45 at present (which will work for 30–35 km), which is also something we are trying to cut.”

Although CSIR and CMERI are yet to add final touches to soleckshaw, the project is undoubtedly being awaited by a large number of rickshaw-pullers as it promises to change their life for the better.

FUTURE

Toyota Prius will be launched in 2010 offering a solar roof which will power the ventilation system of the car. In future, Toyota may also develop a vehicle that will be powered solely by solar energy. Tata Motors has announced that it will bring an all-electric vehicle with their new Indica EV which will be able to travel 125 miles on a single 8 hour charge. The new India EV is expected to be launched in 2010. CMERI is also trying to develop solar auto rickshaw. It also intends to develop electric cars partially powered by solar energy.

Narayanan Suresh is Group Editor of Technology Review India and Vantika Dixit is Senior Assistant Editor of Technology Review India.