How we built Russia's first electric vehicle refueling from solar energy

    Somewhere in late July, I had a chance to talk with the initiative group of St. Petersburg Polytechnic University of Peter the Great. A team of students intends to build an electric car that works only from solar energy. This is a matter of the near future, and I wanted to do something interesting right now. So it was decided to open the first in Russia refueling for electric vehicles, working from the sun.

    It all started with such a pattern, but about what happened - under the cut.



    The opening of the filling was timed to the GREENDAY International Ecological Festival , held in St. Petersburg on October 1, 2016.

    Calculations and design


    First of all, we decided to decide what we want and what we should get? After shallowing ideas, like “to always work and charge everything,” they began to formulate terms of reference. Basic requirements for refueling:

    • Year-round work
    • Work around the clock
    • Refueling operation regardless of weather conditions
    • Simultaneous charging up to 2 cars
    • Equipment reliability
    • Refueling should be free for electric vehicle owners.

    And if the last point was resolved by the Polytech team, then everything else had to be considered, estimated and carried out calculations.

    As a starting point, we took the car Nissan Leaf. Its power supply, which can be connected to a normal 220V network, is rated at 10A, that is, a power consumption of 2.2 kW. Judging fairly that such a restriction is imposed due to the possibilities of home wiring, where such a charger can be connected, we measured the consumption of an electric vehicle when charging from a “gas station” - it was 3.3 kW. Then simple mathematics went: in order to charge two cars, you need at least 6.6 kW of power, well, taking into account the growth of consumption, we are laying 30%. Thus, our station should produce at least 9 kW of power.

    Also, the gas station should be “green”, which means that we use renewable energy sources - the sun and the wind. Taking into account the geography of the location (St. Petersburg), it was quite possible to install a wind turbine, but the wind is not constant, and the houses are all around, and the wind turbine is quite noticeably noisy on revolutions when energy is generated. Therefore, it was decided to use only solar panels.

    When the question arose about the equipment, it is quite expected that they began to choose from European / American manufacturers and Russian ones. China was not considered due to low reliability, and the operating conditions provided for the most severe. Therefore, it was decided to contact the Russian manufacturer of inverters and solar controllers - the company MicroART. They are manufacturers and they also have the largest experience in the country in assembling and operating autonomous solar power plants. With this we killed two birds with one stone: we chose reliable equipment and ensured the simplicity of warranty and service.

    Equipment selection


    As already mentioned, the calculation was based on the consumption of two cars and a power reserve of 30%. So the inverter MAP Dominator 9 kW was selected . Since the currents at such a power are quite high, the choice was on a 48 Volt model. The same inverter is equipped with a built-in computer that allows you to remotely monitor and control some of the device settings.


    By the number of panels, they were solved for a long time, but they came to the conclusion that there is no need to fully reserve the power consumption of an electric vehicle from the sun and set the optimum - 12 pieces of 200 watts of single-crystal silicon . The peculiarity of the panels is that the frame itself and the sealing film are black, and therefore in winter they heat up a bit and the snow comes off faster, which means they should be cleaned less often. Last but not least, the seller’s warranty of 12 years.


    Since the panels were assembled at 2400 W, and the battery assembly was at 48 V, currents can easily reach 50A. Taking into account the fact that on a bright winter day, the power of solar panels can grow up to 110-120% of the declared amount, it is necessary to take it with a margin. From the manufacturer’s line, we take the closest controller to 60A and add the technological reserve - we get the IES DOMINATOR MPPT 200/100 . This controller is capable of receiving voltages up to 200 Volts and delivering charging current up to 100 Amps!


    Since the station will work all year round and around the clock, it is necessary either to fence a huge battery bank or to provide external recharge. Taking into account the fact that the cost of batteries in a solar power station can reach 50-70%, it was more logical to have an external wire to the station. But batteries are required for buffer. In addition, they will ensure the functioning of the gas station and adjacent objects in the event of a power outage BP . In principle, such a power plant is capable of providing autonomous power to a cottage of 200-300 square meters, as soon as the capacity of the battery is increased.

    Batteries we chose AGM, front-terminal FST 150-12with a capacity of 150 Ah. That is, they store up to 7.2 kWh * h of energy, and this is enough to charge one car if there is no sun or external power. With a low battery charge, the inverter will not allow them to be killed and simply turn off external consumers.


    We collect and run


    As always, the preparation and organization of the process takes the most time. The assembly of the power plant itself took about 10 hours from the moment of arrival and until the end of the prompting of beauty. Very much helped out by a lift, due to which it was not necessary to run with ladders and lift heavy panels over them.


    For the storage of all equipment, a metal vandal-resistant cabinet was chosen with equipment fastening in a 19 "rack.


    And while the people masterfully held on to the air and fastened solar panels to this monstrous design, which, by the way, was counting on St. Petersburg wind loads.


    I started assembling the cabinet and checking the equipment.


    When the equipment was mounted and wires were connected, everything started without any extra dancing with a tambourine. Now just bring beauty.


    Towards the end of the work, something like a project began to emerge. It remained only to fix and remove all the wires.


    On board hung a "refueling gun" with a controller, on which, by the way, you can set the charge current. He also keeps records of watts * hours, which were "filled" in the battery.


    Well, then went to the opening, exponential cutting the ribbon and the first charging of the electric vehicle.



    Total


    In two months, the path from the idea to a solar-powered electric refueling station was covered. MPPT-controller, together with a hybrid inverter, allows maximum use of solar energy. The built-in computer makes it possible to monitor the status of all elements (even the temperature of the batteries) to take the necessary measures remotely and quickly.

    There is also a reserve for the future: the inverter already has the function of selling energy to the network. For example, during the daytime, energy is sold to the network from the sun, and at night this energy is consumed while the electric car is standing and charging. As a result, you can stay in the black. It remains only to wait for the adoption of the relevant law, since at the moment the sale of electricity by private individuals is not provided. In any case, the gas station can be used free of charge at a guarded parking lot at the address: St. Petersburg, Gidrotekhnikov St., 5.

    Also popular now: