Yash
Your solar power system can not only power your electrical appliances but also charge your electric vehicle (EV).
An Electric vehicle (EV) uses electrical energy to run instead of gasoline or petrol is an electric car.
It uses electricity from the grid for its charging.
(Smarter people use solar electricity)
This electricity gets stored in the rechargeable battery of the car.
This battery in turn provides current to the electric motor and the wheels start moving.
Also, an electric vehicle is a clean source of energy.
If you are planning to charge your electric vehicle in addition to running your electrical appliances then installing a solar power system of right-sizing at your home could be the best option.
Why use Electric Vehicles (EVs)?
Electric vehicles offer many benefits over conventional vehicles running on the roads.
a) Reduce your fuel cost
Conventional vehicles run on gasoline, petrol, diesel, etc. All these are non-renewable sources of energy.
Because of this, their prices are increasing rapidly and fluctuate every year.
Choosing an electric vehicle will hedge you against rising fuel prices.
Now, you don’t need to pay for petrol or diesel, your car is running on less expensive fuel.
b) EVs are Environmentally friendly
The conventional vehicles that run on fossil fuels pollute the environment.
These toxic gases are hazardous to health and the environment.
Nations are searching for green energy options that are environmentally friendly.
And
Running your electrical vehicle is one of them.
c) Your EVs make you energy independent
Now you are no longer dependent on fuel stations to run your electrical vehicles.
You can charge your electric car from a grid supply and the best option is charging using solar power.
Why have an EV charging solar power systems?
The price of solar is falling rapidly and now solar has become even cheaper than the grid prices.
Obviously, one would prefer the cheaper and clean option.
In addition, more and more companies like Tesla, Tata, Nissan, Kia, and Mahindra are coming up with efficient electric cars.
And charging these electric cars with solar is very easy and profitable.
Read: Why solar is a great investment for your retirement?
Why home charging solar station for your EV?
I don’t see too many electric charging stations as other petrol and gas stations.
Although, Tata has crossed a milestone of over 2200 public EV charging stations across 250 cities in India.
Therefore, considering a home charging station could be the right option.
Your electric car will draw the same electricity from the grid as the other electrical appliances draw.
We all know that grid prices are rising.
And charging your electric car using the grid could be a costly option.
Therefore, having a charging station powered by solar panels is an affordable energy solution.
EV charging and solar panels
A basic EV charging system consists of:
- Solar Panels
- String Inverter
- EV charger
The output from the solar inverter is fed to an EV charger that is connected to the electric car.
And the charging starts.
Battery capacity and the range of electric vehicles (EV)
The battery capacity decides how long your car can run on the roads.
It is measured in kWh.
I find these electric batteries in the range of 20 kWh to 100 kWh
The higher the capacity the longer your car can run.
Manufacturers define the distance an electric car covers once its battery is fully charged in terms of Range.
We can find the mileage of an electric car by taking the ratio of its battery capacity to the range.
How much energy is required to travel 1 mile is calculated by dividing the battery capacity by its range.
Let us look at the capacities and the range in miles of a few branded electric car batteries:
| Model | Battery Capacity (kWh) | Range (miles) |
| Tesla Model S | 100 | 370 |
| Hyundai Kona | 64 | 258 |
| Kia Soul EV | 64 | 243 |
| Audi e-tron | 95 | 204 |
| Chevy Bolt EV | 60 | 238 |
| BMW i3 | 42 | 153 |
| Nissan Leaf | 40 | 150 |
| Volks wagon e-golf | 36 | 135 |
| Honda Clarity | 26 | 69 |
EV capacity and range in the Indian market
- Tata Nexon EV Prime (30.2 kWh and 194 miles after full charge)
- MG ZS EV (44.5 kWh and 211 miles)
- Tata Tigor EV (21.5 kWh and 88 miles)
- Hyundai Kona Electric (39.2 kWh and 281 miles)
- Mahindra e2o Plus (10.08 kWh and 62 miles)
Electric Vehicles (EVs) battery life and warranties
The battery manufacturer gives a warranty in terms of years and specific numbers of miles driven by the car.
For example, Nissan Leaf gives 8 years/100000 miles warranty at 75%.
This warranty assures that the battery capacity will not drop below 75% of its maximum capacity, not before 8 years or 1,00,000 miles.
For example, if the battery capacity is 100 kWh, you will get at least 75 kWh when you fully charge it after 8 years.
Factors affecting the battery life of an EV
i) High Temperature
Operating your electric car during high temperatures can have detrimental effects on its battery. It increases its internal resistance and your car gets less current.
ii) Deep discharge
Never discharge the battery completely, it reduces the battery cycles over time which affects its life. The manufacturers define the current extracting limit of the battery in terms of its DOD (Depth Of Discharge)
iii) High discharge
Keep your driving habits clean and pulling too much current in a short time can affect the battery life. Therefore, it is advisable not to accelerate quickly.
iv) Overcharging
Although there is a built-in battery management system that detects the overcharging of the battery. But it is a good practice, not the overcharge of the battery.
How much electricity does EV consume?
Okay, let us first know the energy consumed when you drive a mile.
This can be found by dividing battery capacity by its range.
Energy consumed per mile = Battery Capacity (kWh)/Range (miles)
For example, you have an electric car with a 100 kWh battery and a range of 250 miles.
It will consume 100 kWh/250 miles = 0.4 kWh per mile.
And when you drive 10 miles, the energy consumption is 0.4×10 = 4 kWh
For 20 miles, it is 0.4 x 20 = 8 kWh
The energy consumption varies.
I can simply say that the energy your electric car consumes in a day depends on your driving needs.
- Less use, less energy consumption
- Moderate use
- Heavy use: Your car needs more energy
Let us work out averages.
(When things get complex, take the average)
On average in the USA, the average American travels 25.9 miles per day.
On the basis of this:
Daily Energy Consumed = (Battery Capacity/Range) x Average travel per day
Let us take out the average energy required by the different electric car models when you drive 25.9 miles in a day:
| Model | Energy Consumed |
| Tesla | = (100/370) x 25.9 = 7 kWh per day |
| Hyundai Kona | = (64/258) x 25.9 = 6.4 kWh per day |
| Kia Soul EV | = (64/243) x 25.9 = 6.8 kWh per day |
| Audi e-tron | = (95/204) x 25.9 = 12 kWh per day |
| Chevy Bolt EV | = (60/238) x 25.9 = 6.5 kWh per day |
| BMW i3 | = (42/153) x 25.9 = 7.1 kWh per day |
| Nissan Leaf | = (40/150) x 25.9 = 6.9 kWh per day |
| Volks wagon e-Golf | = (36/135) x 25.9 = 6.9 kWh per day |
| Honda clarity | = 26/69 x 25.9 = 9.7 kWh per day |
EVs on Indian roads
When I look at the Indian roads, the average travel distance is 35 km or 21.7 miles per day.
Let us look at the energy consumed by different electric cars when an Indian car owner drives 21.7 miles in a day.
| Model | Daily Energy Consumption |
| Tata Nexon EV | = (30.2/194) x 21.7 = 3.4 kWh per day |
| MG ZS EV | = (44.5/211) x 21.7 = 4.6 kWh per day |
| Tata Tigor EV | = (21.5/88) x 21.7 = 5.3 kWh per day |
| Hyundai Kona Electric | = (39.2/281) x 21.7 = 3 kWh per day |
| Mahindra e2o Plus | = (10.08/62) x 21.7 = 3.5 kWh per day |
Factors affecting solar panel sizing of EV
Two main factors that decide the sizing of the solar panels are:
- Sunlight intensity or Peak Sun Hours
- The efficiency of the system
If a region receives good sunlight, then fewer panels can charge your electric car battery.
While on another hand, poor sunlight increases the number of panels and it will cost you more to charge your electric vehicle.
Another important parameter in sizing solar panels is the efficiency of the system.
In a system with efficient solar panels, the losses would be less and it will provide more current to charge your electric vehicle.
While a system with more losses will deliver less current and it will take more time to charge the vehicle.
I can list a few of them in the system:
- Temperature-related losses (solar panels produce less current at high temperatures)
- Dirt losses
- Shading losses
- Conversion losses, transfer losses, etc
When I consider all the losses in the system, it can reduce the output by up to 20%.
Sizing solar panels for EV
Let size the solar panels on the basis of above mentioned two factors.
Assuming, that peak sun hours (PSH) in your region are 5 PSH
(It could be less or more, depending upon the proximity of your location to the equator and the water content in the atmosphere).
When I consider 5 Peak sun hours in a day:
Solar Panel Size (ideal condition when no losses) = Daily energy consumed from electric battery (kWH)/PSH
But the system is not 100% efficient.
when I consider the whole system is 80% efficient or it losses 20% of the output current. In that case:
Panel size with losses = Daily energy consumed from electric battery (kWH)/ (PSH x 0.8)
Let us look at the solar panels required to charge the batteries of different models.
This sizing is based on the assumption that you drive 25.9 miles in a day (USA average travel distance per day)
International market:
| Model | Solar Panel Size (kW) |
| Tesla: | = 7 kWh/(5×0.8) = 1.75 kW |
| Hyundai Kona | = 6.4 kWh/(5×0.8) = 1.6 kW |
| Kia Soul EV | = 6.8 kWh/(5×0.8) = 1.7 kW |
| Audi e-tron | = 12 kWh/(5 x 0.8) = 3 kW |
| Chevy Bolt EV | = 6.5 kWh/(5 x 0.8) = 1.625 kW |
| BMW i3 | = 7.1 kWh/(5×0.8) = 1.775 kW |
| Nissan Leaf | = 6.9 kWh/(5×0.8) = 1.725 kW |
| Volks wagon e-Golf | = 6.9 kWh/(5×0.8) = 1.725 |
| Honda clarity | = 9.7 kWh/(5×0.8) = 2.425 kW |
Average size of the solar panels for international market= (1.75 + 3 + 1.6 + 1.7 + 1.625 + 1.775 + 1.725 + 1.725 + 1.725 + 2.425)/10 = around 2 kW
6 solar panels of 320 watts can provide enough energy to meet daily travel need of 21.7 miles. (*When sunlight is 5 PSH & system losses are 20%)
Solar Panel sizing of EV for the Indian Market
| Model | Panel Size (kW) |
| Tata Nexon EV | = 3.4 kWh/ (5×0.8) = 0.85 kW |
| MG ZS EV | = 4.6 kWh/ (5×0.8) = 1.15 kW |
| Tata Tigor EV | = 5.3 kWh/ (5×0.8) = 1.325 kW |
| Hyundai Kona Electric | = 3 kWh/ (5×0.8) = 0.75 kW |
| Mahindra e2o Plus | = 3.5 kWh/ (5×0.8) = 0.875 kW |
Average panel size for Indian Electric Vehicles = (0.85 + 1.15 + 1.325 + 0.75 + 0.875)/5
= 1 kW
4 x 250 watts solar panels to charge the electrical vehicle when s/he has to fulfil her/her average travelling energy needs in India.
EV Payback
The average residential electricity price in India is Rs. 6.6 per unit.
And it is growing at a rate of 8% per year.
We found that a 1 kW EV charging system can provide enough energy to the battery to run 21.7 miles in a day.
A 1 kW system generates 4 units of electricity in a day.
That means you are saving 4 x 6.6 = Rs. 26.4 in a day
"This post contains affiliate link/s. It means that I may be compensated when you click on those links and buy the products (without any extra cost to you). However, I fully recommend these products when it comes to solar power."
In 1 year your solar savings = 26.4 x 365 = Rs. 9636
A 1 kW system can cost you around Rs. 70,000
On that basis, the payback is:
Payback = Rs. 70,000/Rs. 9636 = 7.3 years
Remember, solar panels are very durable.
They have a useful life of 25 to 30 years.
When payback is reached, thereafter you start making a profit on your invest
My solar feasibility spreadsheet sizes, designs, and finds the complete financial feasibility of the solar power system.
