EDITORS DESK

For many internal combustion engine (ICE) vehicle drivers, the km/L reading of a car has become the standard by which we measure its efficiency. By just attaining this figure, it’s quite easy to calculate how much you’ll be spending on fuel in a week or month, and hence how much out of the household budget to set aside for transportation costs.

When it comes to battery electric vehicles (BEVs), it’s a different way of computing efficiency, and also a radical change in how it is refueled. It is plugged in, rather than refueled, and unlike cars, recharging takes hours instead of minutes.

To help you decide on whether it is the more efficient mode of transportation and worth the sacrifices, we’ll share how to compute its efficiency, and by extension how much you can expect to pay your electricity provider to recharge the vehicle.

AAP x BYD efficiency run

For this exercise, it’s important to make a few assumptions. First of all, let’s assume the cars are only recharged in one’s home. Second, it’s important to know your electricity provider’s power production rate (which changes every month). Based on Meralco’s most recent rates (May 2024), the power rate this month is ₱12.60 per kilowatt hour (kWh). Thankfully, the battery size and capacity of EV’s are already in kWh to make this computation easier.

Finally, our EV efficiency readings will be based on the recent fuel efficiency test conducted by the Automotive Association of the Philippines (AAP) with BYD vehicles just last month. The test was conducted to log credible and verifiable driving efficiency data from the BYD Atto 3 and Dolphin under mixed highway and city conditions.

This is a safe benchmark as the test was conducted with both small and large EVs driving within Metro Manila and even out to Alabang on a weekday. After all, small EVs are light and have small batteries, while larger EVs boast of longer range, but are also heavier, which may factor into their efficiency. These results can also give a glimpse of how similarly sized competitors — like an MG4, Nissan LEAF, Hyundai Ioniq 5, Kia EV6, or MB EQB — will compare.

For further accuracy, the test took readings from four of each kind (small and large) of EV to get a better average. Climate control, tire pressure, and various other factors were put to a fixed setting for all vehicles. Finally, an AAP staff member was riding along in each car to ensure the vehicles were driven in a regular manner rather than conscious energy efficient manner. Vehicles were also tested using various driving modes (Eco vs. Sport mode, default vs. high regeneration) to get a broader spread of results.

Km/L vs km/kWh

We’ll spare you the long analysis and skip straight to the results (based on highest consumption) to give you a more realistic picture of how they fare. The key figure to know here is km/kWh. This helps you calculate the actual range you can get out of the EV’s battery. Like regular ICE cars, this figure can also change depending on city or highway driving. Like in ICE cars where you multiply the reading by the capacity of the tank (e.g. 8-km/L x 40-liters = 320-km) to get the driving range, you can multiply this figure by the size of the battery, (e.g. 5-km/kWh x 60-kWh battery = 300-km) to get the real-world range.

The efficiency figure

The BYD Dolphin, a small EV the size of a Honda Jazz or Toyota Yaris, logged a highest figure of 4.71 km/kWH in the city and 8.27 km/kWH in the highway. The BYD Atto3, a mid-size EV the size of a Honda CR-V or Hyundai Tucson, logged its highest reading of 3.77 km/kWh in the city and 8.45 km/kWh in the highway. This can easily be compared to ICE cars which get (on average) 8 km/L in the city and 12 km/L in the highway.

With these figures, you can now calculate how much you can expect to pay in energy rates depending on how far you drive. Let’s assume the average person living within Metro Manila drives 14-km one-way from their home to office. Thus, he travels 28-km a day, 140-km a week, and 320-km a month. Assuming he lives in Alabang, that would roughly be 60-km a day, 300-km a week, and 1,200-km a month.

Divide those distances by the km/kWH reading and multiply by the electricity rate (₱12.60 per kWh) and you get the cost per distance travelled. Similarly, you can also divide the distance by an ICE vehicle’s km/L reading and multiply that by the cost per liter (whether gasoline or diesel) to get a comparative result.

Sparing you the complicated math, a small EV like the BYD Dolphin can cost you around ₱375 a week, or ₱1,500 a month in energy costs. These costs are lower if there’s more highway driving. A larger EV like the Atto 3 will cost around ₱470 a week to ₱1,900 a month. You’re likely familiar with ICE costs already, amounting to ₱1,500 a week to ₱5,700 a month in fuel if you drive a diesel or as much as ₱1,600 a week to ₱6,300 a month if you drive a gasoline-powered car.

Granted, the one final factor to consider is the higher acquisition cost of EVs and its basic requirements. A BYD Dolphin costs around ₱1.4 million whereas a similarly-sized ICE car may be just ₱1 million to ₱1.3 million. A BYD Atto3 is ₱1.8 million while a similarly sized ICE SUV may be around ₱1.5 million. Furthermore, to charge at home, you will need a high-capacity power outlet to plug the charger into. Still, these are differences that may be made up for in savings, particularly if the vehicles are driven daily.

We hope this little formula will help you make a more informed decision, particularly when it comes to making the switch to more sustainable transportation.