What time of day is best for buying fuel or charging your EV?

If your business has a fleet of commercial vehicles, you’re always thinking about how to optimize fuel efficiency. It’s one of the most important considerations for improving your bottom line and ensuring smooth operations. Whether you operate a fleet of internal combustion engine (ICE) vehicles, electric vehicles (EVs), or a mixed-energy fleet, a key factor to maximizing fuel efficiency is strategically planning where drivers will fuel along their routes every day. Data compiled by WEX shows that there are optimal times of day to purchase fuel. There are also best times to charge EVs. This article is designed to help fleet managers reduce fuel costs and run company vehicles efficiently.

Your fleet: How to save money on fuel

If your business is looking to save money on fuel costs, using a fleet card paired with a telematics solution will set you on the right path. For one thing, with the use of mobile apps and GPS fleet tracking, your drivers can find the most affordable fueling stations along any given route. You can also take the savings one step further by scheduling where a driver refuels along the route in advance. Instead of the driver searching for the lowest prices while en route, fleet managers can plan ahead. This means finding the most affordable fueling location, as well as the best day of the week and time of the day to refuel. Prices at the pump change throughout the day and throughout the week.

Just like when refueling your ICE vehicle, there are optimal times to charge EVs. For mixed-energy fleets that operate electric or hybrid vehicles, you should create best practices to maximize battery efficiency. With charging and refueling best practices you can help your company save money.

When should you fuel your fleet?

Whether your drivers travel hundreds of miles a day or stay local, you can still save money at the pump. You don’t need to have the most recent vehicle make or model to achieve better fuel efficiency either. The way your fleets are driven, and how they’re fueled and maintained, impact getting the most out of fueling costs.

Fuel in cooler weather

The best time to refuel your vehicle is when the weather is cool. Fuel expands and contracts depending on the temperature out, so the volume of fuel in your tank can vary depending on the time of day and time of year.

Another consideration related to temperature, is that all service stations store their fuel in underground tanks. When the temperature is cooler, fuel is denser and takes up less space. This means that when you fill up your tank early in the morning or late at night, you’re getting more fuel for your money. On the other hand, when the temperature is warmer, fuel expands and takes up more space, which means that you may be getting slightly less fuel when you fill up during the hotter hours of the day. In the long run, fueling timing can have a $0.10 difference per gallon for your fleet, making a significant impact on annual fuel expenses.

Best time of day to fuel:

• Fuel your fleet early in the morning
  • Data from the past four years shows fuel prices are traditionally lowest between 7 AM and 8 AM. Not only is this a peak commuter hour, so more people are purchasing fuel, but the temperature is cooler in the morning. This is an optimal time to fuel your fleet because the prices are cheaper and the temperatures are typically cooler than they are in the middle of the day.
• Fuel your fleet late at night
  • Similar to the early morning, temperatures are cooler in the evening. This time is also optimal for drivers and fleets avoiding wait times at the pump during peak business hours.

Best days of the week to fuel your vehicles

Prices are inconsistent throughout the week. For instance, people tend to travel on the weekends, therefore more fuel is likely to be purchased during weekend days. Fueling stations will likely increase the price of fuel on Fridays, Saturdays, and Sundays to make a higher profit. This means weekends are not the most cost-effective time to purchase fuel. Instead, try purchasing fuel earlier in the week (Mondays, Tuesdays, and Wednesdays) when you can.

Tips to help your fleet save on fuel

Don’t wait until you’re on empty to fuel up

When it comes to maximizing fuel efficiency, there are several strategies beyond timing when you fill up. Another important, science-backed tip is to avoid waiting until your tank is empty before refueling. Fuel can evaporate when exposed to air, which is why the fuel storage tanks are designed with floating roofs to reduce contact with the atmosphere. This means that driving a vehicle with a nearly empty tank makes the remaining fuel evaporate more quickly. Filling your tank before it’s empty ensures that you always have reserve fuel available and reduces the risk of running out. The recommendation is to refill the tank once there is a quarter of a tank remaining.

Fill up your tank all the way and slowly when you fuel your fleet of vehicles

To further optimize fuel usage, drivers should fill their tanks all the way up whenever they’re pumping fuel. This ensures that your drivers are maximizing range and minimizing the number of refueling stops. Additionally, remind your drivers to fill their tanks up slowly when possible to reduce the amount of fuel vapor lost during the fueling process – every drop counts!

Obey the speed limit: it conserves fuel!

Another effective way to save money at the pump is by maintaining a consistent pace and adhering to the speed limit. According to the US Department of Energy, each 5 MPH you drive over 50 is like paying 14 cents more per gallon of fuel. By avoiding unnecessary acceleration and quick decelerations, maintaining a steady speed can improve vehicle fuel efficiency as well. According to the U.S. Department of Energy, obeying the speed limit, accelerating and braking gently and gradually, and reading the road ahead can improve the fuel economy of your vehicle by 15%–30% at highway speeds and 10%–40% in stop-and-go traffic.

Keep tires inflated

Lastly, it is important to remember the impact properly inflated tires can have on miles per gallon and overall fuel efficiency. Keeping your tires inflated to the vehicle’s recommended pressure results in better fuel economy. According to the U.S. Department of Energy, maintaining the appropriate tire pressure enhances fuel efficiency. They estimate that properly inflated tires may boost mileage by as much as 3.3%. Conversely, for each 1-psi drop in pressure, under-inflated tires can potentially reduce fuel mileage by 0.3%. This is a simple yet effective way to enhance fleet vehicle performance. By doing so, you ensure you’re achieving the maximum miles per gallon. This is another reminder on the importance of regular maintenance checks for fleet vehicles.

Best times to charge your fleet of EVs

The refueling procedure is different for an EV than it is for an ICE vehicle. With a shift toward more EVs on the road, fleets need to assess their fueling practices. Ideally, you’ll implement strategic route planning to create charging efficiencies for the EVs in your fleet. One way to go about it is by crafting routes to include public charging stations. According to the U.S. Department of Energy, public direct-current fast-charging (DCFC) stations are increasingly accessible along major transportation corridors. This allows EVs to extend their range and provides convenient charging options. Parking at these public charging stations while at work allows drivers to optimize fuel efficiency. If you have your drivers charge during scheduled stops, your can minimize idle time and build efficiencies.

The optimal time to charge an EV is at night when the vehicle is not in use. By charging vehicles overnight, you also take advantage of off-peak electricity rates. Your drivers also can then start each morning with a fully charged battery. This can be done at the driver’s home or in a charging facility. Depending on the range of your EVs and their daily mileage, a full charge in the morning may be sufficient to meet your fleet’s routes for the entire day. This eliminating the need for further charging until back at home again at the end of the day.

Tips to save money when charging EVs

When it comes to charging your electric fleet, there are best practices that can help you save money and maximize efficiency. A simple technique to implement with your drivers is regenerative braking. This is a feature not shared with ICE vehicles. It allows energy recapturing while on the road.  Electric vehicles are equipped with regenerative braking systems. They allow vehicles to recover and store energy generated during braking or deceleration. Research done by J.D. Power shows that by employing regenerative braking, the vehicle’s electric motor can decelerate the car while capturing and redirecting up to 70% of the energy that would typically dissipate. This energy is then channeled back into the battery for recharging purposes.

Another consideration for battery powered electric vehicles is the 80/20 rule. Think of it as similar to the smartphone battery charging best practices we’ve known about for years. Essentially, an EV’s battery will last longer if you prevent it from charging 100% or running the battery down to zero. Adhering to the 80/20 rule means not charging your EVs past 80% capacity and not letting your charge go below 20%. By maintaining this range of charging, the longevity and efficiency of your EV batteries is increased. Most EV have touch screens where drivers can select the specific desired charge level when you’re plugging in overnight.

80/20 rule for EVs depending on the vehicle

However, the 80/20 rule may not apply to every vehicle or situation. Some EVs may recommend charging the battery to 100%. Or drivers may need the full charge for more range during longer routes. This is entirely dependent on how each fleet business operates, and the make-up of the fleet.

Lastly, when considering the charging infrastructure for your fleet, you should assess the specific needs of your vehicles. Different types of EVs may require different charging options. These include Level 1 charging (using a standard household outlet), Level 2 charging (using dedicated charging stations), or even DC fast-charging for quick top-ups. By ensuring that the charging infrastructure matches the requirements of your fleet, you can:

• streamline the charging process
• minimize downtime
• optimize efficiency.

Increase fleet efficiency with a strategic fueling plan

You can use the information we’ve provided for route planning, optimizing fuel expenses, and improving the efficiency of your fleet. By implementing these tips and techniques, you should be able to:

• save money on fuel
• extend the lifespan of your batteries
• reduce charging times
• enhance the overall fuel efficiency of your fleet.

Embrace these strategies and watch your fleet’s efficiency soar, leading to cost savings and greener, more sustainable operations.

To learn more about WEX, a dynamic and nimble global organization, please visit our About WEX page.

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Sources:
US Department of Energy
J.D. Power
Fuel Economy
Ok Carz

Editorial note: This article was originally published on July 11, 2023, and has been updated for this publication.