BEVs vs PHEVs For Towing – Pros and Cons


Me
Hi, I’m Chris. About Me

While the aim of this website is to mainly promote battery electric vehicles (BEVs) when it comes to towing I still think there is a place for certain plug-in hybrid electric vehicles (PHEVs) for several years to come. So with this article, I want to explain why I think that’s the case but also why ultimately pure battery electric vehicles will be the best solution not only for the planet but also for towing. Therefore below I’ve produced a pros and cons of BEV vs PHEV tow cars based on current technology/infrastructure.

BEVs vs PHEVs
So when it comes to towing how does a BEV (left) currently compare against a PHEV (right)? : Images – Tesla.com & BMW.com

What’s The Distinction Between a BEV and PHEV?

A BEV (Battery Electric Vehicle) is where the source of energy/power is purely from batteries/electric motors. There is no combustion engine within the vehicle.

The only source of energy is electricity via a plug, maybe a charging pad in the future. A typical example when it comes to BEV tow cars would be a Tesla Model Y.

A PHEV (Plug-in Hybrid Electric Vehicle) does have a battery and an electric motor, however, they are only supplementary to the main source of energy/power, an internal combustion engine. Importantly though, a PHEV can take on electrical energy directly via a plug, unlike a standard hybrid.

Therefore, for some journeys its possible to run a PHEV only on electricity which was not sourced from the combustion of fuel. A typical example when it comes to PHEV tow cars would be a BMW X5 45e.

Battery Electric Vehicles (BEVs) Pros and Cons

First, we’re going to look at BEVs and discuss their pros but also their cons. However, its important to note, this article is discussing the pros and cons of BEVs as a tow car, not just as a car in general.

For someone who never tows a trailer/RV, I believe it would be a much simpler article. From this point forward if you can afford a BEV its already the best option for many people needs. When it comes to towing though, for at least the next couple of years its a much more complicated decision.

Pro – Good Power But Great Torque

When it comes to towing you are in some cases pulling as much as the car weighs behind you. Therefore, performance is going to take a hit and you want enough power and torque to be able to pull away and accelerate safely.

For instance, when joining the freeway to join safely you have to match the speed of the traffic. Therefore, in an underpowered tow car, that experience can be pretty stressful.

Jason explains why electric torque is a key feature, one which is also great for towing

Well, one of the benefits of an electric car is they are typically fitted with an electric motor that will provide more power and especially more torque than a typical petrol/diesel tow car.

Torque (pulling power) is where electric motors shine in particular, as they produce peak torque from 0 RPM. To explain this in comparison to internal combustion engines I’ve included the video above from Engineering Explained.

Pro – Electric Tow Cars Are Heavy (Stable Towing)

Currently, when you take two cars of a similar size and one is a BEV and the other is an internal combustion engine (ICE) car, the BEV will be significantly heavier.

Take for example a Toyota RAV4 with an internal combustion engine, that will typically weigh around 3,300 lbs. Well, a BEV such as the Tesla Model Y which is roughly the same size weighs closer to 4,400 lbs.

An electric cars battery pack is a large percentage of the weight of the car and its low down under the floor

When it comes to electric tow car efficiency, yes, more weight is not a good thing. However, when it comes to towing typically an electric car (due to the battery) being heavier provides a more stable towing experience.

In the simplest terms, with a heavier car, you get less chance of the tail (trailer/RV) wagging the dog (car) when travelling at speed along a fast road/freeway.

Furthermore, the majority of the weight in an electric car (the battery) is low down under the floor of the vehicle. Hence, the centre of gravity is also low down which is a further aid to stable towing.

Pro – More Storage Space In Electric Cars

I run a small RV site, so I get to see how much stuff people bring with them. In many cases, the tow car will be packed inside up to the roof. Hence, with a tow car its not only the towing capacity that matters but how much storage space the car has.

When you have an electric car that has been designed from the chassis up as an EV you get more storage space than ICE cars. As above, let’s discuss the examples of a 2021 Toyota RAV4 and a 2021 Tesla Model Y.

The Tesla Model Y has a trunk, under trunk storage and a Frunk

The RAV4 has a total cargo capacity of just under 70 ft³ with the seats folding down. What is the total cargo capacity of the Telsa Model Y… 76 ft³ How is it possible to get an additional 6 ft³ of cargo volume from two similarly sized vehicles?

The reason the Tesla Model Y as an example provides so much more cargo volume is because it has additional storage areas, there is an additional storage area under the floor in the trunk and there is also storage under the hood, the frunk.

Pro – Fewer Parts & Less Brake Wear

As fully electric cars have fewer components and fewer moving parts there is simply less for there to go wrong and fewer components that may need to be changed down the road.

What about the battery? Well, we are now at the point with current battery chemistry and batter thermal management that the rest of the car will be worn out before the battery needs replacing in most cases.

With an ICE car, clutch wear is accelerated when towing and there is a myriad of components that can go wrong. For instance, to make modern ICE cars comply with the latest emissions regulations there are more particulate filters and catalytic converters than ever before.

A quick 3 min explanation of how regenerative braking works and how it reduces brake wear

Furthermore, when it comes to brakes, an electric car has regenerative braking which reduces brake wear. When towing the brakes are obviously put under additional force and last a shorter period of time.

I will note though, tyre wear on electric cars can be more than on ICE cars. Partly due to the additional weight of electric cars as referenced above, but also due to the higher torque output of the electric motors.

Con – Range Reduction When Towing

Electric car development is now getting close to the point where when not towing ‘range anxiety is becoming less of an issue. Partly due to the increased range of modern electric cars but also due to the continued expansion of the DC rapid charging networks.

However, towing with an electric car is a whole different ball game and typically results in a 50% range reduction compared to the typical range the car achieves when not towing.

EV Range Reduction While Towing
Put an RV/trailer on the back of an EV and you should expect a significant reduction in range: Image – Elbil.no

Though, the 50% range reduction is a very general rule. In the worst-case scenario pulling a trailer/RV with poor aerodynamics up a hill at speed in cold weather and into a headwind, the range reduction would be much more significant.

Therefore, for quite a few years to come ‘range anxiety while towing in an EV could very well be a legitimate concern. It also leads to the other two associated issues below.

Con – Rapid Charging Time & Frequency

As the range of an electric car is reduced significantly when towing and a 50% range reduction at least should be expected it means DC rapid charging will be needed twice as frequently compared to an EV not towing.

As I discuss in my article on the fastest charging electric tow cars, currently the fastest charging EVs can go from 10% to 80% state of charge in 17 minutes. However, that’s under ideal conditions and only when plugged into a DC rapid charger that matches or exceeds the charging speed of the car.

An excellent video guide to the current status of US rapid charging networks

In general with current electric car technology to get from 10% to 80% you should expect a DC rapid charging time between 30 to 60 minutes. Past an 80% state of charge pretty much all electric cars charge very slowly. Hence it doesn’t normally make sense to use a rapid charger to get between 80% and 100% state of charge.

With a significant range reduction while towing in an EV and the need to use DC rapid chargers more frequently for a 30 to 60 minute period this leads us onto the third issue.

Con – Few DC Rapid Chargers Suitable For Electric Cars Towing

So this issue is not to do with the number of DC rapid chargers or the rated power of available chargers, this issue is related to the size of charging spaces and access for electric cars towing a trailer/RV.

Currently, there are very few (and I mean very few) pull through DC rapid charging spaces in the US. Hence, a charging bay where you can leave the trailer/RV attached to the electric car and charge at the same time.

Issues Charging While Towing
This issue of charging while towing and a lack of pull-through charging bays needs to be addressed: Image – TFLtruck.com

Therefore, that obviously means to DC rapid charge currently you would have to uncouple the trailer/caravan and drive the electric car over to a rapid charger, not convenient by any means, but there is a second issue.

The most likely scenario when you would need a DC rapid charger is at freeway services. While there is a growing number of rapid chargers at freeway service stations around the US can an electric tow car actually get to them?

Cars towing a trailer/RV often have a separate parking area at freeway services, typically the truck park. Well, currently the vast majority of DC rapid charges are only in the car parking area…

Plug-in Hybrid Electric Vehicles (PHEVs) Pros and Cons

So now let’s discuss the pros and cons of PHEVs as electric tow cars. Please note, I believe for those who don’t need or intend to tow a trailer/caravan from this point forward a BEV is the better option in most cases.

However, as shown above, when it comes to towing we are still transitioning to a BEV being the obvious best option. Therefore, is a PHEV the best of both worlds?

Pro – Quick Refueling With Good Access

Again, this is specifically from the perspective of towing. Hence, when you use the most energy towing is travelling at speed, on the motorway for instance.

With a PHEV as it still has its onboard internal combustion engine you can just pull through the gas station, fill up in a few minutes and you’re on your way.

Gas Station
Currently, the time to refuel with gas/diesel is significantly faster than to recharge an electric vehicle for the same mileage

An internal combustion engine, just like a battery/electric motor will typically consume twice the normal amount of energy when towing. Hence, an ICE car will see a significant reduction in MPG when towing.

While the additional fuel costs are obviously observed by the user the difference in the time to refuel is not really noted as the speed at which liquid petroleum/diesel can be added to the tank is so fast.

Pro – Not Towing Electric Only Journeys

With certain PHEVs that have a battery of sufficient capacity when not towing, hence more likely most of the vehicles usable life, you can drive around on electric energy alone for most journeys.

Now, that only makes sense for the planet and your pocket if you actually plug in a PHEV to an electrical socket to charge the battery. That way the vehicle can be propelled by energy not sourced from burning fossil fuels, provided the source of energy is renewable of course.

PHEV Charging
A PHEV with a practical range that is regularly plugged in should be able to drive on electrical energy alone for most journeys

On this website, I’m only going to discuss PHEVs which have an electric-only range of around 50 miles or more. The Toyota RAV4 Prime has an EPA rated EV range of around 42 miles, but can get close to 50 miles at purely low-speed town driving.

Around 30 miles is often quoted as the average US commute, so why will I only promote PHEVs which provide a quoted range of around 50 miles? Well, as with any battery-electric vehicle, the quoted figure and real-world range are not the same, and I’ll get into this in a future article.

Con – Worse MPG Figures Towing Than Standard ICE Cars

How can that possibly be? To use the example again of the RAV4 Prime that’s given an official rating of 94 MPGe. Remember, we’re specifically talking about towing, and when towing, the battery/electric motor in a PHEV is more of a hindrance than a benefit when it comes to efficiency/economy.

The RAV4 Prime has a pretty substantial 18.1kWh battery by typical PHEV standards, hence why it currently has one of the highest pure EV ranges at 42 miles of available PHEVs. Well, under towing conditions using electrical energy alone, chop that distance in half, so 21 miles.

PHEV MPG Figures
Under towing conditions, the pure EV range is cut in half and after that point, the weight of the trailer will result in an efficiency figure well under 38 MPG: Image – Fueleconomy.gov

Hence, when towing on the freeway for instance the energy within the battery is insignificant. However, you are still carrying around the weight of that battery and electric motor, leading to reduced efficiency/economy compared to the standard ICE variant.

For instance, the RAV4 Prime with its 18.1kWh battery, electric motor and petrol engine weighs 4,300 lbs. The standard RAV4 with a non-hybrid gas engine weighs 3,655 lbs. Hence, with the Prime and an empty battery not contributing to propulsion the car is carrying around an additional 645 lbs of weight.

Con – Accelerated Battery Degradation

BEVs and PHEVs both suffer from battery degradation which basically means over time the capacity of the battery is reduced, hence the vehicle will cover fewer miles as the battery holds less energy.

However, a PHEV will typically experience more rapid battery degradation than a BEV because of the use case as battery degradation is mainly due to charging to 100% and discharging to 0%.

PHEV Battery Degradation
PHEVs general suffer from accelerated battery degradation/loss of capacity compared to BEVs: Image – CircuitDigest.com

With a BEV in many cases its possible to use the vehicle without charging to 100%, and you obviously would never intentional discharge to 0% as you would become stranded.

However, with a PHEV the battery is commonly charged to 100% and completely discharged to make the whole purpose of a PHEV viable. The downside though is with current battery chemistry this frequent 100% to 0% pattern leads to accelerated battery degradation compared to a typical BEV.

Conclusions On BEVs vs PHEVs For Towing

So what can you take away from the above pros and cons for BEVs and PHEVs for towing based on current technology/infrastructure? Well, currently for towing over short journeys (up to 100 miles say) there are already several BEVs that can do the job, and do it well.

A current issue with BEVs towing (and this will change) is due to the significant reduction in range when towing at speed the additional time added onto the journey for rapid charging is considerable when towing on longer journeys.

However, the bigger issue is the existing rapid charging infrastructure, not necessarily the number of rapid chargers but the layout of charging spaces which are not set up for electric vehicles with a trailer/RV in tow.

So is a PHEV the answer and the best of both worlds? No, not really, a PHEV is a compromised vehicle as discussed above which when towing outside of the vehicles battery range will be less efficient than a standard ICE car.

However, a PHEV could be viewed for the moment as a necessary evil if you need a car for towing over 100 miles. Though when not towing on normal everyday driving distances its vital the PHEV is plugged into charge, otherwise a PHEV makes absolutely no sense at all.

Chris

Hi, I’m Chris. I own and write all the content on ElectricTowCars.com. The content above is purely my own personal thoughts/opinions/research and should not be treated as professional advice. I hope you find the content above useful to help you find your future ideal electric tow car or truck.

Recent Posts