Comparing Efficiency, Ride Feel, Cost, and More: A Contrast between Series Hybrid Electric Bikes and Conventional E-Bikes!

Recently, the Mando Footloose series hybrid electric bike was announced, marking a significant shift in our perception of electric bikes. This innovative type of e-bike features an alternator at the cranks, which generates electricity through pedaling. The bike then utilizes this electricity, along with the power stored in the battery, to propel the motor. By doing so, it eliminates the need for traditional bicycle drivetrain components like chains, chainrings, cogs, derailleurs, and shifters. To delve deeper into the intricacies of a series hybrid e-bike, I recommend exploring the Mando Footloose for more detailed information.

A dear friend of mine, David Calley, who possesses exceptional technical knowledge, expressed great enthusiasm for this new breed of e-bike. He firmly believes that the efficiency of the series hybrid system surpasses that of conventional “parallel e-bikes.” Typically, parallel e-bikes consist of separate drivetrains for pedal power and electrical assistance, operating independently. However, the series hybrid brings both sources of energy together, forming a unified electrical system that powers the bike.

Now, let’s delve into David’s insightful thoughts on the efficiency, ride experience, cost, and maintenance of series hybrids when compared to direct drive hub motor e-bikes. Brace yourself for some technical content!

Comparing efficiency:

In this analysis, we compare a series hybrid hub motor e-bike to a direct drive hub motor e-bike. It’s important to note that this comparison focuses solely on direct drive hub motors, as geared motors introduce subjective factors that make the analysis less objective.

In both cases, there are shared electrical losses. The motor’s “core” losses remain constant, regardless of whether the motor is delivering power or not. Similarly, the electronics often remain powered on, as they need to be ready to provide additional power. Therefore, both types of e-bikes experience parasitic losses.

However, it’s crucial to recognize that all torque and power must originate from the motor itself. There is no separate chain path for torque and power to be added. Therefore, the motor must possess adequate torque and power capabilities, which may necessitate a motor capable of delivering higher torque.

Rest assured, the Mando Footloose series hybrid e-bike boasts remarkable performance, combining the best of electric and pedal power for an unparalleled riding experience. Its innovative design eliminates the complexities associated with traditional drivetrains while maximizing efficiency and enhancing overall performance. Explore the world of series hybrids and embark on a revolutionized e-biking journey!

Putting all the power, human and battery-generated, through the direct drive motor adds resistance losses, but not core losses. In simpler terms, if the motor only had core losses, its efficiency would increase because we would be dividing more power by the same losses.

If the motor doesn’t need to increase in torque and power because it’s already sufficient, resistance losses will increase, and core losses will decrease as a percentage.

In terms of electronics, the losses are similar in that they occur whether a small amount of power is flowing or if higher power is being delivered. So, essentially, only increased resistance losses occur. The efficiency of the electronics may rise or fall, but the effect should be minimal.

Now, let’s consider the losses in the chain drive. Many believe that bike gearing is almost perfectly efficient, but the truth is that it’s quite efficient and getting accurate information about it is difficult. I will have to search for sources to confirm this, but surprisingly, it’s not uncommon for bike gearing to have efficiency in the 80s.

Higher losses occur primarily due to two reasons. First, when the chain is unaligned. Experienced riders can minimize this, but less experienced riders might not be aware of the losses and wear caused by it. Second, a small gear (chain ring) diameter. These smaller gears are necessary for higher speeds, but they cause the chain to bend more at each link, resulting in higher losses. And just to address the inevitable question, I haven’t come across any research suggesting that lubrication has a measurable effect on efficiency.

With all that being said, the efficiency of a system will primarily depend on its design qualities. In my opinion, a cutting-edge series hybrid hub motor eBike can be designed to have better real-world efficiency than a parallel (chain drive) eBike.

Now, let’s delve into some more important aspects of this comparison.

Rider Feel:

The series hybrid rider won’t experience the same solid connection between the gear and the wheel as the parallel bike rider. It will feel more like the chain has been replaced by a bungee cord. However, this can be adjusted through software. That being said, the peak torques that a rider occasionally outputs are so high that it’s unlikely a designer would choose a large generator to accommodate them.

In a series hybrid, you can always be in the perfect “gear”. The programming can be set up so that the cadence always feels right and can be easily adjusted.

The rider’s output power can be higher or lower than what is required, giving them more control over how much energy they want to exert compared to what the path and wind dictate.

Costs:

At this point, the costs of traditional high-quality bike parts have been refined to very high levels. New types of equipment such as automatic shift systems start out as very expensive.

The series hybrid would be similar. For a higher torque bike where the motor is already sufficient, the costs may be very similar between a series hybrid and a chain hybrid.

In the long term, I wouldn’t expect to see a significant cost difference between them. However, it’s worth noting that eBikes are still relatively expensive compared to non-electric systems. The value of eBikes will steadily rise in the coming years.

Other Important Factors:

Less maintenance! There should be no need for maintenance for the drive. There is nothing to adjust or align. There’s no chain to stretch, and chain rings won’t wear or get damaged by rocks. Plus, there are no cables to the derailleurs to get gummed up, adjust, or replace. The motor and generator have no moving parts that can wear out.

 End of post by David Calley.

Comparing Series Hybrid to Parallel Electric Bikes

David brought up some noteworthy points when discussing the comparison between series hybrid and traditional “parallel” electric bikes. It is intriguing to observe how the series hybrid bikes perform in real-life scenarios, particularly after numerous riders have accumulated considerable mileage on them.

My Future E-bike Reviews

In the near future, I aspire to evaluate several of these innovative bikes and share my perspective on these fresh e-bike models.