Mark's
E-bike

My path to E-biking

Written by: Mark Gelbien

My dilemma: I wanted a way to ride my bike to work, save gas, be a good citizen of this planet by driving less and as an individual, reducing my C02 output. I also needed to arrive at work in a reasonable amount of time and get there sweat free. Well, riding a bicycle fast so as to arrive someplace in a reasonable amount of time and being sweat free are contradictory statements. My place of business has no showers or changing facilities so getting cleaned up after a bike ride to work was impossible.

I pondered this problem for several years. I loved cycling and rode for fitness most every day. Yet I was never able to get in good enough shape to average say eighteen miles per hour and not look like a sweat rag afterwards. Yet for me to travel the 9.5 miles to work in under 40 minutes I needed to achieve about eighteen miles per hour.

Once gasoline reached three dollars a gallon, I knew I had to come up with an alternative way to get to work. I thought of a motorcycle but in the congested suburbs of Long Island it was just too dangerous. The idea of using a bicycle never left my mind.

As a senior Engineer with Power supply, Motion control and motor systems experience including over 25 years of Medical systems experience, where I engineered both power systems for large MRI magnets and Motion control systems for sophisticated patient positioning tables, it dawned on me that I could contrive some way of power assisting a bicycle and still have the feel and safety of a bicycle. So before I ran off and started designing, I’ve learned its wise to research what’s been done to date. I Googled motor assisted bicycle and got hundreds of hits maybe thousands, and instantly knew this was the right path in my goal of cycling to work.

My research discovered that the Chinese have been working on perfecting the E-bike for several years and being a society that traveled mainly by bicycle they were longing for a way to make bicycle travel easier. For most people in China the car was not an affordable option, so the electrically assisted bicycle was an obvious solution. Once the engineers in China and the rest of the world started working on the design for a true a Hybrid bicycle, integrating man and machine into a single vehicle, there evolved a design that was completely quiet, assisted the rider, but didn’t take the feel of cycling away and included the need for the rider to contribute some pedaling effort. In China last year 20 million E-bikes were sold.

One of the best motor designs today is called a hub motor. This simple concept places the motor in the hub of the wheel eliminating the need for any connection to the pedaling drive train. With the front wheel being electric and the back wheel being human powered you wind up with an all wheel drive bicycle. Rear wheel human powered, front wheel electrically powered. This to me is the ideal design.

The motor can only perform if there is a power source. This is where battery technology and the E-bikes meet. Batteries have always been the weak spot in any electrically powered vehicle. In the least expensive E-bikes lead acid batteries are still being used. In my opinion “lead is dead” when it comes to E-bikes. They are just too heavy and don’t have the range. Luckily, Nickel Metal Hydrate is available and Lithium Ion batteries are becoming available. They may not be cheap but they are worth it.

Since a good long range battery wasn’t available, I used my experience in electrical engineering to design my own battery.

For my E-bike I designed a 120 cell LI-ION battery with a rating of 37 volts at 27AH.

This battery exceeds anything readily available and gives me a range of fifty miles or more. My design incorporates 10 circuit boards to control the charge/discharge and monitor the balance of the battery packs. LI-ION is a complicated chemistry to control but if done correctly you get a battery with incredible power in a light weight package. In fact, LI-ION cobalt batteries have the highest power to weight ratio of any commercial battery. Now with the advent of Lithium Iron phosphate batteries there is also an added level of safety while retaining most of the power to weight benefits of Lithium cobalt.

The future for E-bike looks great with better batteries and lighter motors, They will be part of the solution for a fun way to travel while using almost no energy (compared to cars, even electric cars) for short trips to friends in the neighborhood, people who live within 15 miles from work, shopping around town and going to dinner in that local restaurant. In fact for almost any trip that can be done on secondary roads, the E-bike is the perfect way to go.

So I challenge you to think outside the norm and give E-biking a try.