The Battery & Range

There has been a great battery evolution over the past few years. We tested various types of different cells and battery management systems and after many trials we choose the one. The latest technology cylindrical lithium polymer cells offer outstanding performance in conjunction with very good lifetime.

What Range can I get out of my battery?

• Pedal Assist Mode - up to 70 miles
• Throttle only - approx 32 miles
• Combined average - 50 miles

 

 

Why Cylindrical lithium polymer cells?

We use cylindrical because they are capable in delivering a higher current for longer comparing with the flat pack cells. Cylindrical cells also provide a greater heat release, the micro gaps between cells in the pack work just like tunnels where the heat can be distributed to the alloy case. This way our battery packs do not overheat as easily as the traditional flat packs which results

The tech-e stuff

Our 37V 15Ah battery pack is built of the 70 cells. Each cell is rated at 3.7V and offers a capacity of 2200mAh. In total there are 10 groups of 7 cells which connected in series give us 37V of nominal voltage. We also found that many cells in group work better than just one large cell.

The BMS (Battery Management System) and the o2 Microchip

In order to achieve the maximum performance and life time of the battery pack the cells need to be managed by the internal computer system called BMS (Battery Management System). The main purpose of the BLS is to control the work of each group of cells and ensuring that each group delivers the same current and keep same voltage and the charge level. Our battery packs are managed by o2 Microchip. This sophisticated battery management system ensures that the voltage between each group stays at the same level. For workshop purposes o2 Micro also enables full diagnostics of the battery making the communication and maintenance a lot easier.

What is the lifecycle of the battery pack?

Typically the battery lifecycle varies and there are number of factors which can affect the lifecycle. Usually the battery can last for 500-700 recharge cycles. In some extreme cases it can achieve even a 1000 cycles however by being more realistic we try to give more realistic figures.

WARNING: There may be battery manufacturers which may claim the lifecycle of even 2000 recharge cycles (for LiFePO4 cells). Having had several years of experience with various types of batteries and manufacturers we learned that even the best battery packs can not achieve those figures. The quoted lifecycle of 2000 recharges can apply to the single cell only and not a group of cells. It has been tested by our partner company DLG that single cell achieve a lot longer lifecycle comparing to the same cells being built up in pack.

Why use Lithium Polymer and not LiFePO4?

Lithium Polymer cells currently offer the best ratio of power density to the weight and achievable lifecycles. Few years ago the best promises were made with LiFePo4 cells (Lithium Iron Phosphate) as there were promises of the extremely long life ranging even 2000 recharge cycles. As mentioned above LifePo4 turned out to be very effective only when used as a single cell. When connected in groups the achievable lifecycle is very comparable with Lithium Polymer cells. LiFePo4 however have many other disadvantages of such as weight and lower power density. On electric bikes it is crucial to keep the minimal weight and achieve maximum range possible. This is why LiFePo4 is not as suitable for electric bikes. In electric bikes with LiFePo4 will always be heavier and offer a shorter range than the bikes powered by Lithium Polymer cells.

 

The Motor

8FUN by Suzhou Bafang is a clear excellence in hub motors. These motors have external rotor permanent magnet brushless construction, a planetary gear-reducer system and one-way overstep clutch are mounted on the same shaft, the torque is transferred by the hub inner gear ring on the hub to the hub directly. The main advantage of the 8FUN motors is the brushless design which does not contain brushes. Unlike some other basic motors the new brushless design does not require maintenance. The hub design is small and lightweight and weights only 2.8kg. Hub motor offers excellent starting performance with no magnet hysteresis damping energy and good creeping slop capacity.

Other advantages of these motors include:

• High efficiency with lower power consumption
• High starting and peak power of up to 572 Watts and steeples speed regulation
• No spark, no electric interference and explosion prevention
• Superior water-proof design.

Fun motors are widely used by many top quality electric bike manufacturers. Over the past few years the company has gained an excellent reputation for quality, efficiency and reliability. These are the reasons why Oxygen Bikes is delighted to use these motors in our range of bikes.  

 

Some of the above information has been taken from the 8FUN official website (source: www.szbaf.com)

SCT stands for Sport City Touring. It’s frame geometry which combines three types of riding positions in just one frame. Before we created our frame we have carefully analysed many types of frames. Based on the experience of our staff who all are active cyclists we have choose the best combinations between tubes angles and lengths to select the most ergonomic and optimal riding position. With SCT you still remain effective cyclist while you can still enjoy one of the most comfortable riding. With SCT you can forget about the back pain and the use of our super wide 690mm handlebars allow you to breath as easily as never before. While choosing the bike we understand what is the most important for the cyclists. Having had a years of experience in riding different sorts of bikes we come up with the geometry design that will bring you loads of fun and comfortable ride. Oxygen Bicycles have been created by cyclists for cyclists this is why believe in the excellence of our bikes.  

Our Alpha Alloy frame

Alpha 7005 is the frame technology which delivers the superlight, rigid frames for our Oxygen Electric Bikes. All our frames are made of alloy mix containing a mix of aluminium 7005 and magnesium. The 7005 alloy delivers a super lightweight frames with the maximum strength which is crucial to achieve the maximum reliability. Additionally every frame is hand welded to ensure the highest quality of welds.

What's the max and min riders height?

Oxygen Emate frame size is 19''. This size can accomodate majority of people who are between 5'7'' and 6'4'' high. For those who are shorter or taller than the recommended height the frames can still be individually adjusted by adopting different stem length.