Empowering E-Bikes: Bike to E-Bike Conversion

BBS01 System

The BBS01 system is simple to operate and ride as follows. The system may be provided with a selection of different displays, and Empowering E-Bikes can provide the appropriate manual with full details of operation and programming options for each one. However, in each case, the controller is linked to a separate 3 or 5 button unit that controls the system. The system is turned on by an extended press of the central button, and turned off likewise.

The system has a key variable referred to as PAS (Pedal Assist System) which is shown on the display unit. Despite its name, this variable is applied to the motor whether the motor is operated by the throttle or by the pedals. It is a rotational speed (rpm) setting for the motor, from 0 (motor is effectively disabled) up to the maximum level. Depending on how the system is set up, it can display from 0-3 up to 0-9 (although in all cases 0 represents 0% and the maximum number of the range represents 100%, with the intermediate numbers spaced accordingly). The '+' (or up arrow) will increase, and the '-' (or down arrow) will decrease it. When the motor is turned on, this variable always defaults to 1.

It is important to note that the maximum number in the range corresponds to the optimum motor speed. Therefore, generally, the PAS setting should be adjusted to maximum unless there is a specific safety reason not to (and note that setting PAS to 0 effectively disables the motor without switching the system off).

Other display items and functions include

Speed in km or miles per hr
Odometer
Battery indicator, showing remaining battery charge by a series of bars. Note that the battery is mostly empty by 2 / 1 bars remaining.
On some models the battery voltage is displayed. This is the best indicator of remaining battery charge.
USB outlet for charging mobile phones (On the 850C model only)

When riding, the system can be operated by i) the throttle or ii) the automatic pedal assist that will operates the motor automatically whenever the pedals are turned. Turning the pedals will operate the motor even if the rider is not actually pushing; the system senses movement of the pedals not force. The pedal sensing system will typically be programmed with a lower maximum power output, while the throttle will progressively provide up to 100% power. To ride the system most efficiently therefore (i.e. to maximise range) the pedal assist can be used as a steady, continuous but moderate boost to pedaling, with the throttle being used when necessary to top up the power (for example to keep up full speed on hills).

General considerations and best practice include

There is generally a small delay in activation of the throttle if the pedal system is activated and vice versa; to minimise this the E-brake can be pulled very slightly to cut out the motor ready for the throttle to engage. It is also good practice to do this (or at least release the throttle) when changing gears (gears will generally shift under full power, but this may accelerate wear on the chain).
When not using the bike, it is good practice to switch it off
Never touch the chain when the motor is switched on, as getting a hand caught between the driven chain and the gear teeth could cause serious injury
With thumb throttles, ensure that nothing gets in the way of the full movement range of the trigger which might catch when operated
Mid drive systems put high power through the bike chain system, therefore the rider should be aware of and follow best practice with regard to bike chains. Firstly, the bike chain should be checked for wear on a regular basis, and replaced before an excessively worn chain starts to wear other (more expensive) components. A chain wear tool can be provided and is simple to use. Secondly, chains should be kept clean and well lubricated.
The motor system has a high degree of water resistance, but should be dried off as soon as possible after use in the rain and actual immersion in water avoided.

When riding a mid drive bike, full use should be made of the bike gears to ensure that the benefits of the mid drive can be realised. As with any system, motor life will be prolonged by not running maximum power continuously. However, on hills it will be best to apply as much power as is needed to get up the hill at a 'reasonable' speed. To reiterate; on the Bafang mid drive system the 'PAS' level is not a power setting, but instead sets the motor speed, and it should be kept high to keep the motor at optimum performance. Therefore, hills should never be tackled in low PAS level / high gear, which is a recipe to burn out the motor, but instead in high PAS level and a gear as low as needed to keep up full speed for that gear.

While this will quickly become intuitive, a good test of whether the motor is comfortable is that if you change up a gear then the bike should speed up; if it does not then the motor does not have enough power for the faster speed of the higher gear and you should change back down. In other words you should avoid riding in such a way that the motor does not have enough power to reach its full speed, and whenever you find that it is not able to do this you should change down a gear.

While this is less important if the bike is being ridden on the flat, arguably it will almost always be better to set a high PAS level; if this causes the bike to pull away too quickly for safety then it is better to choose a lower gear than to reduce the PAS level. If there is no lower gear then it may be useful to considering changing the gearing in any case to enhance hill climbing; alternatively, PAS 0 can be selected or the motor switched off when power is not required.

Gear Range

With regard to designing and riding a bike with a mid drive unit, the primary consideration is the gear range of the bike, and ensuring use of the optimum gear at all times. This should always be a consideration for an electric bike, since the ride be will less effective and less satisfying if there is not an appropriate gear for the rider to pedal efficiently at the required speeds. However, for a mid drive system, the gearing of the bike is effectively a part of the motor system and therefore requires special consideration. The mid drive is effectively operating in the same way as the rider turning the pedals of the bike i.e.

When a low gear is selected, the mid drive will propel the bike slowly but have high torque and be able to climb hills effectively
When a high gear is selected the drive can propel the bike at higher speed, but will have low torque and therefore not be able to propel the bike uphill

Since both these characteristics may be required, a wide gear range is useful, exactly as on a normal bike. However, compared to an un-powered bike, the gear spacing is less important. On the un-powered bike the rider will want to ride with optimum pedaling rate (cadence) and optimum input power, so needs a good gear match and hence close gear spacing. On the electric bike a variable amount of power can be taken from the motor to keep up the speed, so big gaps between gears are less of an issue. Therefore it is more important to consider the total range, and simply to ensure that i) a sufficiently low gear will be available for the steepest hill and ii) a sufficiently high gear will be available for the highest speed required. In both cases, optimum motor performance is likely to then be achieved with the rider pedaling at a comfortable rate.

Empowering E-Bikes can advise regarding likely hill climbing capability of a given gear setup, and if required regarding potential upgrades to enhance this.

Riding the BBS01

Riding the BBS01