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Electric Bicycle Technology

Geared Motor and Direct Drive compared

EBS Power Management: Functionality and advantages

Bottom Bracket: Support for determining the bottom bracket type and bb-set diagram

Battery Technologies: Cell types used by Ebike Solutions


Geared motor and direct drive compared



Geared motor Direct drive
Mostly have a freewheel
» bike moves easier without support
» example: Bafang, Mini-folding bike motor, PUMA, BMC
usually do not have a freewheel
small braking torque even when system is switched off
» example: BionX, Crystalyte
Assembled from many components Assembled from less components
» more robust
usually constructed as planetary gear Externally rotating motor
» Housing rotates without interconnected transmission
No recuperation possible
(when motor does have a freewheel)
Recuperation possible
(when motor does not have a freewheel)
» energy recovery possible

Geared Motor

 open gear motor Design:
In contrast to direct drive this motor does not rotate completely within the wheel but only its housing. Inside the motor possesses gears usually a planetary gear that is driven by the motor inside the housing. I doing so the motor on the inside rotates faster than the housing. The gears adapt the motor's high rotational speed to the low rotational speed of the wheel. Because of that torque can reach high numbers even with small housings. At the same torque a geared motor is always smaller than a direct drive.

Hall sensors:
Some geared motors need hall sensors for activation to recognize the motors position and put it into motion. These sensors offer the advantage of a higher starting torque because the motor can start running with high power from the very beginning.

Differences from direct drive:
Almost all geared motors use a freewheel due to which they do not feature a braking effect when riding without electric support. However they loose recuperation capability. Due to its complicated construction a geared motor uses more components than a direct drive making it more prone to failure. Depending on manufacturing quality a running geared motor can be louder than a direct drive.





Direct Drive

 open direct drive Design:
A direct drive mostly is constructed as an externally rotating motor. Magnets are attached to the inside of the housing. While the bike is in motion the housing will rotate completely since it's part of the wheel. To achieve higher torque the housing needs to be built lager, accordingly. So there's no wonder why direct drives are generally somewhat heavier than the small and light geared motors. There are manufacturers like BionX who try to compromise between power, site and weight to produce big but light motors. You need to take into account that improving one factor will result in the restricting of another.

Hall sensors:
non-geared motors usually can be used with or without hall sensors. Without hall sensor the risk of failure is reduced because of the lower number of parts. Hall sensor increase the starting torque since the controller always has exact data about the position of motor and magnets.

Differences from the geared motor:
The fact that a direct drive constantly rotates when in motion offers advantages and disadvantages. There is a slight braking effect when electric support is switched off while riding. How strong this braking effect is, depends on the model of the motor but it is always present. a direct drive's biggest advantage is recuperation. When braking or going downhill energy can be re-stored into the battery, if controller and battery have been prepared to do so. This way the direct drive preserves energy while riding and is easy on the mechanical brake.

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EBS Power Management



The EBS power management allows you to adapt your electric bike's handling very well to your wishes. With the help of this technology you can handle the level of motor support yourself. This enable a precise and personal power management. This way you can control directly if you want to have a smooth or rather fast start.

How it works:
Instead of always going full power you can use the EBS power management to control power supply: The higher the level the more support you get from the motor. This way the transition between steps will be smoother and resulting in a more natural handling. EBS power management also has influence on the pedelec's range. Since the motor uses less energy when running in the lower levels, battery capacity is preserved and the battery will last longer.



The EBS Power Management's advantages at a glance:

Systems without EBS power management Systems with EBS power management
Motor always applies full power Motor power is modulated
Each levels has its own maximum speed: Level 1 to 5 are limited by speed. Each levels has its own maximum speed: Level 1 to 5 are limited by current (A).
immediate release of full motor power up to the respective level's speed limit. Constant increase of motor power up to the level's power limit
In every level, the motor always works with maximum current (e.g.: Pedelec 15A) Motor increases its power with every level: Level 1 = 3A, 2 = 6A, 3 = 9A, 4 = 12A, 5 = 15A
No control over motor power (= same current in every level) Motor power controlled via selection of level ( = selection of current)
Same starting speed (= start with 15A) Dial-in starting speed by selecting level (= start from level 1 at 3A, level 2 at 6A ...)
» sudden start » choice between smooth or fast start
» noticeable, distinct transition between levels » smooth transition between levels
» natural handling
» better ride control
» stated numbers refer to pedelecs

Level chart of EBS 250W Conversion Kits

the single steps are limited by current as follows:

EBS 250W Conversion Kits Power levels 1 to 5
EBS Plug & Drive - 250W Pedelec Conversion Kit Level 1 = 3A, Level 2 = Level 6A, 3 = Level 9A, Level 4 = 12A, Level 5 = 15A
EBS 250W Conversion Kits Level 1 = 3A, Level 2 = Level 6A, 3 = Level 9A, Level 4 = 12A, Level 5 = 15A
EBS 250W Conversion Kits Level 1 = 2A, Level 2 = Level 4A, 3 = Level 6A, Level 4 = 8A, Level 5 = 10A


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Bottom Bracket



Most bicycle bottom brackets can be categorized to three types: square taper, Hollowtech II and Octalink. He have developed a fitting solution for every type for you to be able to convert your bike fast and without any problems. Follow these two easy steps to find the right components for your conversion.



Step 1: Determine bottom bracket

Using the following chart and pictures you can determine, which bottom bracket is installed to your bike. You will need this informations to choose the correct cadence sensor (PAS)

bottom bracket type square taper Hollowtech II Octalink.
square taper bottom bracket Hollowtech II bottom bracket Octalink bottom bracket
Recognition feature Viewed from above the axle is easy to detect the bottom bracket axle has exactly four flattened faces.


Viewed from above the axle is invisible. The cranks directly touches the bearings and are fastened from the outside by two large crank bolts.

Viewed from above the axle is easy to detect.
The axle is round.


Move mouse over picture to enlarge.


Step 2:

Now you know which bottom bracket is installed in your bike and you can read the respective section.



Square Taper

With a square taper bb you can choose one of the following solutions:

Square butt cadence sensor and magnet disc for our IPS and IES
cadence sensor set for tool-free installation
applicable when distance between crank and axle is less than 8mm.
for professional installation
basically suited for square taper bottom brackets





Installation
square taper bottom bracket: splittable magnet disc
No need to disassemble the bottom bracket thanks to splittable magnet disc and adhesive cadence sensor
square taper bottom bracket
Axle mounted PAS disc and bracket-mount cadence sensor





PAS in set
Square taper bottom bracket with splittable PAS disc

aepas4ktb-01
Square taper bottom bracket with PAS disc

aepas4kgz-01
included parts
  • EBS IPS/IES adhesive cadence sensor left
  • EBS IPS/IES adhesive cadence sensor right
  • splittable PAS disc with 12 magnets for square taper axles
  • EBS IPS/IES bracket-mount cadence sensor left
  • EBS IPS/IES bracket-mount cadence sensor right
  • PAS disc with 12 magnets for square taper axles

square taper bottom bracket
cadence sensor set for tool-free installation for professional installation




Tools in set





No assembly tools necessary
square taper set

Attaching the cadence sensor to the bike


Hollowtech II

With Hollowtech II first, check how many chain rings your cranks have. With three chain rings the choice of cadence sensor set depends on the number of teeth of the smallest chain ring. With single or double chain rings the PAS disc has to be attached directly to the crank. The bracket mounted cadence sensor has to be clamped under the right bottom bracket shell.

Hollowtech II cadence sensor and magnet disc for our IPS and IES
cadence sensor set for triple cranks with 22T smallest chain ring for triple cranks with 24 or 26T smallest chain ring for single or double cranks





Installation
Hollowtech II bottom bracket: for 22T

PAS disc with chain ring tab and bracket-mounted cadence sensor
Hollowtech II bottom bracket: for 24 or 26T

PAS disc with magnetic chain ring mount and bracket-mounted cadence sensor





Adhesive PAS disc and bracket-mounted cadence sensor





PAS in set
Hollowtech II bottom bracket with snap-on PAS disc

aepashtII22-01
Hollowtech II bottom bracket with magnetic PAS disc

aepashtII26-01
Hollowtech II bottom bracket with magnetic PAS disc

aepashtII26-01
included parts
  • EBS IPS/IES bracket-mount cadence sensor right
  • PAS disc with 12 magnets for 22T chain ring
  • EBS IPS/IES bracket-mount cadence sensor right
  • PAS disc with 12 magnets for 24 or 26T chain ring
  • EBS IPS/IES bracket-mount cadence sensor right
  • PAS disc with 12 magnets for 24 or 26T chain ring

Hollowtech II - assembly tool for all Hollowtech II bottom brackets.




Tool set
Hollowtech II set

Hollowtech II assembly tool set


Octalink

With Octalink bottom brackets first, check how many chain rings your cranks have. With three chain rings the choice of cadence sensor set depends on the number of teeth of the smallest chain ring. With single or double chain rings the PAS disc has to be attached directly to the crank. The cadence sensor with adjustable bracket is attached to the seat tube using zip-ties.

Square butt cadence sensor and magnet disc for our IPS and IES
cadence sensor set for triple cranks with 22T smallest chain ring for triple cranks with 24 or 26T smallest chain ring for single or double cranks





Installation
Octalink bottom bracket: for 22T

PAS disc with chain ring tab and bracket-mounted cadence sensor with adjustable bracket
Octalink bottom bracket: for 24 or 26T

PAS disc with magnetic chain ring mount and cadence sensor with adjustable bracket





Adhesive PAS disc and cadence sensor with adjustable bracket





PAS set
Octalink bottom bracket with snap-on PAS disc

aepasocl22-01
Octalink bottom bracket with magnetic PAS disc

aepasocl26-01
Octalink bottom bracket with magnetic PAS disc

aepasocl26-01
included parts
  • EBS IPS/IES cadence sensor with adjustable bracket right
  • PAS disc with 12 magnets for 22T chain ring
  • EBS IPS/IES cadence sensor with adjustable bracket right
  • PAS disc with 12 magnets for 24 or 26T chain ring
  • EBS IPS/IES cadence sensor with adjustable bracket right
  • PAS disc with 12 magnets for 24 or 26T chain ring

Octalink - assembly tool for all Octalink bottom bracket




Tool set
Octalink Set

Octalink assembly tool set

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Battery Technologies



Why does Ebike Solution sell Lithium-Ion batteries exclusively? Lithium-Ion technology is superior to any other technology in practically any aspect. Because we only want to offer you the best, we rigorously refuse to sell any other battery technology. Here you can see different battery technologies in comparison:

Battery technology Lithium-Ion (LiIon) Nickel-Metal hydrid (NiMH) Nickel-Cadmium (NiCd) Lead (pb)
Energy density + o - -
Longevity + o - -
Voltage + o o -

Battery chemistry

Different types of lithium-Ion-batteries can be distinguished by their different battery chemistries. Ebike Solutions uses cells with lithium-manganese-oxide (LiMnO), lithium-nickel-manganese-cobalt (LiNiMnCo) and lithium-nickel-cobalt-aluminium (LiNiCoAlO)

Cell types used by Ebike Solutions

What matters most to make a long-lasting, safe and powerful battery is not only battery technology and chemistry but especially good manufacturing. Many suppliers of cheap cells advertise longevity with charging cycles in the four-digit region. In fact these cells mostly are badly manufactured and never actually reach the claimed number of cycles. Ebike Solutions solely relies on meticulously tested cells from selected manufacturers. The manufacturers of the cells used by us belong to the best in the world. Due to their experience and high manufacturing standards they are constantly able to offer battery cell in excellent quality.

To build our batteries we use type NCRP type cells as a standard, because these offer an excellent combination of energy density and voltage level. These cell are designed as cylindrical cells and they're equipped with a pressure relief valve. Therefore when overcharged they don't catch fire and they do not explode. These cells use the format 18650, meaning they measure 18mm in diameter and 65mm in length. Each cell weighs approx. 45g.

NCRP cell are only surpassed by cell of the new NCBD type that offer an increased capacity of yet another 10%. If you are interested in these cell, call us.


Cell type EBS18650NCBD EBS18650NCRP
Energy density +++++ ++++
Longevity +++ +++
Voltage level +++ +++
Rated capacity 3.2 2.9
gravimetric energy density
single cell (Wh/kg)
255 230
gravimetric energy density
in pack* (Wh/kg) approx.
210 190
volumetric energy density
in pack* (Wh/l) approx.
385-440 350-400

*depends on discharge rate

EBS18650NCRP
This hi-tech cell provides an outstanding energy density and is high rate discharge capable, Ebike Solutions uses the EBS18650NCRP by standard for all of our self-assembled batteries. This cell type is ideal for light and powerful e-bike batteries thanks to its very good voltage level, cell capacity and fast-charging capability. Battery packs made from these cells contain a protective circuit board (BMS), that, if necessary adapts different cell voltages to the same level and switches off the battery in case of overcurrent, overvoltage or after total discharge.

Custom designing our EBS battery packs

We build batteries from solid cylindrical cells. We usually do not use foil-wrapped polymer cells, since these are mechanically unstable and can bulge by ageing. The EBS18650NCRP cells use Lithium-Nickel-Cobalt-Aluminium (LiNiCoAlO) as their battery chemistry.

Arranging cells in a square pattern makes the most sense in battery construction. Cells can also be arranged hexagonally in a honey comb shaped pattern, but that makes manufacturing more complex and therefore more expensive. Of course we can fulfil any other demands, like using a certain cell type, a separate charging port, a balancer exit according to Schulze-standard and much more.

Send us an email about your ideas or call us.

Contact us

Why does Ebike Solutions normally NOT use LiFePO4 cells?

We only use LiFePO4 cells, also known as lithium-iron-phosphate cells as very rare exceptions. Batteries using LiFePO4 technology offer several disadvantages. First, with the same energy they are up to twice as heavy and twice as big as a LiNiCoAl-Oxide battery. Second, a LiFePO4 battery with the same energy is about 50% more expensive. There's cheap iron-phosphate batteries in the market, yet these do never reach the claimed amount of charging cycles, since their cells do not offer the required quality. Therefore we only recommend hi-quality batteries, yet these, of course, have their price.

LiFePO4 based batteries only make sense when significantly more than 1000 charge/discharge cycles are needed. Our standard batteries already provide you with range of up 40,000km (25,000mls) at around 700 cycles. Mostly batteries will be rendered useless by unavoidable ageing not by too many charging cycles.

Iron-phosphate batteries age about half as fast as LiNiCoAl-Oxide batteries. Yet buying an expensive iron-phosphate battery mostly doesn't pay, since battery technology advances very fast. Every year batteries become about 5-7% lighter and smaller at the same capacity. Therefore Iron-phosphate batteries become obsolete during their lifespan. It makes more sense to invest in a smaller and lighter LiNiCoAl-oxide battery. When after a couple of years the battery is used-up you can profit from the progress made in the meantime by buying a new battery that now provides up to 40% more capacity.

What is a Battery Management System (BMS)?

BMS is an electronic circuit for battery monitoring. It increases a battery pack's safety by making sure that all cells are operated within the permitted voltage range only. When current is too high, temperature is too high or one line of batteries inside the battery is outside the permitted voltage range the charge output will be switched off. This avoids total discharge of the battery during normal operation. Caused by unavoidable self discharge, an insufficiently charged battery can drop to a too-low voltage level. These can be avoided by recharging the battery. Find further information about total discharge here.

An integrated balancer insures that any differences in voltage between single cells are equalized. The occurrence of these voltage differences is called "drift" and results in the fact that the affected battery cannot supply its full capacity anymore. This problem can be avoided by balancing the battery. In most cases batteries will only be balanced until the end of the charging process, depending on the BMS's architecture. Therefore it is recommended to occasionally charge the battery to full capacity.

In case of a problem with the charging device the BMS makes sure that the battery cannot be overcharged. A capacity gauge maybe included to display the remaining capacity.

Custom-tailored battery packs

You need a special battery? We build batteries to your requirements, supply lithium cells for do-it-yourself configuration and we also repair your old battery. This is what's possible:

  • Several rated voltages (24/36/48V and more)
  • different shapes, e.g. to fit into a housing or bag
  • Fitting new cells into old battery housings, if possible.
  • Lithium cells and accessories with desired electrical features

Tell us your wishes and we will make you an individual offer.

You don't need to be an expert: Tell us your requirements and we will find the best solution.

Call us!


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