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Electric Bike Buying Advice - All Articles

What are the stand out features of the best electric bike systems for 2017?

We will continue to update this information as details become available.

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Progress in Lithium Battery Technology As the electric vehicle (EV) and ebike market continues its rapid growth in both the US and the UK, some exciting news has recently been announced which will have a major effect on the industry. Researchers have developed a new battery system which will allow EVs to be recharged almost instantaneously.  This technology, dubbed the ‘Ifbattery’ by its creators, can be produced cheaply and is environmentally friendly. It uses a system known as a flow battery, but has been adapted to work without the membranes usually used in such units. T..

Brompton Electric Launches Pre-Order

Brompton Electric Launches Pre-Order

Brompton Electric Taking Pre-Orders

After years of research and development Brompton are starting to take orders for their electric bike and I'm sure they'll be inundated with orders.

The 2 speed will weigh 16.6Kg and the 6 speed will weigh 17.3Kg including the detachable 300Wh lithium battery bag which weighs 2.9Kg.

Prices will range from £2595 to £2755

To work out what the motor and other eGroupset components weigh I've specified a bike as closely as possible to the electric spec and you can see from the following:

Your chosen primary components

  • Frame Material: SteelWeight: 0.00 , Price: £ 0.00
  • Handlebar: M TypeWeight: 10.34 , Price: £ 825.00
  • Gears: 6 SpeedWeight: 0.92 , Price: £ 170.00
  • Mudguards/Rack : Version L - inc. mudguards but no rackWeight: 0.37 , Price: £ 55.00
  • Main Frame Colour: BlackWeight: 0.00 , Price: £ 0.00
  • Extremities Colour: BlackWeight: 0.00 , Price: £ 0.00

Your chosen secondary components

  • Gear Ratio: 6 speed std ratioWeight: 0.00 , Price: £ 0.00
  • Saddle Height: StandardWeight: 0.00 , Price: £ 0.00
  • Lighting: Shimano Hub DynamoWeight: 0.44 , Price: £ 100.00
  • Saddle: BromptonWeight: 0.00 , Price: £ 0.00
  • Suspension: StandardWeight: 0.00 , Price: £ 0.00
  • Tyre: Brompton KevlarWeight: 0.00 , Price: £ 0.00

Your chosen Luggage

  • Front Luggage: Front Carrier Block OnlyWeight: 0.09 , Price: £ 15.00
  • Rear Luggage: NoneWeight: 0.00 , Price: £ 0.00
  • Transporting, BBag: NoneWeight: 0.00 , Price: £ 0.00
  • Saddle bag: NoneWeight: 0.00 , Price: £ 0.00
  • Toolkit: NoneWeight: 0.00 , Price: £ 0.00

 Total weight: 12.2Kg RRP listed £1165.00

This would suggest that the non removable eGroupset components weigh 2.2Kg (17.3-12.2-2.9Kg(battery bag)) which is impressive considering it allows for a 'contactless' torque and cadence sensor, cables, connectors/contacts, possibly switches and display and possibly beefed up spokes, washers, brackets and luggage mounts.

Although not perfectly clear yet if the 6 speed costs £2755 the premium charged for the entire eGroupset will be £1590.

As we'd expect the eGroupset and bike have been certified to the exacting electric bike standard EN15194 and the battery to UN38.3 and EN62133. Many electric bikes sold online and even in some shops do not meet these standards and purchasers have no guarantee that they are safe to use.

OK so you have the overview now lets dig a bit deeper.

The Motor

The Brompton Electric motor is described as a brushless DC motor with a nominal power output of 250W a very low resistance for cycling unassisted and an extremely high power to weight ratio. It's interesting that they do not suggest that it's a direct drive motor. Brushless motors can be geared or direct drive please see our buying guide here for more on these types of motors. If Brompton have managed to squeeze a geared motor into the standard Brompton fork over lock distance of approx 74mm without sacrificing performance they have achieved something. This would explain a low free rolling resistance from the motor wheel and the potential for a high power to weight ratio. If they have used a direct drive motor the width of the motor would be easier to achieve however it would be likely that there will be some noticeable free rolling resistance and a relatively low performance. A benefit of a direct drive motor would be the ability to recharge the battery when braking or descending and although this is complicated to achieve reliably, especially with lithium packs Brompton would have been very tempted to include this feature if the motor could facilitate it. Therefore my conclusion is that they are using a brushless geared DC motor.

The Battery


300Wh lithium batteries are pretty much the starting point for premium electric bikes and I'm sure Brompton will offer some upgrade options with a longer range if the demand exists. For an efficient motor a range of 25-50 miles seems reasonable. We don't know what cells Brompton are using or what battery data will be displayed in the app. We can see an LED battery gauge on the top of the battery bag to give riders an indication of remaining range. Will Brompton have a remaining range estimate on the app? Do they show a % state of charge or a simple voltage reading? We'll have to wait and see.

Battery Mounting - The battery bag will mount onto what I imagine is a special mounting block with some contacts to allow transfer of controller signals and power. It isn't specifically stated but based on the 2.9Kg battery weight and onboard functions I think it's likely that the control electronics are located in the special battery bag and not hidden somewhere in the frame.


Rider Experience

With a good torque and cadence sensor the bike should feel quite natural to ride with an amplifying effect applied to the rider effort allowing them to ride as normal but feel stronger accelerating easier and faster than usual. A huge part of the Brompton Electric rider experience will depend on the algorithms (applied to the sensor data feed) that decide how to integrate the motor power with what the rider and bike are doing. Many electric bikes use the same sensors but only a few manage to interpret the data to provide the perfect electric bike response to keep the rider and components comfortable and happy. Finding the right balance between liveliness (torque response), range, feeling of control and reliability is crucial. After 6 years of making ebike systems and with the data feed from millions of ebikes Bosch are still tweaking their software to provide the right response for the many different riding requirements and styles that are out there.

Assist Levels - there are 4 ranging from 0-3 which keeps things simple in typical Brompton style. It would be good to know the % of assist applied at each level.
The interface appears to be currently restricted to an iPhone app and it is as of today not live on the Apple App Store. May be most Brompton owners prefer Apple products but I would guess that Brompton will have an Android app soon. Will the phone app interface be a success? I guess that depends on how crucial it is and how often a rider would need to defer to it for some commonly changed setting or often checked information. Our experience is that most Brompton riders want to keep things practical and simple.

Bike

 Information

Wheel size

16" (349mm)

Folded dimensions

585mm high x 565mm long x 270mm wide (23" x 22.2" x 10.6").

Handlebar type

M type (1015mm)

Rear frame

L type (mudguard)

Colours

Gloss black or Gloss white

Gears

2-speed or 6-speed

Seat posts

Standard - adequate for an inside leg measurement up to 33"

Extended - 60mm / 2.5" longer than the standard option

Telescopic - designed for an inside leg greater than 35"

Weight: bike without battery

2-speed: 13.7kg (16.6kg total with battery)

6-speed: 14.4kg (17.3kg total with battery)

Weight: battery & small bag

2.9kg

Lights

20 Lux Busch & Müller LYT

Max. load

107kg (incl. luggage)

Brakes

Dual pivot brakes

 

 

Luggage

 

Small bag (included)

1.5 litres 

Large bag (optional accessory)

20 litres - additional £130

 

 

Charger

 

Standard charger (included)

2A charger (80% charge in 3-3.5 hours, 100% in 4-5 hours)

Fast charger (optional accessory)

4A charger (80% charge in 1.5-2 hours, 100% in 2.5-3 hours) - additional £115

 

 

Battery

 

Voltage

36V

Capacity

8.55Ah

Energy density

300Wh

Range

25-50 miles / 40-80km (dependent on rider and environmental factors)

USB port to charge portable devices

5V 1.5A

Integrated HMI

LED display

Weight

2.2kg

 

 

Assistance

 

Assistance modes

4 (0-1-2-3)

Sensors

Contactless bottom bracket torque and cadence sensor

 

 

Motor

 

Type

Brushless DC front motor

Nominal output power

250W

Cut off speed

15.5mph / 25kmh

Freewheel

Very low resistance when riding without assistance

 

 

Warranty on electrical parts

2 years

 

 

Certifications

EN15194
Battery: UN38.3, EN62133

 

 

App

iPhone app 

Who is confident Brompton will have nailed it? Well being huge Brompton fans we are confident the electric Brompton will be everything they've promised.

Brompton are currently asking for a £200 deposit to reserve one of the 1st Brompton Electric bikes.

The complete specification is below:

Full Specification 

 Our Sparticle kit for Brompton has been making electric bromptons electric for almost 12 years. Of course it's evolved over this period into a magnificent performer. It's very different to the Brompton Electric but certainly worth a test ride. See the details here.

Whatever you do - get an electric Brompton - you'll love it!

Posted by Eddie Kehoe