Reset – Electric RG 2.0

A quick summary of the project so far

Back in 2010 I acquired a 1985 Suzuki RG250 for the conversion. I spent the next 3 years selecting and buying parts, rebuilding the rolling chassis and assembling all the parts into a working and registered bike.

Bike Park

Things I have learnt

The hardest part of the bike conversion is building, configuring and managing the battery setup. Limited space on the bike and the “shape” of that space makes constructing and mounting the battery pack very difficult. With this in mind I used Headway cylindrical cells allowing me to create quite an organic shape. However the construction method has meant I have never been able to get the pack running perfectly. The motor and controller is not difficult to mount, configure or use, even when using a prototype motor.

Things that have changed

Battery technology has marched forward at a great rate. Chemistries and brands that were impossible for individuals to acquire are now available via either spare parts for electric bikes and cars or via near new condition as large companies have left over batteries from research and development projects. One large example of this is the liquidation of stock from the BetterPlace company.

The little components to build an electric vehicle project have cheaper, more available and a larger range of options. New lighter contactors, fuses, DC/DC convertors and battery management systems.

Changes included in the rebuilding

New batteries

I have been lucky enough to get onto a purchase of some extremely good prismatic batteries. These Kokam batteries are like large foil pouches which have the layers of cathodes, anodes and electrolyte sealed inside. They are large rectangular and quite flat and unlike my current Headway batteries they have no real structural integrity of their own. These batteries also run at a higher nominal voltage (3.7 rather than 3.2) and each cell is 31ah rather than 10ah. This means my new pack will have 40 cells compared to the 120 cells I now have to run. In turn this means a more reliable, easier to manage pack overall. These batteries are also capable of delivering significantly more power than my existing setup.

Specification Current Batteries New Pack
Cell Type Headway 38120s
Headway Cells for Bike
Kokam SLPB 255 HR2
Capacity 10 ah 32 ah
C-Rate Continuous 3C (or 5C depending spec page) 12C
C-Rate Peak 10C 15C
Nominal Voltage 3.2 volts 3.7 volts
Weight 0.33 kg 0.84 kg
Pack layout 24 series of 5 parallel cells 2 parallel sets of 20 series cells
Pack Capacity (Max) 3.8 kwh 4.7 kwh
Pack Weight (Cells only) 39.6 kg 33.6 kg
Pack mounting & connectivity TBA TBA
Pack Continuous power 11.5 kw (or 19.2 kw) 55 kw

New BMS (Battery Management System)

Along with the new batteries I am also updating the way I manage the batteries in the pack. Zeva ( have released a new set of boards and control units for battery management. They are small, light and fully featured making them ideal for use on a motorcycle. Four boards, a central core and a display unit will be able to monitor each cell individually and protect the cells during charging and discharging. Along with the core the setup lets me drive the standard fuel gauge as a state of charge meter, the tacho as an instantaneous amp meter and the temp display will display motor temp (with an additional temp sensor in the motor).

Zeva BMS Display
Zeva Display

Updated 12 volt setup

At a minimum I will be redoing the 12 volt wiring loom to work with the new BMS and the new component layouts. I am also looking at wiring up a RFID or wireless setup for “startup” and charging. To this end I am very tempted to buy the MotoGadget m-Unit device to replace my fusebox, flasher relay and headlight relay. It also has a RFID accessory to support the keyless startup.

MotoGadget m-Unit

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s