LocationCambridge, England United Kingdom map
Web/EmailWebPage email image
Vehicle2008 Sakura S50
Moped based on Baotian Scout type body. Marketed in the UK as Sakura S50. Manufactured by Erato in China, who became E-fun, and this scooter is essentially the E-fun A, which is still in production.
MotorErato Brushless DC
1.5kW nominal hub motor, with switchable windings for 2 'gears'.
Drivetrain1.5kW brushless DC hub motor with delta/wye switching.
50A non-regenerative BLDC controller. PCB Marked 'BLC3000'
Batteries48, 3.20 Volt,
16S3P pack of Headway 38120S 10Ah LiFePO4 cells. built as 4 4S3P packs.

Replaces original K-Long (taiwanese 36Ah SLA)
System Voltage48 Volts
Charger Meanwell 350-48 PSU, modified
Standard Meanwell 350W 48V PSU set to 57.6V and modified to give a 6A current limit. Very cheap at £50 delivered.
DC/DC Converter
Erato-supplied stock converter
InstrumentationAnalog Voltmeter (very useful and accurate state-of-charge indicator once you get used to the on-load/off-load characteristics), Speedometer, Odometer.
Watts-up used for charging monitoring and cycle analyst used during travel.
Top Speed31 MPH (49 KPH)
Standard UK Moped top speed. Maintained on cambridgeshire hills and bridges.
AccelerationGood, except for first couple of seconds away from lights where other vehicles can be faster. Using '1st gear' solves this problem, but gear change is slow, and not entirely reliable, so generally leave it in 'top'.
Range20 Miles (32 Kilometers)
Max range not yet tested. 19km/12.5 miles leaves battery still at very similar voltage to when setting off - can clearly go a lot further.

With original SLA batteries my 12.5mile commute could use up all the juice at full speed/acceleration on a cold day. Can go twice as far if you do 15mph instead. I charge at work and use daily. SLA battery life declined to about 12 miles max after 2000 miles (15 months) use.
Watt Hours/Mile56 Wh/Mile
From many trips to work. 12 mile commute, 1/3rd stop-start through town, 2/3rds open road, mostly full-speed.
EV Miles
Start:23 Miles (37 Kilometers)
Current:2,400 Miles (3,861 Kilometers)
Total:2,377 Miles (3,824 Kilometers)
    As of 2/23/2010
Seating Capacity1 (2 small adults at a pinch)
Curb Weight100 Pounds (45 Kilograms)
Conversion Cost£850+£55 for registration.
£670 for lithium battery upgrade
£150 for instrumentation
Additional FeaturesBack box.
Very good value commuting machine. Adequate performance and handling. Cheap to run. Various minor build-quality/assemly issues had to be dealt with initially. Very reliable. Tendency of motor shift mechanism to move into 'neutral' on heavy/emergency braking is tiresome, especially the first time. Headlight uninspiring.

Upgrade to 30Ah48V Lithium makes it noticeably more nippy and responsive due to weight reduction and reduced voltage sag under load. Range nearly doubled. Flat discharge curve means performance does not degrade during discharge as it steadily did with SLA.

code by jerry