Electrified a Tern Eclipse 24" folder

TimJohn

Active Member
Hello All,

Finally found another Tern folding bike to convert. I picked up a used Tern Eclipse that has the features I like in a bike. My previous project was a Tern Verge Si8 and its been trouble free and offers numerous features that lend itself to be an excellent conversion.

The Tern line Eclipse was one of the models that had a major recall because of faulty welds on the frame. The seller had the warranty work done (completely new frame). This model has hydraulic brakes, enclosed Shimano Alfine HUB 11 speed and 24" wheels. But the drive train is still a chain but sort of enclosed or wrapped by a plastic casing.

I installed a Bafang M311 250 Watt motor with a 36 volt 16.5 Ah battery, controller from GRIN, computer from GRIN (Cycle Analyst V3), a throttle, a crank peddle assistant sensor, on/off switch and enclose the battery in the rear bag.

IMG_2385.jpg

Now I have two e-bikes and can get my better half to ride along. We even purchased a "buddy-rider" for our dog!
 

TimJohn

Active Member
Got the baserunner_Z9. It fits very nicely into the packaging of the battery. Phaserunner is a separate package that would have to find a place to mount on the frame.
 

TimJohn

Active Member
OK now that I have had this for a couple of weeks here is my assessment. This is a much better riding e-bike than my 20" Tern Verge Si8. I guess its the 24" wheels that make the ride smoother and more stable. All things equal here because I used the same motor, battery voltage (36 v) and controller but it does achieve a higher speed. It just feels nicer to ride. The only draw back is it has a chain drive So I found out about a VEER belt drive system that can be used with my Alfine 11 speed hub and crank set but the price is a bit high ($395 plus a riveting tool $29). So I am so glad to have done this.
 

Timpo

Well-Known Member
Got the baserunner_Z9. It fits very nicely into the packaging of the battery. Phaserunner is a separate package that would have to find a place to mount on the frame.
I see

The Phaserunner might have been a bit overkill anyways.
 

TimJohn

Active Member
It was also about $100 more expensive. Maybe you can let me know that advantages of the controller. The baserunner_Z9 was compact and could be programmed even for higher amp/volt batteries.
 

TimJohn

Active Member
Well so much for the reliability of the Bafang M311. Only 70 kms on this motor and its making a real racket so I think something has broke loose inside the motor. I don't think I over stressed it. It just started to get suddenly noisey during a short climb up a hill. I applied a short burst of throttle and then it broke. I felt the outside housing and it didn't seem to be hot or unusually warm. I have another bike with the identical setup and even from the beginning I did notice this motor was not as quiet. Little grumblings going on but I didn't think much of it.

I am so tempted to open it up but I will wait until I hear a response from GRIN. See if its covered under warranty.
 

TimJohn

Active Member
OK kinda late to follow up here but the motor is fine. After disassembly, everything inside the Bafang 311 motor checked out. I think it was loose in the front fork and slightly twisted so stressed the inside bearings. Once I torqued down the front end bolts and seated the front wheel, the squealing disappeared. Otherwise for the last 3 months, reliability as expected has been good. I installed a headlamp and modern tail lamp and we are good to go. The range is around 50-60 kms.