induna
100 mW
I've been reading and thinking for quite a while about building a new e-bike. This will be my second, but the first was a simple, 36v 250W front hub motor with a Ping battery that I used for my short commute to the Rapid bus stop in Phoenix. Now, however, I live in the mountains of far southern Costa Rica (about 5 km from Panamá as the Oro Péndula flies), and the challenges are quite different. I live pretty much on the high spot of the main road at 1300 meters of altitude. The 4 km trip to town drops about 300 meters, most of that on an uninterrupted 2 km long slope, and that is far from the most challenging slope around. For example, the 'big' town about 30 kms away is at sea-level, and the vast majority of the descent occurs over about 12 kms. In addition to the asphalt roads, which are actually in very good condition, although rather narrow, there are a lot roads paved with loose stone, many of which are very steep, that I also want to travel -- slowly. In addition to the terrain, the weather is a factor. We average 4 meters of rain a year here, so it is inevitable that I will get caught in extreme downpours, even though I won't be trying to.
Rider needs/vital statistics:
I'm 182 cm tall and weigh 85 kilos and I would also like to be able to carry groceries, etc. from town to my house.
Top speed needs to be 35 kph at most, range and the ability to climb steep slopes with bad traction slowly without overheating the motor is more important. (I live in a beautiful part of the world and I'm pretty much never in a hurry to get anywhere.)
The bike needs to be able to tolerate rain and function well in a wet environment.
I would also like the bike to be easy to operate. I personally don't care if it is complicated and finicky, but I would like to lend it to others to ride as well. I really like e-bikes and I would like to be able to introduce them to my friends who live around here, most of whom would never consider riding a bike to town and back because of the difficulty presented by the hills.
I would like to keep the price under $1500, excluding the bike. I plan on trying to scrounge up a good used one, which could take some time out here in the boonies.
So, given the above, here is how I think I want to accomplish my goals:
A 26" mountain bike, probably hard tail, that can take disc brakes (which I believe to be essential given the long, steep descents and rain).
A Bafang BBS02 or BBSHD mid-drive kit from Paul or Lunacycles depending on how how shipping and duties work out. I would prefer the smaller motor, but the BBSHD might end up being the better choice. From what I've read, a mid-drive is probably the only way to go given the terrain.
A 48v or 52v 18650 pack with as many amp hours as I can afford given my budget, a minimum of 12. If I buy from Paul, I'll go 48v, and if I buy from Luna 52v. Obviously if I buy the BBSHD, 30 amps sustained will be required from the pack.
To address the possible chain line issues, help the ride-ability of the mid-motor, and provide the necessary gearing I want to use an Alfine 8 speed IGH on the rear. To further help with ride-ability I want to use the gear sensor cutout switch and dedicated port available through Lunacycles, or fabricate a throttle-based power cutoff triggered by the shifter as outlined by Kepler. I plan to run the bike primarily using the pedelec modes, and would love for anyone to be able to ride it easily with very minimal training -- basically just pedal and shift gears as on a normal bike
I would really appreciate any comments and criticsm of this plan, and any practical advise of sourcing parts, good bike shops, dealing with customs (especially for the batteries) from others who live in this part of the world will be gladly re-payed with a cold Imperial.
Just to give you a better idea of the type or terrain I'm talking about, here is a picture from my front porch (I am very lucky):
Rider needs/vital statistics:
I'm 182 cm tall and weigh 85 kilos and I would also like to be able to carry groceries, etc. from town to my house.
Top speed needs to be 35 kph at most, range and the ability to climb steep slopes with bad traction slowly without overheating the motor is more important. (I live in a beautiful part of the world and I'm pretty much never in a hurry to get anywhere.)
The bike needs to be able to tolerate rain and function well in a wet environment.
I would also like the bike to be easy to operate. I personally don't care if it is complicated and finicky, but I would like to lend it to others to ride as well. I really like e-bikes and I would like to be able to introduce them to my friends who live around here, most of whom would never consider riding a bike to town and back because of the difficulty presented by the hills.
I would like to keep the price under $1500, excluding the bike. I plan on trying to scrounge up a good used one, which could take some time out here in the boonies.
So, given the above, here is how I think I want to accomplish my goals:
A 26" mountain bike, probably hard tail, that can take disc brakes (which I believe to be essential given the long, steep descents and rain).
A Bafang BBS02 or BBSHD mid-drive kit from Paul or Lunacycles depending on how how shipping and duties work out. I would prefer the smaller motor, but the BBSHD might end up being the better choice. From what I've read, a mid-drive is probably the only way to go given the terrain.
A 48v or 52v 18650 pack with as many amp hours as I can afford given my budget, a minimum of 12. If I buy from Paul, I'll go 48v, and if I buy from Luna 52v. Obviously if I buy the BBSHD, 30 amps sustained will be required from the pack.
To address the possible chain line issues, help the ride-ability of the mid-motor, and provide the necessary gearing I want to use an Alfine 8 speed IGH on the rear. To further help with ride-ability I want to use the gear sensor cutout switch and dedicated port available through Lunacycles, or fabricate a throttle-based power cutoff triggered by the shifter as outlined by Kepler. I plan to run the bike primarily using the pedelec modes, and would love for anyone to be able to ride it easily with very minimal training -- basically just pedal and shift gears as on a normal bike
I would really appreciate any comments and criticsm of this plan, and any practical advise of sourcing parts, good bike shops, dealing with customs (especially for the batteries) from others who live in this part of the world will be gladly re-payed with a cold Imperial.
Just to give you a better idea of the type or terrain I'm talking about, here is a picture from my front porch (I am very lucky):