A Build for the Tropical Mountains

[induna]

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):

 

[motomech]

Pura Vida,
I lived and worked in CR for 7 years and I may be able to lend some insights.
As far as aduana is concerned, you are right, you don't want to deal with them if you don't have to. They will try and screw you, especially when they see the batteries. And expect high impuestos for that kind of stuff.
When I lived in Nicaragua, I would import directly to the DHL office(I think, maybe Fedex)and they dealt with customs. I think you can do that in CR too. San Jose, of course. At any rate, you will need an agent, or at the least, A Tico that knows the ropes.
Now for the stuff you don't want to hear.
I would just buy a Chinese scooter or small motorcycle because;
-Your ebike will end up costing you more than you think.
-When building your Ebike, you won't be able to run down the the hardware and get the little stuff that seems to always be needed.
-It will be easy to steal
-Ebikes don't like extreamly wet enviourments and are almost impossible to water-proof.
-Although I know the area where you live is rural and the roads are lighty traveled, I have never felt safe riding a bicycle in L. America. No shoulders and way too many drunks on the road.
-China bikes in CR are very reasonable to buy , in fact, it would be about the same or less than in the States. How many things in CR can you say that about? And there are hole-in-wall moto shops everywhere that work for almost nothing. I once had a rear wheel come apart(it was a very rough road) and lo and behold there was a shop. The guy respoked and trued it and the bill was like $13 US. And I don't know if you know this, but when you buy a new bike at the dealer, they registar it and it has insurance for a year. All you have to do is go back and get the tag.
-You can ride both of your girl friends on a MC at the same time(una sandwich ).
I'm sure there are other reasons a motorcycle is better than an Ebike in CR, but I can't think of them now.
I guess I don't get an Imperial for that advice.

 

[induna]

Motomech,

I hear what your saying, but I really don't want to go down the moto/scooter path. I rode a motorcycle everyday, rain or shine, for almost 15 years in both North Carolina and Arizona, but I won't ride here. The moto culture is just way too different for me. Plus my wife would be very unhappy, for a while anyway. I don't need an e-bike. I have a good car and live right on the, as you know amazingly cheap, bus route, but I could use a project and some exercise at the same time.

I'm not too worried about being able to get stuff as I move forward, other than batteries. I can order something from Amazon and have it at my post office in 5 days, and the taxes on bikes and bike parts are pretty cheap. Plus, the local hardware stores are pretty good and Paso Canoas, where you can apparently buy almost anything, is only 45 minutes away. In any case, I really do appreciate the feedback, and I'll update the thread as I move forward, even if it becomes a big fiasco. If you're ever in Coto Brus, an Imperial is waiting.

Pura Vida.

 

[motomech]

Ok, but you might look into importing the battery before you get too far along.
I did a "test" order from Hobbyking and they won't ship to CR.
A couple of years ago I tried to ship batteries into Nic. and couldn't do it.
Maybe john in cr knows how best to do it.
You could PM him.

 

[induna]

Thanks for that. I tried Hobbyking, and it looks like they will ship, but not cheaply. I'm probably going to go with 18650 pack with BMS in any case, and Paul will definitely ship here, and I hope Lunacycles will as well. Nothing will happen soon, and I'll definitely PM John for any advise he might have as a result of his long experience. But first, I need to find a bike!

Ciao.

 

[motomech]

If you had a friend come down on a tourist visa, they wouldn't bother him about a bicycle at the airport customs.

 

[John in CR]

You'll ride a motorized bicycle, but not a moto?? Chinese ebikes could work down on the flats at beach level, but they're a guaranteed fail in the mountains.

You need low gearing, and whether you realize it yet or not, you need regen braking so you don't have to fiddle with mechanical bike brakes nearly as much. Starting at the top of the hill is a special challenge, because you can't fully charge your battery since it needs to accept charge on the way down. That makes a Cycle Analyst a mandatory piece of equipment to determine the proper top-of-charge voltage you need.

It's good that speed isn't important. Then you can take a system good for 60-70kph and gear it down to 20-30 and you'll be able to climb anything without heat concerns. Running a motor through the gears will help make climbing easy, but reliability takes a big dump, maintenance goes way up, and you lose regen braking. Driving the wheel directly gives you regen, but forget about pedaling home. I live outside San Jose, so my worst case is flag a truck down and pay for a ride home for me and the bike, which only happened once, way back in 2009.

For your exact case, I'd go 2wd with direct drive hubbies in small wheels. Get a cable throttle to hall sensor converter from Gwhy, so your electronic throttle isn't exposed to rain. Spring for a marine switch to activate regen, and attach controllers metal on metal inside a waterproof battery bay available on several ebike designed frames. I avoid the rain as much as possible due to the loss of traction.

I've got batteries, minimum 30ah format cells. I've also got some motors and frames I might consider parting with.

Your concern about riding a moto worries me. You need to go into this with the understanding that you will with near certainty hit the ground. Even going quite slow (the only way I've eaten pavement or rocks) rocks, concrete, and asphalt are painful.

John

 

[induna]

John,

I really appreciate your suggestions. I would like the e-bike to be as much like a mechanical bike as possible. I basically want to use it for fun, exercise, and the ability to make some local trips and do some errands without using my gas-guzzling Toyota 4X4. I want to pedal, but I don't want to have to pedal up the hills without some assist because otherwise it will be too painful and I won't do it. I also want the user interface for the bike to be very bike-like, hence primarily pedal assist. I don't want an e-bike that is ridden as a moped. These are the reasons I was leaning pretty heavily towards a mid-drive setup, accepting that they are more mechanically complex, but I do have the time and skills to perform maintenance, and it's not like I can't get around easily if I have to wait for parts to get here by boxcorreos or EMS.

You place a lot of importance on the utility of regen braking for the hills, and I understand that. I had a Honda Insight when they first came out, and the regen brakes were pretty awesome on long descents and definitely helped save the brakes. But if I go with DD hub(s), I pretty much give up the ability to ride it like a bike, don't I? Don't you think a good set of hydraulic disc brakes would also be safe and reliable on the long descents, especially if the bike is kept pretty light?

I will definitely look into the cable throttle to hall sensor converter, and waterproofing all of my exposed switches. One of the reasons I was attracted to the Bafang mid-drives is that they are reported to be quite water-tight electrically, although I guess the older style seals weren't all that effective at keeping water out of the mechanicals, and, even in the best of cases, will probably require a tear-down every 6 months or so here. I've learned that what people in the States consider to be a really wet climate isn't really all that wet :lol: I don't plan to ride in the rain, but I know that I will be caught in it once in a while.

As far as motos go, I really just don't want to ride them anymore. I rode a lot of miles for a long time, and I always dressed to crash and expected that everyone was trying to kill me. That really helped keep me out of trouble. I plan to take the same approach with the bike, but it is different. Yes, the drivers are at least equally as evil, but the bike is much slower and lighter, and the roads I'm traveling are a lot less crowded. In addition, a lot of the other drivers around here basically hate motos, but are generally just benignly neglectful of bikes, or so I hope. I fully expect to crash, especially on the lastre roads, but I'll do my best to avoid it if possible, and if not, to crash slowly. If riding becomes too stressful, then the bike really won't be serving its purpose and I'll move on.

In any case, I've got a lot to think about. Do you mind if I PM you in the future to ask some questions specific to CR, like impuestos, aduanas, local resources, etc. that really won't be of interest to most members?

Thanks again for your ideas, John.

 

[John in CR]

Nothing at all wrong or especially difficult about having a pedal line too and wanting to use it. It's pedal only or pedal as backup that you giving up, and that's not entirely the case, since you could remove the chain or belt from a non-working or out of juice electric system and use the pedal line that works in parallel. That means it wouldn't be a moped in the European sense, useless pedals on an under-powered lightweight motorcycle.

You could go with the Bafang system or for more omphf with a Cyclone system. Then carry an extra chain with you, since you should consider them consumables like brake pads, but a chain can go at any time and needs to be in the toolbag.

Down near the southern frontier I can't imagine any kind of bike being treated better than here, which means ride at the side where debris, rain ruts, glass, metal, etc reside leaving you as a slow moving obstacle that every drunk and texter must avoid. I'd stay in a metal cage instead of that, but plenty of people seem to feel safe that way. For me, cars are the slow moving obstacles I avoid, so no riding at the side for me.

Regardless of speed desired I firmly believe in building ebikes in a manner that you can assume absolute reliability, and electrics make that possible.

Unless you have metal working capacity, you need to make a friend at a nearby Metal Mechanica, and find someone with a lathe. Also, start looking for a steel bike, dual suspension, and with a headtube for 1 1/8th. A hardtail can work, but definitely steel so it can safely be modified.

In the best case aduanas increases cost by just over 30% on top of what you pay for product and shipping.

 

[motomech]

It was the dogs that drove me crazy. Seems like many Ticos delite in watching them chasing extranjeros and nipping at their heels. It's part of their non-agressive agressiveness.
It was a dog that came though a fenced field and got tangled in my frt. wheel, before I had a chance to react. Broke my collarbone in two places and it was 24 ht.s before I could get a flight to San Jose.
It still hurts.

 

[induna]

So, some moderate progress, at least on the planning. It soon became apparent that batteries were going to be the problem for two reasons. First the new shipping rules apparently make it difficult or impossible to get lithium from the States. Paul is happy to ship from China, but then I would have to face the second problem, which is a very high import duty on batteries -- around 43%. (The rest of the items for the bike that I will have to have shipped should only be around 13% duty for the motor and bicycle parts.) So, I decided that it would be a lot more cost effective to build a pack myself from 18650 cells. So even if I have to pay the 43% duty, I will only have to pay it on the cells themselves, and not on the case, charger, labor, etc. I'm building a car battery spot welder, have ordered cell holders and nickel strips from China, and am just waiting to hear back from Tumich to get enough 18650 GA cells for a 13S6P pack, which will provide more than enough constant discharge current for my intended build, even if I go with the Bafang BBSHD. I want to keep my pack healthy for as long as possible, so buying more Ahs than I will need and operating the cells well below their max discharge rate seems like the way to go. The cells will probably take at least a couple of months to get here, so I have plenty of time to decide on a BMS and charger, and continue to try and track down a suitable donor bicycle. A trip to San José (yech) will probably be necessary.

Poco a poco.

 

[motomech]

What about Panama?
I wonder if it would be easier/less expensive?
Know anyone in David?
The CR/panama border is easy, no?

 

[induna]

What about Panama?
I wonder if it would be easier/less expensive?
Know anyone in David?
The CR/panama border is easy, no?

Well, the border is and isn't easy. There's a lot of Cubans and Africans trying to get to the US by traveling up the Ismuth right now, so security on the border is higher than normal and there are a lot of police around on the roads right now. On the other hand, I live about 10 k from the Rio Sereno crossing which is about as sleepy as you can get. I thought about the logistics of trying to go through Panamá, but I finally decided that the time, gas, and imposing on my very busy neighbor with residency in Panamá wouldn't be worth it.

Tumich is very reasonable, and his shipping prices rock. I might even get lucky and his package won't get sent to Canoas. Even if it does, I'll still end up with a great pack of quality cells for a good price. I'd rather pay 43% on $300 than on $700, since I'd have to pay the 40% on the shipping costs of the battery from China as well. Plus I get to work with another good friend building and programing the spot welder. You gotta look at the bright side.

Pura Vida.

 

[LewTwo]

You have at least one very valuable asset: a positive attitude.