First Electric Bike Build

[Marcus_E]

Hello all!

I'm looking to build an ebike! Never heard of that, right? I'm 5'8 110 lbs, so a small guy, looking to build a bike that can do 30~35 mph in Tallahassee, Florida. While not as bad as San Francisco or anything its fairly hilly so I would like the bike to be able to deal with that. As for range 20 or so miles would be nice but I need it to be longer that 15 to do my commute and just going around town.

First off I will need a bike to convert. I would like to keep the entire build at ~2000 dollars so 500 bucks for a bike is my goal. I'm comfortable with searching craigslist in my area and keeping a lookout for a nice bike but I just don't really know what I will need. I have done some looking around but there are so many options and very little on what makes a good ebike conversion. Any suggestions for bikes/bikes + modifications? (Don’t worry I know more about the rest of the build from here on)

As for motors so far I am leaning towards either the HT 3525 or HS 3540 from http://www.ebikedeal.com/crystalyte.htm. I know the HT is High Torque = good hill climbing which would seem perfect but after running some tests on the sim at http://www.ebikes.ca/tools/simulator.html it would seem that except for a small percentage at sub 20mph the HS3540 blows the HT out of the water on all accounts. Even though hill climbing will be required the HS seems to be the better motor. Another consideration is in rim vs not. I would like something in rim as lacing doesn't seem like my cup of tea.
***EDIT***:I figured out why the 3525 was so lacking... the 25 bit of the model is for the max speed, 25 is euro legal at 25kph... It will deliver more range but less power because of the power cap. That helps narrow down the options. I think I will go with the HS3540 then.

The controller I have selected for my build is likely going to be the 12 x 4110 MOSFET Extreme Modder Controller LYEN Edition $129 (http://endless-sphere.com/forums/viewtopic.php?f=31&t=17683). It is optimized for 72v and 45ah (Would running under the ah matter too much? If so how much? More on why I'm asking in the battery section.) I also plan on getting a Cycle Analyst for my display. Will I need to do/buy anything special to make them play nicely and function together?

For the battery I'm not sure I'm ready to go full LiPo so I am planning on keeping it somewhat simple but still powerful with a 72v LiFePO4/Li-ion but I'm not exactly sure what to get. I do have a few ideas though.

1.First I have seen the CaliBike 72v 15ah (http://calibike.com/?product=lithium-72v-15ah-ultra-light-battery-pack) but the pack has a max continuous discharge rate of 30ah which is somewhat low compared to other options.

2.Secondly there is a pingbattery 36v 15ah LiFePO4s (http://www.pingbattery.com/36v-15ah-lithium-lifepo4-battery-pack/). I believe I could simply hook two of these up in series and use as is. They are a bit more expensive than the Cali pack but they have the option of up to 80ah discharge, while with the controllers I have looked at I should keep it under 45 it seems like the upgrade over Cali may be worthwhile. They will also come with a charger each so twice the charging power = half the time would be nice as well.

3.Finally, I could dive in headfirst and attempt to build my own with the Headway Lifepo4 units supplied by http://www.ebikedeal.com/lifepo4.htm. I am currently an electrical engineering student so it would be an interesting practical application of my learning, but I am only in my second year so I have yet to learn much about the specific aspects of batteries or circuit building( but calc II is fun so ). While I don't mind doing it this way unless the savings is significant I would be happier purchasing a ready made pack.

I believe that those are all the components I will necessarily need but there are a few extras I have looked at. First off a DD motor should be regenerative braking compatible and with the hills around me I can see ample opportunity of make use of it. The controller by Lyen mentions it but states that it would require some tinkering. That tinkering seems to be just connecting the correct pin?


The bottom line for this bike is while I would like it to be my main form of transportation it is also a pet project of mine. I have had a great time reading up on motors, batteries, controller, frames, and so much more. I would love to learn more so any extra resources I should look into would be welcome. I have read all of the FAQ's and beginners guides (for this forum to 'The Rant' by YPedel). Thanks for any help or recommendation you can offer, sorry this is so long and I can't wait to join your ranks.

P.S.
Oh yes last thing. Torque arms, will I necessarily need one, if so would just purchasing in from Lyen be perfect or do I need to make sure to get one compatible with the bike I choose?

 

[mlt34]

Welcome to endless sphere! You're on the right track for building your first ebike. Now let's get down to details.

looking to build a bike that can do 30~35 mph

30-35 mph is definitely possible, but it's not cheap and it's not necessarily even safe without the right bike. 30 mph is a better target, and more achievable with lower cost parts.

Either way, you'll want a nice steel frame bike. Front suspension will be important to keep your wrists from braking if you hit a pothole at 30 mph. Rear suspension is recommended at those speeds but by no means a necessity. It will just make the ride more comfortable. It also severely limits the usable space for batteries though, so I actually prefer a bike with nice front suspension but no rear suspension when I'm doing street commuting.

You should know that at 30 mph, you'll be using probably twice the amount of battery as you would at 20 mph, so you'll need a big battery.

Speed will depend both on battery voltage and the type of motor you get. The higher the battery voltage, the faster you'll go. The crystalyte motors you are looking at will do it, but I'd actually recommend a 9C motor since you don't need to be running high currents. A 2806 with a 25A controller and 48V20AH ping will get you 30 mph and a range of around 25 miles, likely more since you won't be doing 30 mph the whole time.

You mentioned rim vs no rim. Get a motor already in a rim unless you feel confident about your lacing abilities. It's not rocket science but it really is an art. If you don't get it right, you'll have to have a local bike shop do it for you, where it will cost a fortune and they might damage your motor.

Regarding that controller you mentioned, the controller doesn't care what AH the battery is. AH is just battery capacity: think of it like the size of your fuel tank. Perhaps you were thinking of amps, not amp-hour. Your amps relate to instantaneous power, so a 25A controller will give you less power than a 40A controller with the same battery. At cruising speed you likely won't notice any difference, but on hills and starting from stop signs/traffic lights you'll definitely feel the difference in the strength of the acceleration.

That 72V 15AH battery you're looking at will do the trick, and you could run a much slower wind motor. But those batteries will be much more expensive than a 48V pack.

Torque arms will be important. I like Grin Tech's torque arms best, but there are many styles out there. Just don't get the kind they sell all over china, they look like grin tech version 1 torque arms. There are much better out there, and even grin tech has said they moved past that design to much better designs.

You're on the right track, but you may need to re-evaluate your specs a bit to rein in what you want your first build to be capable of. I'm not training to rain on your parade at all, rather I want to make sure your first build is a success and serves as a good ambassador into the world of ebikes.

You can build a nice bike for $2,000 bucks, but you can also build a nice bike for cheaper. For example, my daily driver does 27mph and gets 25 miles range when I limit the controller to 15A via the Cycle Analyst. All the electronics cost me about $500, except for the Cycle Analyst. For reference I used these parts:
motor ($114): http://www.bmsbattery.com/ebike-kits/580-q11-48v1kw-front-driving-hub-motor-e-bike-conversion-kit.html
controller ($18): http://www.bmsbattery.com/controller/363-universal-brushless-hub-motor-controller.html
battery ($190): http://www.bmsbattery.com/48v/166-48v-10ah-lithium-ion-electric-bicycle-battery-pack.html

I have no hills to deal with, so you might want to upgrade to the KU123 controller, or even KU151. At that level though, I'd also upgrade to the high-c rate battery, which is only like $20 more. Shipping is expensive from them, but the prices are so cheap for everything else that it's still worth it.

Good luck with whichever way you choose to guy. Keep us updated.

 

[wesnewell]

Before you go wasting all kinds of money on shipping from China, check out all the kits available in the US with free shipping, no waiting, and legal recourse if there's a problem.
http://www.ebay.com/sch/i.html?_from=R40|R40|R40&_sacat=0&_nkw=48v+1000w+rear&rt=nc&LH_PrefLoc=1

 

[Marcus_E]

Before you go wasting all kinds of money on shipping from China, check out all the kits available in the US with free shipping, no waiting, and legal recourse if there's a problem.
http://www.ebay.com/sch/i.html?_from=R40|R40|R40&_sacat=0&_nkw=48v+1000w+rear&rt=nc&LH_PrefLoc=1

What am I shipping from china?

I believe at least two of the batteries are US based (the exception being ping). The motor + rim is US based or at the least the best price I have seen as well as free shipping and the controller is also US based + free shipping.

Ping seems to be reputable. I found them through the "Top battery retailers" thread. Any specific recommendation to skip them? I have seen several cheaper batteries on Ebay but they are either only a couple of bucks off or they have 8+ week shipping. While this is tempting I would also like to have the higher discharge rate that Ping offers with their upgraded BMS.

Though looking a bit more I have found this seller ( http://www.ebay.com/itm/NEW-36v-15ah-LiFePO4-Battery-5A-Charger-BMS-Ebike-Kits-Powerful-Sea-8-Weeks-Gift-/131225660075?pt=US_Rechargeable_Batteries&hash=item1e8da8aaab ). While the battery will not arrive until thanksgiving it is a good chunk of change cheaper.

Would I be able to hook them up in series and use them as a 72v battery or will the BMS cut me off?


edit:
and yes I see the irony that you suggested I buy from America and I found another battery from China.

 

[spisska]

Your goals are definitely achievable, and within your budget too. So that's great news.

Here's a picture of my bike, which was about $2k all-in, including some rookie mistakes that added a couple hundred dollars to the cost that I could have avoided. My bike tops out at about 28 mph, and has a range of around 40 miles:

The bike frame itself will be a relatively minor part of the cost, but is critically important. The ideal e-bike frame is steel and has mounts for disc brakes both front and rear. Steel, because it won't shatter like aluminium and carbon fiber under stress, and disc brakes, because an ebike is heavier and faster than a traditional bike.

Unfortunately, an affordable steel frame with disc-brake mounts is unicorn-level rare. You can reach a compromise by replacing a stock fork with one that will take a disc brake, which is what I did. But I highly recommend you use a suspension fork -- I didn't, and my bike requires an extreme level of a care when running at top speed.

I would also say that while people here have successfully built bikes out of aluminum frames, I can't recommend it. I've seen enough people break aluminium frames on traditional bikes that I wouldn't even consider one for an ebike, even with a perfect solution to counteract the torque of a hub motor, or even with a mid-drive, where torque on the dropout isn't a concern. Maybe you'll never have a problem, but do you really want to discover the limit of an aluminium frame while going 30 mph on a Florida back road?

Another thought, because your budget is realistic: you can save a couple dollars by buying your kit piece-meal from different vendors, but if you get all of it from one shop, they'll give you all the right terminations for all the right pieces. Meaning mount, plug, and ride, with no fussing about with sourcing your own connectors.

I would also recommend avoiding LiPo/LiCo batteries. Yes, lots of people run them without problem, and yes, they do give you the greatest amount of power in the least amount of mass. But would you rather have a battery that won't explode, or one that *probably* won't explode as long as you treat it in exactly the right way?

I would also absolutely recommend a torque arm, torque plate, or other solution, assuming you're planning a hub motor. And for simplicity's sake, I would do a hub motor before any of the more esoteric options.

In summary, if I had $2k to spend on another bike, I'd look for:

* a strong, steel frame

* a strong suspension fork with disc-brake mounts

* a rear-mounted hub motor

* a frame-mounted battery pack -- this is heavy, and you want it mounted centrally and low to give you a good center of gravity. I see bikes with batteries mounted on a rear-rack over the back tire, and I shake my head ...

* I'd buy my entire electric kit, battery and all, from Paul @ em3ev.com. He's not the cheapest, but his service is excellent, and he will save you a lot of trouble and heartache just from how he properly terminates all the lines.

One more thing: Get the Cycle Analyst V3. There is nothing that comes close in telling you what your bike is actually doing, and nothing that comes close in allowing you to control exactly what your bike does.

 

[Marcus_E]

Any recomendations for a good steel frame and disc brake compatible fork? Will I also need to do something to make sure the back is also disc brake compatible?

I'm looking for something with 26 inch wheels.

 

[dogman dan]

Very hard to suggest a particular bike. So many are suitable.

What's not so suitable, is wanting to run 40amps of 72v immediately. Lots of pitfalls, even with a front shock. Ever done 40 mph, and stood a bike on the front wheel at that speed? You will when you hit the right manhole cover.

Some build motorcycle fast bikes immediately and get away with it, but generally they spend more on the bike. Limit hard tail bikes to about 30 mph except on routes you know have no surprises.

Here's my suggestion. Get this. http://www.ebikes.ca/shop/conversion-kits/direct-drive/crystalyte-rear-hs-kit-basic-throttle.html

Select the motor you like best, and upgrade the controller to 36-72v 40 amps. Get two of the torque arms.

Now you have the motor you liked, and you can spend more gradually on batteries and bikes. You can start out with a much more affordable battery, and set the Cycleanalyst to less amps so you don't ruin a cheaper battery in weeks. I'd suggest starting out with something in 48v 15 amp hours, and set the CA to limit amps to 25-30 amps. This you can run on a relatively cheap bike, a steel or alloy frame hardtail with front shocks. Look for 1 1/8 headset only, so you can put a better shock on later if you want to. Stick to 30 ish mph cruising with the hardtail, even if it will do a bit more. No need to pay more than $300 for that bike, even brand new. Disc only on the front will be ok, but both disc ideal. Just avoid alloy frame bikes that sell for less than $300 brand new. They have weak bendy frames. But a cheapo steel frame can be very stiff.


Then later, when you can afford batteries that can take 40 amps and last, you can upgrade to more amps. Also, you can upgrade to more speed at some point, when you get a good full suspension bike. Wait to buy that bike, till you know a lot more about what to pay for what. It might be a year, or it might be weeks, but ride around some on a cheaper bike before you dive into a much more expensive FS bike for hauling ass.

BTW, a 48v 15 ah battery will have 22 miles range at 25 mph. So you will have enough range at moderate speeds, and 15 miles at about 30 mph. It's a good place to start, then later you can decide how much cash you want to dump into faster.

At 35mph, you'll double the battery it takes, lots of money and lots of problems with carrying enough battery to haul ass 20miles. Fun as hell though, to haul ass for 10 miles on rides that aren't commuting.

 

[Marcus_E]

Ok, cool.

You're recommendation is pick up a good 48v now and see how that rides I can always pick up another 24v or whatever to get myself up to 72v if I feel its necessary.

Then instead of parting everything out just stick to ebike.ca because they have decent prices and a great reputation. Get the same motor from them but also grab their controller and CA(which I was planning on anyway).

As for a bike just go to a bike shop and check out a few cheap front suspension steel framed bikes and preferably have disc brakes. (What about installing my own disc brakes? Would it be challenging with the crystalyte motor and is there anything in the bike itself that I need to have to be able to install them?)

All that looks good. Starting out a bit cheaper with the ability to relatively easily upgrade in the future. My only other question is if I go with a CaliBike 48v 15ah will I be able to hook it up in series with a 24v later or will the BMS limit me? (http://calibike.com/?product=electric-bicycle-ebike-48v-15ah-lithium-li-ion-battery-and-charger)

 

[spisska]

What about installing my own disc brakes?

The issue is the mounts. There are a couple aftermarket mount adapters, but they all look pretty sketchy to me. You could of course weld on your own mounts, but that's a whole other project on its own. Either way, brakes are not something you want to skimp on.