Standard Help me build an Ebike thread

Joined
Nov 19, 2017
Messages
14
Location
Texas, USA
Desired Max Speed on Level Ground: 40mph
Desired Max Range at 40mph: 40mi
Rider Weight: ~170lbs
Terrain: Probably mostly flat, anything that would let me measure this would be great
Budget: As cheap as reasonable. I'm thinking under $1k for sure but I'd like shoot cheaper if I can.

As to the bike I'd convert, I have 3 options. Try and convert my road bike, try and convert a cheap steel frame Walmart bike I have that has 26" wheels but no shocks of any kind, or buy a cheap bike to convert from somewhere.

Also I'm not sure if my speed and max range are unrealistic. I've been messing with the simulator on ebikes.ca and it seems like I might have trouble hitting my goals but I'd like to talk to the community first because I was mostly just shooting in the dark on it.

I'm hoping to make this into a daily commuter bike. I live about 10mi from my work and I'd like to be able to get there in under 30min with time to spare for any stop lights, busy intersections or just plain running late. So at minimum I think the bike should be able to go 30mph, but I liked the idea of being able to cruise at 40mph on level ground.

As for the batteries, I'm planning on doing a custom power build with 18650 cells that I've been salvaging. I have a 3d printer in the mail that I'm hoping to use to make a large custom case to fill the triangle of the bike with all the power gear (batteries, controller, charger, etc.)

Sorry if this is a typical newbie post, that has super high expectations and a super low budget. I hope to have my ideas tempered here, so hopefully I'll still be able to build a ebike that I will be happy with.
 
40 mph for 40 miles for $1000????(including the bike)
Yeah, that's a pretty standard "pie in the sky" Dreamer's first post.
Search wesenwell's posts to see what can be done for $1000.
He does a WallyWorld mountain bike WITH suspension with a universal 48V DD 1000 Watt hub motor and LiPoly batteries to get to 30 MPH.
Going any faster takes cubic $$$$ and frankly, IMO, is just insane.
Even 30 mph for any distance takes some serious batteries and I doubt you can get enough power in a reasonable size package w/ used lap top round cells.
How about filling out your profile
 
I can understand that 40mph is probably outlandish, and I'm willing to temper that back. 30mph should still get me to work in time.

However, I'd like to keep the 40mi range on the table. I really want the flexibility to travel around my work area without any worries about charging in between stops if I can't find a plug-in.

You may be surprised what I've seen built with these 18650s and I have been finding some pretty decent cells. I figure the pack will take awhile to find the best I can since I know that the size and weight will be an issue but so far finding packs to harvest ones seems like it won't be an issue for me.

Also if you could link his posts that would be great, I'd love to give them a read through to help me gauge my limitations better and get a more grounded view of things. I've been having some difficulty navigating the forums for what topics would get me on track.
 
HobbyKing Lipo battery, go 60V or 72V and 20-25Ah
HobbyKing Charger and psu

3 Turn Leafbike 1500W kit with KT display

That is all you need.
 
markz said:
HobbyKing Lipo battery, go 60V or 72V and 20-25Ah
...
3 Turn Leafbike 1500W kit with KT display

I'm planning on using some re-purposed 18650s, so I'll have to reconfigure them but I could hit those goals.

The 3 Turn Leafbike, I'm a little more shaky on do you have a good link to its specs and info on other builds? I'm checking out probably the main Leafbike motor thread now but it's like 30 pages long so it'll take awhile for me to parse it and I'm a little uncertain of how the turns work.
 
I'm gonna pretend you didn't say anything about 40mph.

To sustain 30mph on flat ground, you'll need at least 1250W continuously from the battery. So you'll need 1-1/3 times as much to go 40 miles at the same speed, plus a margin to deal with slopes, headwinds, and to keep your battery from getting fully discharged on a regular basis.

About 1650 watt-hours covers your mileage, on flat ground with neutral wind. In the real world, you'll be looking for 2kWh worth of battery, or more. That's 28Ah at 72V, or 42Ah at 48V. So you're looking at more than a grand worth of value priced commercial e-bike packs before you have a motor or a bike.

You can choose to make your budget by buying garbage quality components and salvaging cells, but then you'll blow your budget by buying stuff over and over again as things fail to work the way you hoped.

"Daily commuter bike" implies a certain minimum reliability threshold. Wally World bike, plus hokey Chinese eBay motor, plus homemade battery composed of random used cells, don't add up to that level of reliability-- at least not without months or years of troubleshooting.
 
Leafbike 1500W motor is the same size but lighter as MXUS 3k, either is a great choice.
A 3 or 4T motor gets you your speed, but you will be high on the throttle, eating up Ah's.
This happens to be up in a tab, trying to figure out my circumstances, its a 4504 MXUS 3kw
http://www.ebikes.ca/tools/simulator.html?bopen=false&motor=MX4504&batt=cust_58_0.2_12&mass=181&hp=0&cont=C40&throt=65&grade=2&blue=Lbs&black=load&frame=road
Look carefully at the selections I made and play around, I am sure your choice is not 400lbs, also throttle position for 33kph, those are reasonable speeds requiring reasonable battery size.
 
Chalo said:
You can choose to make your budget by buying garbage quality components and salvaging cells, but then you'll blow your budget by buying stuff over and over again as things fail to work the way you hoped.

I'm getting all the cells for free, so blowing the budget on the batteries isn't much of an issue. I've already tested almost 400 cells and have found quite a few good ones.

Also while I may want this as a commuter bike, I still like tinkering and building. If that means that I have to replace packs of batteries that have died that's fine. Now the frame, motor and electronics remain.

I've been recommended the Leafbike in this thread that sells for ~$350 with motor + electronics and seems popular/well regarded in other threads. That seems like it should be a quality motor based on what I've managed to read so far and would leave $650 for the frame and any electronics upgrades. I realize $650 isn't enough to get you the best bikes around but I read in the "proper advice" thread that steel frames are typically recommended and are conveniently of the cheaper variety of bike. I've also mentioned that I do have a few bikes already that could possibly be used if a suspension isn't 100% necessary.

I appreciate you trying to push me towards more standard batteries to use, they would give me more consistent performance and would be way easier to build around. However, I like the idea of trying to salvage batteries and keep the good ones from going to waste. I'd be doing this anyways for other projects I plan to use them for, so I might as well integrate them here if they can possibly save me over $1k in e-bike packs.
 
Ok, ebikes are my hobby and I spend a lot of time on them, so if you want to invest the time to test cells and build packs, I can see that.
But I need to point out a few things.
Going 30 mph will take one Ah per mile.
Going 25 -28 mph will take one Ah per 1 1/2 miles.
So, if you are dead set to do 40 miles at 30 mph, you will need 40 to 50 Ah's of battery.
Have you calculated the size and weight of your DIY pack and have you thought about where it will be placed on the bike?
Just to set the record straight, the Multistar LiPoly from Hobby King, when bought on sale, would be $500 to $600 delivered and the pack would be 2/3 rd.s the weight and size of the round cell pack.
At any rate, while the Leafbike and MXUS motors are great, you can get to the fastest speed your batteries can get you w/ the $150 Yescom 1000 Watt DD motor kit that I recommended. So if you want to stay on budget, you might want to check out wesenwell's posts(Or search Yescom. DD). He goes into great detail(too often, some might say) on how to build the exact bike you described in your first post.
 
motomech said:
But I need to point out a few things.
Going 30 mph will take one Ah per mile.
Going 25 -28 mph will take one Ah per 1 1/2 miles.
So, if you are dead set to do 40 miles at 30 mph, you will need 40 to 50 Ah's of battery.
Have you calculated the size and weight of your DIY pack and have you thought about where it will be placed on the bike?
Just to set the record straight, the Multistar LiPoly from Hobby King, when bought on sale, would be $500 to $600 delivered and the pack would be 2/3 rd.s the weight and size of the round cell pack.
Very fair points and I understand that these cells are going end up larger and heavier. I'm hoping that them being free will offset the disadvantages at least in my pocketbook's mind. Also I'm hoping building a large 3d printed mount can make it easier hide the bulk and/or put the batteries in an optimal space saving arrangement (Hexagonal close packing FTW). I'm even considering putting more in packs attached to a rack on the back.

motomech said:
So, if you are dead set to do 40 miles at 30 mph, you will need 40 to 50 Ah's of battery.
BTW, if it helps put your mind at ease. I have ~100 cells with over 2Ah of capacity (a portion are over 2.5Ah). So I have approximately 740Wh of batteries, which puts me at almost being able to make a 48V 15Ah battery pack.

motomech said:
At any rate, while the Leafbike and MXUS motors are great, you can get to the fastest speed your batteries can get you w/ the $150 Yescom 1000 Watt DD motor kit that I recommended. So if you want to stay on budget, you might want to check out wesenwell's posts(Or search Yescom. DD). He goes into great detail(too often, some might say) on how to build the exact bike you described in your first post.
I've been trying to search wesnewell's posts (note: It's spelled Wes Newell not Wesen Well, not trying to be rude but it could mess up other new users), however, I've had trouble finding his topics and not just his replies. Searching replies is like looking for a needle in a haystack; so I was trying to find more posts about his builds and thoughts by searching by his started threads but the search function doesn't have anything for that.
 
Well, it turns out the thread I was thinking about just popped up right next to this one;

https://endless-sphere.com/forums/viewtopic.php?f=4&t=41170
 
When planning on capacity I try to use diminished capacity (i.e. the battery capacity at the end of life) and my rule of thumb is 1 Ahr per mile at 20-25 MPH (but I might be a bit conservative depending on various factors .... pedaling, load, speed, etc).

One thing no one has mentioned is to break up those packs. Instead of one 30 (or 40) AHr you might want to consider several modular 10 Ahr packs. Thus you do not always have to be running a full load. Shorter trips might only require 1 pack. Also if one pack of you recycled cells goes belly up then you still have the remaining packs in service until you find and replace the problem child.
 
Three months ago, I was pretty much you today. I'm still a newbie, but I have some experience in having ridden 1300+ miles on my ebike in a few months going to work and back. Here are some thoughts based on my limited experience.

I think that riding 40mph consistently on a standard upright mountain or road bike is fundamentally unsafe due to the limitation on braking caused by the high center of gravity. 30MPH is marginal. I think that if you want to go at sustained high speeds you need to stretch a bike frame and/or lower your center of gravity. Basically, you are building a motorcycle. "Doing that right probably blows your budget.

You say that you want to get to work in under 30 minutes and have 10 miles to travel. Well, I commute 16 miles and a fast trip to work is 45 min., a fast trip home is about 50 minutes (a bit more uphill and night riding going home) and a slow ride is 55 minutes. My typical speeds are in the high to mid 20s. I have sections that I cruise at 25mph and some downhill sections. where I'll hit 40mph and cruise at over 30mph for a mile or so. I have stop signs and stop lights, but also mile long stretches with no traffic control. My average moving speed is about 22.5mph on a fast ride with an overall average speed of a bit more than 20 mph. Here's a recorded track of a typical fast ride into work. The graph shows my speeds and you can also see speeds on the Map section.

http://www.sportstracklive.com/track/detail/wturber/Cycling/Commute-work-/ebike-/2378760#/altitude
So I think you can reach your commute goals by going a little bit faster with an average moving speed a bit closer to 25mph and an overall average speed of around 22mph.

I carry about 1100 watt/hrs of battery and have no problem with my 32mile round trip without recharging. I run 36v packss charged to 41v and my voltage when I get home is usually just a bit over 36v. I estimate that I use a bit less than 25 watt hours/mile and that I use a bit more than 2/3s of my pack capacity. I do put in some real pedal effort. In fact, I broke a chain yesterday. That helps a little (not as much as you might think) with power consumption and speed. I recently did a slower paced round trip of 42 miles to a friends house and had battery to spare when I got home. That's something to keep in mind. If you want to stretch range, just slow down a bit.
My knowledge of motors is limited. I bought a cheap ebay kit (9C style motor with controller, built wheel, tire) for under $250. I did this largely on the strength of a YouTube video of a fellow who has put around 10,000 on a similar build. I wouldn't hesitate to consider the Yescom motor someone else recommended. Even the really inexpensive hub motors seem to be pretty reliable if you treat them reasonably well.

Don't forget to include the cost of a good battery charger, wires and other miscelaneous stuff. You should probably budget for some high quality tires and/or liners. Consider also the costs of upgrading your gearing if you intend to pedal along. You'll need higher gearing. Which means an 11 tooth freewheel or cassette and probably a 52T chainring . Then there's lights if you are commuting at night and you may want to consider things like racks and baskets for carrying stuff, as well as tools to complete the build and things like power meters so you can monitor what the heck the bike is doing. The misc. stuff can add up fast. Don't expect to save money vs. driving a car. Though you might come close to breaking even.

If you accept more modest speed expectations, plan carefully (avoid buying stuff twice), shop smart, and find the right used bike as a base to start, I think you can probably meet your target budget and commute times.

I would add that if you are fit and willing to put in a lot more physical effort, a light road bike approach might actually work better for you. There are a couple good threads on that approach. One is currently active.
 
You're more than likely going to be building more than one e-bike. :lol: Like most things... "buy nice, or buy twice." Most of the people have been where you are and spent grips of money learning range + speed = probably double what you expect or want to spend.

Under a grand is not a whole lot of money to get the range you're asking for. A guy that rides with me on the train uses a road bike with a 250W geared hub. I don't know what his battery set up is, but he has it in a small triangle bag. He's able to maintain 30 mph, but I've never asked him what his range was. He probably spent less than a grand, but I'm assuming, based on the size of his battery pack (also Chinese 18650s he swears are good quality) he probably gets 20-30 miles @ 20-25mph.

You should consider is charging at work if that's possible. Of course you'll need two chargers, but you can carry a less cumbersome battery.
 
Jacob's Ladder said:
I've been trying to search wesnewell's posts
I'm not sure what you're trying to find, but most of what you need to know is in this post.
http://endless-sphere.com/forums/viewtopic.php?f=3&t=66302
I just added some info about battery sizes required the other day.
 
I know I've disappeared and left this thread dead but my project is still ongoing and I've been doing some thinking.

I recognize unless I buy nice, I'm going to eventually end up buying twice, as said before but I think it's foolish for me to head into this too hardcore because as also pointed out, I don't have a solid foundation for understanding what I'm in for.

So I'm thinking that I'll go with a cheapy Ebay kit and try using one of the bikes I have on hand until I find a good deal on an upgraded frame.

So I think my last question for now is going to be should I get this kit with an LCD display or should I get this one without a display for much cheaper and buy a separate one? I don't even know what display would work with this kit for certain.
 
If you have a multimeter, a timepiece, and some way to measure distance traveled (e.g. a phone app), you can get all the data you need to tell you what the controller's display will tell you. It just won't be conveniently at your fingertips.

Many of us, myself included, started doing this stuff before anyone thought to provide an information display. I started without using components that were designed to work together. You can learn a lot that way, but it's not clear that the rewards would be very useful anymore.

If you really want to hack together a test mule that you are certain to replace quickly with something better, I don't see any reason not to go as cheap and simple as you can. But don't skimp on the battery. Assume you'll be taking that with you to the next bike.
 
Chalo said:
If you have a multimeter, a timepiece, and some way to measure distance traveled (e.g. a phone app), you can get all the data you need to tell you what the controller's display will tell you. It just won't be conveniently at your fingertips.

Many of us, myself included, started doing this stuff before anyone thought to provide an information display. I started without using components that were designed to work together. You can learn a lot that way, but it's not clear that the rewards would be very useful anymore.

If you really want to hack together a test mule that you are certain to replace quickly with something better, I don't see any reason not to go as cheap and simple as you can. But don't skimp on the battery. Assume you'll be taking that with you to the next bike.

Good point, I have all those things and I'll probably want to have a phone mount anyways, so I can just use it as a meter for that sort of stuff.

Yeah, I think this guys is going to be a Gen 1 bike. I'll ride it until she gives up the ghost or until I get fed up with something about her and then build a Gen 2. The batteries will just be my salvaged 18650s for the first one (free is hard to beat and it's an interesting hobby) but we'll see about the next one; I'm up to ~180 cells tested at more than 2Ah btw :D .
 
The only thing I have for a display on my road bike is an old CatEye style speedometer. The other bike has the full display but the information I really want (remaining battery power) is totally bogus. For that a voltmeter works much better.
 
The one with the display worth its money. Not for the not worth shit battery meter though, but for the other functions, such as speed limiting and the on off switch.

Speed limiting,, ha ha.. :lol: But later on you might find you want to go farther, and the ONLY way to do that with a limited size battery made from shitty free cells is to slow wayyyyyyy down.

Heres the bargain deal on a volts display, for watching your battery, that you need with either kit.

https://www.ebay.com/itm/Durable-LED-AC-60-500V-Voltmeter-Two-wire-Digital-220V-Voltage-RED-Meters-CA/292367833027?hash=item44127b17c3:g:iPkAAOSwTO9aMIzA

If you really buy into this with big money, then you will want a cycle analyst for your display. 40 miles at 40 mph is not expensive on the motor side, but its big bucks on the battery side. You'd need about 72v 40 amp hours. Couple thou potentially, on battery and charger.
 
dogman dan said:
Heres the bargain deal on a volts display, for watching your battery, that you need with either kit.
https://www.ebay.com/itm/Durable-LED-AC-60-500V-Voltmeter-Two-wire-Digital-220V-Voltage-RED-Meters-CA/292367833027?hash=item44127b17c3:g:iPkAAOSwTO9aMIzA
Only if one is using a really long extension cord: Measuring Range: AC30-500V. :p

as an alternative a link to this was posted in another thread:
file.php

but it does not seem to be listed at this time .... :(
 
why not one of these, it has pretty much all the info you need.
https://www.aliexpress.com/item/Battery-Tester-TK15-High-Precision-LiFePO-Lithium-Lead-Acid-Battery-Testers-Coulomb-Counter-50A/32823138463.html?spm=a2g0s.8937460.0.0.YfcV9h
you can move it bike to bike and not have to have 48+v supply next to your fingertips
 
https://www.ebay.com/itm/0-56-2-Wire-LED-Digital-Voltmeter-DC-Voltage-Meter-Tester-Panel-Waterproof/302558466885
 
On my phone, not easy to search thing up, but you can fond Evolution GTS telling of his developing 40+mph bikes with things like yescom. Having 1000w in that and Leaf, I can say they're much the same a and therefore if yes com ever does get a 1500w it shouldn't be any better than this.

http://m.leafbike.com/mobile/products_detail.php?ProId=987

Before you pick a bike, see about riding down a steep hill with real speed. I thought 1500w. On the OCC Chopper was going to be kewl, but that thing is too unstable. XGames bikes feel like they'll pitch you over the bars on a bump, no matter how much they look like motorcycles don't fall for it.

Once you decide you like the bike, think about better brakes. And a better fork. You can reach 40mph but not stay happy with it. You won't feel bad if you spend more on it later if it seems like it'll work out by then.
 
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