DFD

Alright, some background first. I currently walk about a mile and a half to the train whenever I go into the office (2 days a week or so). It's nice to get out for a walk in the morning but often stretches my commute to over 2 hours. So I bought a fixie...something I don't feel bad about locking up all day under the weather.

So I got the bike this week and by Thursday I realized I needed modz. So I'm going to build my own e-bike.

E bikes come down to 3 main components...motor, controller, and battery. Of course there is a lot more to it, but those are the biggies.

Motor: 36V 600W brushed standalone unit (not a hub motor) that I'll likely push to 1000W peak with higher amperage. I also got it with a reduction gear to about 500rpms so I can just weld a freewheel sprocket to it and not worry about gearing. In theory.

Controller: something from china. I dunno, it's literally all in chinese but I gathered that it's rated for 800W.

Battery: I have 30x 3000mAh 18650 cells on order (fun fact, these are what was in teslas until they got their own "pad" type unit). I have some flexibility here, I'm assembling my own battery pack...shooting for 3 parallel x 10 series which should give me something like 36V and a little over 10Ah. I've also got a comparable battery pcb that I'll have to figure out (to protect the lithium cells from over/under dis/charge thresholds).

My thinking is that I'll pack the batteries, controller, and charger in a backpack (with venting) and have a plug that can connect to the bike. That way, the only thing mounted on the bike is the motor itself. I can also protect the cell pack from the elemenys and charge it while at work. It'll also be super clean. Wires will go through the frame, and I'll be implementing a super simple/clean braking and throttle situation.

There is going to be some fab work involved with mounting and stuff too, which will be interesting to figure out but that's why I've got a welder.

Anyways this should be a fun project for rainy days. Lots of parts coming in today, picture of cheapo bike below (I still need to put my bullbars, levers, and seat and stuff on)

Interesting. Will follow. My uncle is about to the the e assist mountain bike. They range $3-10k. He is a huge fan.

I see shit like this all over the city, mostly with delivery bikes. They zip around pretty damn fast.

Make sure the chain is 1/8" and the cog/chainring is strong enough for this type of power. I'd suggest a Surly cog. Most of the el cheapo bikes will come with soft steel cogs that will break/quickly deform under this type of power.

dubshow wrote:Interesting. Will follow. My uncle is about to the the e assist mountain bike. They range $3-10k. He is a huge fan.

Yeah those setups are usually insane and push crazy amounts of current through. All in I'm shooting for under 500 bucks. On those higher end ebikes the battery pack will be 3-5x that alone.

Johnny_P wrote: I see shit like this all over the city, mostly with delivery bikes. They zip around pretty damn fast.

Make sure the chain is 1/8" and the cog/chainring is strong enough for this type of power. I'd suggest a Surly cog. Most of the el cheapo bikes will come with soft steel cogs that will break/quickly deform under this type of power.

Ultimately I'd like to adapt a #40 chain to the hub cog and just run that (idk if i would be able to find something pre made) if the space allows. 25/eigth would be a bare minimum.

rockchops wrote: ↑Sun Sep 17, 2017 1:16 pm

Johnny_P wrote: I see shit like this all over the city, mostly with delivery bikes. They zip around pretty damn fast.

Make sure the chain is 1/8" and the cog/chainring is strong enough for this type of power. I'd suggest a Surly cog. Most of the el cheapo bikes will come with soft steel cogs that will break/quickly deform under this type of power.

Ultimately I'd like to adapt a #40 chain to the hub cog and just run that (idk if i would be able to find something pre made) if the space allows. 25/eigth would be a bare minimum.

Nice.

tagged. there was a YUGE ebike thread on miataturbo.net i followed. I really like the concept.

Cells and controller came in! Wasn't kidding about the. Chinese controller...

Big Brain Bradley wrote:tagged. there was a YUGE ebike thread on miataturbo.net i followed. I really like the concept.

Awesome! Gonna check that ouy. I haven't come across anyone doing exactly what I'm doing (or that close even), most go for a hack job on an old huffy or spend tons of money on serious hardware. Most use hub motors too...which I wish I could use but I can't find any for a road/track style bike (wheelset is too thin). Could spoke my own wheels I guess but that seems overkill. That and a lot of the guys Johnny refers to run lead acid batteries in saddlebags. Gross.

Hell, if this is clean enough I could probably find a market to sell conversions to.

sounds pretty cool, can't wait for results!

rockchops wrote: ↑Sun Sep 17, 2017 4:57 pm

Big Brain Bradley wrote:tagged. there was a YUGE ebike thread on miataturbo.net i followed. I really like the concept.

Awesome! Gonna check that ouy. I haven't come across anyone doing exactly what I'm doing (or that close even), most go for a hack job on an old huffy or spend tons of money on serious hardware. Most use hub motors too...which I wish I could use but I can't find any for a road/track style bike (wheelset is too thin). Could spoke my own wheels I guess but that seems overkill. That and a lot of the guys Johnny refers to run lead acid batteries in saddlebags. Gross.

Hell, if this is clean enough I could probably find a market to sell conversions to.

most people mount the batteries and brains in the triangle of the bike. Look Into it. It will make for better balance. Also easier to jump off a lithium fire vs having it strapped to you back. These guys also make it very easily detachable for charging at work and theft deterrence.

Big Brain Bradley wrote:

rockchops wrote: ↑Sun Sep 17, 2017 4:57 pm Awesome! Gonna check that ouy. I haven't come across anyone doing exactly what I'm doing (or that close even), most go for a hack job on an old huffy or spend tons of money on serious hardware. Most use hub motors too...which I wish I could use but I can't find any for a road/track style bike (wheelset is too thin). Could spoke my own wheels I guess but that seems overkill. That and a lot of the guys Johnny refers to run lead acid batteries in saddlebags. Gross.

Hell, if this is clean enough I could probably find a market to sell conversions to.

most people mount the batteries and brains in the triangle of the bike. Look Into it. It will make for better balance. Also easier to jump off a lithium fire vs having it strapped to you back. These guys also make it very easily detachable for charging at work and theft deterrence.

Yeah seen that too. I'll be compartmentalizing it all either way, but id rather not mount them on the bike. Also, these are lithium ion batteries, it's like 3lbs for the pack, so no issues with weight.