Building a ebike for a small person with a budget of <$700

[GamzNadir]

Why an ebike? At your price range, you'd be much better off focusing on a good analog bike, new or used, and worrying about adding power later.
There are few good parts that you can buy for a conversion within your budget, especially ones that will last two or more years...especially if you can't do the work yourself and need to pay someone, say to build the rear wheel with the hub motor.

I have a lot of reasons for wanting an ebike. Mostly medical, can't actually use a normal bike to be honest. Trust me, I would have waited till I had more money if I had that choice.

I am switching to converting a bike instead of outright buying one since I do realize that is the best option for my budget, just took a bit of a push from ya'll to even realize that was an option I could do.
That being said, I could build everything myself. Depends on factors, otherwise I do have a friend who can probably do most of the work for free or for a lower cost then a shop. I've already found some stuff, just need to do more research since, as already stated in other posts, I'm not making any final decisions till the middle of May. I'll just be disassembling and cleaning the bike I'ma use for conversion, plus continuing to learn about this stuff, I like to be well informed before anything.

Plus, having an excuse to sit outside all day several days a week to work on a bike seems way more fun then just buying it pre-made with little to no customization options.

 

[retiredNH]

I have a lot of reasons for wanting an ebike. Mostly medical, can't actually use a normal bike to be honest. Trust me, I would have waited till I had more money if I had that choice.

I am switching to converting a bike instead of outright buying one since I do realize that is the best option for my budget, just took a bit of a push from ya'll to even realize that was an option I could do.
That being said, I could build everything myself. Depends on factors, otherwise I do have a friend who can probably do most of the work for free or for a lower cost then a shop. I've already found some stuff, just need to do more research since, as already stated in other posts, I'm not making any final decisions till the middle of May. I'll just be disassembling and cleaning the bike I'ma use for conversion, plus continuing to learn about this stuff, I like to be well informed before anything.

Plus, having an excuse to sit outside all day several days a week to work on a bike seems way more fun then just buying it pre-made with little to no customization options.

Makes a lot of sense then.
Good luck, and let's hope it works out for you. DIY can be a lot of fun, and a great way to learn more about bikes and electronics. Do focus on safe practices, though, since the bike electrics pack a big punch. These batteries are NOT like flashlight batteries. They can be dangerous (fire and shock) if mis-handled.

 

[indianajo]

Making or installing the brackets to mount the controller, the battery, and the torque arms (important) is the hard part of a conversion. If the motor shaft doesn't quite fit in the axle slot, you can grind it out a little with a drill motor, a 3"x1/16" grinding wheel on a 3/8" mandrel (NAPA or mcmaster.com or grainger.com). Use safetyglasses with power tools. for controller I mounted under the seat with spam can lids & #10 SS screws.
The wiring, you just match the colors, mostly. Might have to buy a crimp tool and crimp on some dorman connectors: ring terminals, bullet terminals, or insulated flat terminals. I use Klein or Ideal terminal crimp tool. Others don't have enough leverage unless you're the Hulk. Pull test crimp termianls before use. I haven't had any reliability with XT60 or XT90 terminals. If I get them hot enough to stick to #14 wire the pins melt the block and move. Andersn battery connectors are reliable but I don't have a US source. You might have to buy a little #14 wire for the battery wire extension. Pointing the connector ends down of controller & battery plus drip loops of the wires can keep rain out of your controller & battery.
Installing a PAS pickup on the crank requires a special puller for a 3 piece crank, or a lot of custom work on the 1 piece crank on my Huffy Savannah. None of my six auto+industrial pullers has ever been able to get a crank arm off a 3 piece bike. I hated PAS so much when I moved the motor & battery to the yuba bodaboda I abandoned the magnet wheel on the Huffy. I just tied up the PAS pickup to the back wheel strut & ignored it. I use the throttle only.
Watch rim brakes in the rain. They lose 3/4 their stopping power after you run through a puddle. Disk brakes are a whole lot better, but the bikes with them on the used market are pricey. Short people like me don't have much choice but kiddie bikes: the hobby is dominated by tall people, at least here in Indiana.

 

[m@Robertson]

@GamzNadir when you said the bike needs to carry 200 lbs... did you mean total with you included, or you plus another 200 lbs? If the latter, that means the bike has to be able to handle 300+ lbs and that puts you completely out of normal bike and squarely into cargo bike territory. A regular bike can't take that kind of extra load without going to a trailer. A cargo solution is a better one.

This is a little premature for me to link to but something you can watch over time. I'm dropping the third installment tomorrow. It'll be complete perhaps at the end of the month of May. Also check the table of contents for discussions on cargo bike types and their relative strengths/weaknesses. And lots of stuff throughout on ebike builds. For a budget build look at the Mongoose Envoy where there's a specific page on budget build configs.

How To Build An Ebike From Scratch

You want to build an ebike, but the project seems overwhelming. Lets de-mystify the entire process, including planning, parts and perfecting the end result.

talesontwowheels.com