Dirt Cheap DIY eBike

[RebelRider.Mike]

I spent some time refining the gadgets I'll have on the ebike, and how to wire them up:

I've decided to add an old bicycle headlight I fixed up, though I won't be powering it from the main battery. I also found this cool dual display, dual probe temperature gauge. I'll use it to monitor the temps of the motor and battery box while I ride.

Yay, more video:
[youtube]abJRPNDRlP0[/youtube]

Seems the motor and battery are the vast majority of the work on this bike. I'm back on the motor, fitting a freewheel cartridge and a roller bearing. Also a couple miscellaneous things. I've actually got a lot more footage to go through. I intended to make a final motor video ending with it on the bike and running, but that would have been way too long. But I'll give you a spoiler: The motor is on the bike and it (mostly) works!

 

[RebelRider.Mike]

Finally got the motor mounted to the bike:
[youtube]u_GqLNlEjA4[/youtube]

 

[wturber]

The driven sprocket on the wheel seems to be wobbling in the video - like it isn't square to the hub. That may be the main cause of the chain skipping. There may also be some flexing of the rack that the motor is mounted to. So anything you could do to make that more rigid might help. And finally, adding washers or shims to fine tune the distance between the motor and the drive sprocket might also help by letting you make small adjustments to the chain slack/tension.

One last note. You may want to test how hard it is to throw your leg over that motor when you mount the bike. Adding the milk crate to my bike forced me to change my standard motion. I now have to hitch my leg up and drop my knee down as I swing my leg out - sorta like a high jumper clearing the high bar - in order to clear the milk crate and get over the seat.

 

[RebelRider.Mike]

Refurbishing my motorcycle has slowed down a bit because of winter weather. I may work on the eBike again.

I made this video a while back, but forgot to publish it. It's basically a lecture on how I'm keeping my battery safe. For all you folks who already know about safety features, this will probably be really boring. But for anyone considering building a battery and you're interested in making it relatively safe, I hope the information is helpful.

[youtube]FVh0LujOCk4[/youtube]


Not every battery would need these features, and some batteries may benefit from features I've not included here.

 

[RebelRider.Mike]

Thanks. I totally forgot that I started a thread here! It's been a while. I ended up re-thinking the battery after I got a really good deal on some lightly used cells. I found 128 cells that are all the same make and model 18650, and have slightly better specs than your average laptop cell. Though some of these did come from old laptop batteries, so the title of the thread is still valid I think, LOL.

Anyway, I actually got as far as taking the bike for a test ride, and it did ok, but the motor is using more current than I anticipated, and keeps tripping the BMS. At least I know it's doing its job. I'm not on my computer now, but when I am I'll share some specifics and pictures of my progress later.

 

[RebelRider.Mike]

Shoot! I just realized I have two threads for the same project here.
The other has more recent info, but it's still out of date. Regardless, let's use that one moving forward and consider this one dead. Here is a link to the better one:

https://endless-sphere.com/forums/viewtopic.php?f=6&t=97199

 

[amberwolf]

I can merge them for you if you like, to keep all the info together.

 

[RebelRider.Mike]

That would be great if you have time.

 

[amberwolf]

Done.

 

[miro13car]

reclaimed old laptop batteries
I tested some on CBA tester and in the best case they would deliver at most 80% of rated capacity written on the battery case
I agree carring the extra weight of worn out cells is not worh it.
beside try to find laptop battery with 3500mAh cells.
very unlikely
but on other hand delaing with fake Aliexpress cells???

 

[floydr]

In the past 3 years, there has been LG M26 2600mAh 18650's, LG mj1 3100mAh 18650's ninebot scooters?
The M26 cells test good both capacity and IR this I know personally having tested 2000+ cells. ave. 2500mAh ≤42mΩ
The MJ1 cells I have heard test good in both in capacity and IR.
iirc these are both 10A max discharge cells.
later floyd

 

[MxusMick]

I have been salvaging motors from junk and know I few tricks. The washing machine motor is a complicated fabrication, I have a couple. My McGyver advice is to use either a treadmill motor or 110 lawn edger motor with pulleys and belt drive if you are set on a DIY motor. Tractor Supply Co. has pulleys for the belt drive, and the only other thing you need is a heavy duty intermittent button switch. I have grabbed a few curbside treadmill motors and the weighted wheel you remove and cut then reinstall the threaded pulley section. An edger motor is 750w about half the size of treadmill motor. Salvaged springs from a washing machine pull the motor mounted behind the seat, this keeps the belt tight. Those newer 3phase washing machine motors arent easy to mount. Hoverboards can be found free or cheap and are mini ebike motors, so a belt drive or sprocket drive setup could work with an ebike controller. Fabrication is the hardest part, but I suggest be careful at speed using a chain that may derail and cause a wreck. Full suspension frames are much safer and more comfortable for an ebike, potholes or a sudden tire burst at speed is no good. 20" rear DDhub motors are better in my opinion, for$200 they have a bit zippier feel and slight more torque on hills and wont burn up as easy. A 36v 10ah battery gets me about a 30 minute ride, an hour ride would be nice but a massive battery on a hardtail seems sketchy. I have the ebike addiction and 4 DIY builds now, and as a scavenger of frames and motors I have spent less than $800 for all of my bikes together. I bought my batteries used. Good luck!