lavadisco

Hi,

I'd like to build up my first e-bike. I'd like to make one that's throttle-driven, not pedal assist, and can go 10 miles. I'm an electrical engineer so presumably I can save some money and build up something good? I already have a cruiser that I can convert. What kit or parts would you recommend?

rscamp

You just asked a question with a million-and-six possible answers.

Here are few suggestions.

1. Don't ask for a parts list first. First research ebike tech (motors, controllers, batteries) and what is available. Battery technology and maintenance are particularly important as batteries make or break a system. See 2. and 3.

2. Talk to Justin at ebikes.ca (Grin Tech) if you ever get the chance. He's an engineer who knows more about ebike technology than anyone else I know. His company can supply kits or components but with Justin that is almost secondary.

3. Join Endless Sphere. 'nuff said.

4. Then make your own informed choice based on what you've learned.

The first conversion is just a learning exercise so don't sweat that it might not be the ultimate solution. Unless of course you don't want to make it an ongoing hobby in which case you may as well just buy a good COTS conversion kit.

powell

Welcome to this sub forum.
I am Electrical Engineer also.
I own 3 ebikes, I commute 330 days /year at minimum including subzero winter and rain on ebikes, mostly E+ and TForce/20,509km as of this moment/.
I own 3 ebikes including legendary Tidal fORCE and E+ bikes.
Do you want reliable quality US-built ebike for regular commuting or rather occasional ride?
I understand as an engineer you want complete, weather-proof, energy efficient ride , not patched-up, rolling experiment ,low tech ride.
Read no farhter if you DON`T want hub motor , rather bottom bracket type.
I encourage you to read posts about E+ on this forum, visit web site.
NMH battery spoils E+ bike what is otherwise wonderfully efficient, high tech, rock solid bult ebike.
You want to build from components, well, bigger component - motor if you want
built-in-motor-electronics technology is simply not available to buy because they comes with ready kits like E+, BIONX.
You cannot buid motor yourself.
China-brands if you don`t get frustriated dealing with them as an engineer offer undersized wires/you don`t want to waste power/, external controllers, low efficeincy,everything exposed to weather BUT CHEAP.
I respect Justin from ebikes.ca and appreciate his customer service.
His Cycle Analist is excellent design.
However he faces hudge struggle to make it right on Chinese brand components. Struggle with rusting inside motors, undersized wires, falling of pole magnets, brittle plastic, wire isolation cut by sharp entry into motor.
QC in China facory unlike in USA is hit and miss thing or not there at all.
As I said you have to start with efficent, built with quality material like bearings, magnets motor, no matter what electronics you add to power it if you have crude mechanical design with shoddy magnets and bearings, etc. - you will not achive much.
everthing starts with motor which must be designed with extensive modeling in right equipped lab to get it efficient.
If you have a look at E+, NMH 30 cell battery of this bike completely ruin perfectly good , wonderful drive, efficient, built like tank and light with US quality materials.
/just imagine it can draw just above 1000W-1050W at sustained 45km/h and that's peek draw, usually 950W at that speed/ - it says a lot about efficiency of E+. 9 power levels are NOT gimmics, they are well designed. E+ is wondeful exercise machine which just love love to be pedalled.
Again it takes 5 hours to fully charge its Nickel battery including 1 hour balancing stage - that's radiculous. Tech mind tells you that it must be a way to power E+ on 3-party battery.
Shortly, I am looking for technical partner , electrical person ,engineer ,E+ owner to work on this.

lavadisco

Thanks for the replies, guys. I'm pretty sure I want to build my own battery pack from scratch (36V Li-Ion or Li-Po). I'd like to buy a COTS front wheel w/motor (750W?) and COTS controller. I can do all the wiring. I don't need anything fancy like a display. I'd also like the ability to convert the bike back to non-electric in 15 minutes or so.

I took a look at the E+ bike kit - I don't like having the battery pack in the front wheel, I'd rather have it on top of a rear rack. But otherwise it looked pretty nice. I will do some more research and talk to Justin at ebikes. Thanks for all the help.

rscamp

As an electrical engineer, surely you want to know your instantaneous energy per unit distance, MIN/MAX speed, current, voltage, set cut off voltage/max current and have a PI controller at your disposal for additional control options. You want a Cycle Analyst whether you know it now or not.

And why limit to 36V?

Are you familiar with battery management? Are you planning to balance on charge? How will you know when to stop using the motor without damaging the battery pack? Rather than dumb systems with no monitoring on the bike or during charge, build a system that you can measure battery performance (as with a CA and a charger that measures things like mAh in, internal impedance and maybe even has a computer interface so you can see the voltage profile and state of balance on charge). The CA was designed by an engineer (Justin). Nothing compares to it in capability. Check out the latest info on it at ebikes.ca. He is even working on a PWM I/F to work directly with R/C controllers...

Sangesf

I think the point of him saying he's an EE, is that he wants to go as cheaply as possible, since he wouldn't need a full blown altogether kit, because he can do the wiring himself.. And adding a CA will add $150 to the price tag..

The kits I sell and use are 36v 500w systems complete with everything you need except batteries...
And I'll tell you, the batteries from Ping (Lifepo4) are considered the best (albeit the priciest of the "duct tape vendors".
I buy my batteries from yxm on eBay and their 15ah lifepo4 is $300 and their 20ah (really 21Ah) lifepo4 is $389 (both prices are shipping included) and has worked beautifully for over a year with no problems whatsoever.
The 15ah batt should get you about 22+ miles at 20mph and the 20ah one will get you close to 40 miles at the same speed for only $89 more.

Just my .02

P.S. If anyone has any questions about my kits, just PM me.