Post accident...9yr later I want to finish an e-bike build

[CraigBannister]

Back in 2008 (ish) I bought a bunch of stuff to build a bike...then had an accident (I fell from a ladder) and could not finish stuff so the bike etc went to the shed.

My old member name was banmac

What I have, I bought from "Knuckles" on the forum but I don't think he's active any more.

Short story: Just want to use what I have to get a bike going.

Longer story: Could maybe upgrade some bits to today standards (if required), but I'd prefer to try existing stuff first

I have:
Bafang QSWXB (front hub motor, 100mm, 36v, 250w)
spare metal replacement gear (as back then peanut butter gears was an issue)
spare nylon/plastic gears
Infineon controller [up to 72 Volt – 45 Amp (w/ 12 – irfb4310 mosfets), with the transistor mod for variable VLC]
A bike, with the motor mounted in the front wheel
Throttle etc etc

I don't have batteries yet.

Questions:
Who on the forum still may have a Bafang QSWXB as their motor? (Voicecoils once did but he appears inactive)
Who on the forum has Infineon contoller experience? (Knuckles once did but he appears inactive)
Should I be buying a 48v battery pack? If so who would you talk to?

Any assistance on where to start will be gratefully received.

Cheers,
Craig

 

[skeetab5780]

Is your controller programmable? Do you know the low voltage cutoff point? If so it sounds like you just need to pick a battery and possibly mount some torque arms since its a front motor at high amps. Once you know the lvc you can decide on what voltage pack to buy. If its programmable its up to how fast you need to travel?

PS welcome back!

 

[dogman dan]

Sounds to me like your stuff is up to snuff, even today. But perhaps a bit mis matched.

Your controller is a bit high power for the motor, in my opinion. You might need those steel gears. I would say 48v 20 amps would be the max to ask from that motor. 1000w, and usually plenty for most riders needs. Easiest thing might be to just buy a new controller to better match the motor, or get a big motor to match the controller. Big means more money for the battery, so a 50 buck controller might be a better decision for now, than a 2-300 buck motor.

Or,, look into how to put a cycle analyst plug on your controller, and use the CA to adjust your amps limit.

Batteries have come a long way, so that choice will either be easy, or hard because now you have more than one choice of vendors. (2008 it was ping or hobby king)

Best way to do this fairly cheap, would be a modest controller and a 48v 10 ah battery. You'd have decent speed and power, but not so much you have to go big on the battery. 10-20 miles range, with 10 miles being fast as it goes, little pedaling.

 

[CraigBannister]

Thanks Skeetab & Dogman.

1) yes the controller is 'programmable' (see here....https://endless-sphere.com/forums/viewtopic.php?f=16&t=7361&hilit=Infineon+Controller+Technical), at least for different battery voltages. I have the transistor mod.

2) Also, I also have a CA and the controller has a CA direct connect plug so I suppose max current could be set.

Cheers,
Craig

 

[dustNbone]

Looks like your biggest decision is battery choice. Like Dan said, there are lots of options out there now, but you need to specify your desired range and at what speed you want to achieve that range.

Also. Torque arms.

 

[dogman dan]

Awesome! you are all set for running whatever voltage and amps you choose.

Most likely, you are already set in the controller for a wide range, like 36-72v. With the CA, you can easily set max amps and the low voltage cut off without having to get into controller programming.

Again, I would suggest 1000w as the max to expect that motor to handle, and last a long time. So using that as a guide, choose a 36v or 48v battery, depending on the top speed you want. Then set amps to 20-30 amps, so when you hit the throttle you see about 1000w or less max.

You might want to set amps even lower, if you choose a very small battery, such as 10 ah. It just depends on what you buy for a battery, how much amps it can handle and not get all hot. If your battery gets hot, beyond just pretty warm, turn down your amps on the CA.

Later on, you will be able to run a very high power motor with your current controller, and a new battery able to handle 45 amps continuous. But that motor you have will last better at sub 1000w. To make the original soft gears last, sub 500w.

250w is the legal limit where you live I think. So bear that in mind when you see a cop, and back off the speeds.

 

[CraigBannister]

Thank you dustNbone...I also have the torque arms. Found them in my bitsbox. Forgot I had them. Also, range requirement is minimal, only 7km each way ( I am 60yrs and not a current cyclist!) though there is some elevation change! (see the Google maps screen shot)

Thanks also dogman...I'll take your advice and keep below 1000w. I think I'll go for a 48v pack. Not that I'll need it for my commute...but who knows where it'll take me at the weekend!

Much appreciated. Now need to sort a battery source, so I'll do some reading of that chapter on the forum over the weekend.

Cheers,