Advice on full e-bike build for someone new to the field

[Ykick]

Being a motorcyclist I'm very used to that kind of throttle.

Me too, many many many miles/years and I thought full twist would be the way. Thing is, our moto experience is with something that uses a gearbox and has a neutral. So when pushing it with the engine running and you inadvertently twist a full grip throttle the worst that happens is the engine revs. Do that same exercise with a powerful eBike armed and ready to go, what do you think's gonna happen?

Personally, I found the thumb throttle to be my favorite but just try them all and decide for yourself. You'll drive yourself nuts with all of the "opinions" about this topic.

 

[Supertux1]

I have both the MAC10T '500W' and BBS02 '750W' on different bikes.
They're both closer to 1500W depending on how much you want to gamble with heat.
The math doesn't quite add up on the BBS02 '750W' version since it's controller is rated at 48V 25A... (1200W) but I easily push 58V to it.

They are both powered by the 18650-22P cell pack in a 14s9p configuration, the triangle one sold by cell_man.

That pack was approximately 18.5Ah two years ago, after the first year it was about 15-16Ah, but now estimate it is now about 13.5Ah with hard riding (25A draw most of the time...) I ride it mostly every day in the spring, summer and fall and it has had over a thousand charge cycles from half to full. No cell failures, just showing its age, still charges up to about 57.4 volts or so. (Rode gently to LVC cutoff last week, CA said 13.5Ah, put back in 13Ah as measured on a WattsUpMeter through the charging plugs.)

It takes me 6.5Ah to go 10 miles to work with the BBS02 and that is mostly WOT throttle and changing gears a lot to be efficient up and down hills and mostly no pedaling (only around cops and crowds.) Top speed 40mph downhill, about 30-35mph on the flats on a 29'er. I have a lot of stop signs, intersections and obstacles (other cyclists and cars) etc... so city miles. I estimate another year with this pack, maybe more. By that time I'm hoping there will be some awesome new 18650 cell out there to replace it.

Whichever power source you choose, remember that all of these 18650 type batteries lose capacity over time. If you build/buy a small pack that you use %100 of its capacity every day, you're going to have to replace it more often. It might be worth it to just have bought a bigger more expensive pack to begin with to provide yourself with some overhead for whatever your needs are.

I always use the brake cut off circuit. Eventually someone you know is going to want to try your bike and this is something you want, especially if you also have some sort of PAS sensor which is on by default in the BBS02. When I loan my bikes to people, I disconnect the throttle and tell them to just pedal....

 

[TriggerGee]

I've just been reading through the pond post on the bbs02 and I'm starting to see the mass off differing opinions on it. I also see your point ykick about the bike running off, that could be irritating and I'll just have to cross that bridge when It comes lol. I've got no idea what to expect but On the whole many people seem to have good experiences with it and I'll only know if it's got enough power once I try it.

I'm not going to be using it every day by any means as its only for taking the dogs out really and the don't get a ten mile run every day. I typically cycle along a path that is fairly level and not too rough for about five miles, stopping often as the dogs mess around. Then I have a section on Tarmac that is a sustained hill of maybe 15% for around 2 miles which later has a short 300 meter hill at maybe 25% max and finally I cycle through a country estate and through woodland, all down hill to get me home again so really the motor only has a few miles of hard work to do and the battery only needs to do it a couple times a week.

 

[Lurkin]

I think a better question is - is there anyone near you who has a bbs02? Going a riding one will clear up most of the speculation on here.

One main problem I see is going to come from your brakes. When you are negotiating any off road terrain you will need motor cut offs. I noticed that earlier in you stated that you have hydro brakes.

Use a reed switch or hall sensor as a cut off. Well documented on here how to do this.

Use 18650 cells. Yes, PITA to make, which is why you buy the pack welded by someone else. Once its made, its plug and play.

 

[TriggerGee]

I'm assuming there is something I can do to wire my brakes to the controller but I'm not sure what a reed switch or hall sensor is right now lol, I'm sure I'll know soon enough. I'd love to have a go on one but I very much doubt I'd find someone close even though I live in a city of 500,000 people...in the UK we are limited to a ridicules 250w so unless they are willing to break the law on this one as I am most likely to come across 250w kits. Local shops won't even talk to me about anything above 250w it's pathetic. Can anyone direct me to a thread on building an 18650 pack with a bms? I've got 50+ or more used 18650's which hold 1,500mAh - 2,200mAh so it seems silly not to build a pack, it may only be 6-8Ah in 48v 13s4p but that's ok for £50 on used laptop batteries and a £20 bms right

 

[Lurkin]

Yes. That's exactly what I'm telling you. There are cheaper ways to do it - but these are nice and work well -

http://em3ev.com/store/index.php?route=product/product&path=41&product_id=196

Yes. There is a search button at the top...

But to get you started - http://endless-sphere.com/forums/viewtopic.php?f=14&t=69683&p=1051325&hilit=+build+18650+pack#p1051325

Maybe start a thread to see if theres anyone in your area willing to meet up with a bbs02?