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

[rider95]

This is your first E bike keep it simple use a geared hub motor mac 10 the mid drives are fairly new sounds great but let other people use them first get the bugs worked out , EMV3 will sell a complete mac hub motor ,controller ,CA, battery just about as cheap as any one and its all plug n play . The battery and were it will fit on your bike is just as important as the kit its self don't buy more battery then you need instead buy a fast charger with your battery . A mac kit with a 10ah bottle battery would get you about 18 mi and give you a very clean look.

 

[wineboyrider]

I'm just concerned 11Ah won't be enough but to be honest I've got no idea, if anyone can give an estimation that s accurate that would be good. Like I said in my first post I'm looking to go about 15-20 miles maximum with some pretty good sized hills and grass to get over and I'm looking at a 1000w or so motor, most likely the bbs02 and I weigh 10 stone/ 64kg

Depends on how much you pedal and how hard you ride? Just like gasoline in an ice engine the more stops and accelerating you do the more fuel you use? 11 ah if you used a mild assist option could get you 15 miles? If you are full throttling it then probably only 11 miles???? I'd say 11ah is too little for the 15-20 miles?

 

[dogman dan]

For speeds of up to 25 mph, 1 mile = 3/4 ah of 48v is a good rule of thumb. Call it about 14 miles range from 11 ah.

Much better range can be had, by riding just a tad slower, such as 18 mph. But for the most reliable 20 mile range at full speed, 48v 15 ah is ideal.

Those numbers are for street. On single track trails, I tend to get more like 1 ah per mile, even at much slower speeds. I tend to pedal a lot less in dirt, so you may do better. On a badass trail, I tend to have my hands full just standing the pedals and hanging on, and there is much gas-brake, gas-brake, over and over.

 

[nutnspecial]

I realize the bht middirect drive is different than hubs or reg middrives, but I'm seeing almost 2mi per ah w/ 5kw draw regularly, and I'm really not pedalling anywhere near what it normally takes to go hardly anywhere. Maybe it's just that I only need to blip the throttle in spd2 (75%) for 25mph, and sustain 20ish with peddling on the flat. I need to know how to properly test this thing I guess.

Are middrives more efficient than mac or dd hubs, and where does a fw'ing bht stand?

 

[TriggerGee]

With mid drives I'm limited to the bbs02 it seems because it's the least obvious and cheapest, I can't afford the other kits really. What are the problems with them? These niggles you speak of? Speed wise I cycle with my dogs so most of the time I'm doing between 5 and 10 mph and only occasionally going faster than that just to see them run full speed but they can't keep it up for long so I suppose my main concern for battery life is the hills and single track which consists of most of my riding.
My main gripe with the rear hub motors is I'd have to loose my 9 speed cassette and buy a 7 speed freewheel? I don't even know if that will fit on my bike so from what I understand my peddling without the motor would be affected. I'm also a bit lost as to which rear hub I'd go for if I did. What's geared and gearless? Are they heavier than the mid drives (1000w) and how bad is the balance shift due to the weight in the back wheel?

 

[nutnspecial]

These are good questions I hope you get more answers for.

I've only ever seen in person or ridden the bike I've built. Def different than hub or middrive.
For what you want a geared or middrive would be best. Middrive prob best for weight and selectable power.

geared is the same as direct except the motor is geared down x5 inside the hub. so for the same speed the geared is running 5x faster, staying closer to it's most efficient rpm at lower speed. The trade off is they don't handle as much power and highspeed, but you don't need to worry about that!

Someone did mention a hub that accepts cassettes I think, and would assume if it's advertised for 135mm d/o, a 8,9,10spd cassette will fit. But honestly my 2cents now is on middrive. Most control and best weight for what you want. I didn't price alot of them and didn't realize they could be less money too.

Handling weight is better with middrive, but a mac or cheap dd wouldn't be that much worse if you're not a demanding mtn biker.

I am mainly not speaking from any real world firsthand experience, so I hope someone corrects me if I'm full of sht.

If not enough middriver's are answering, find some builds and ask some questions. That's what I did, and it helps alot. It's mainly chance to get the best responses on your own thread imo.

 

[TriggerGee]

Thanks, I better start trawling through and try to find some relevant to what I need. I suppose one of my main issues is I've never ridden an e-bike other than my dads mobility power trike which was basically a 350w hub motor on a bmx style front end attached to a manual wheelchair, great fun and did 12mph on flat but was useless on hills. For this reason I don't really know how much power I need to get me up a steep hill at fairly low speed like 7mph also if it can cope with a few miles of grass that would be useful

 

[d8veh]

There are now hub-motors with cassette splines so you can fit whatever gears you want.

With a hub-motor, you have to choose one with the correct speed and power.

 

[nutnspecial]

I think even a 250w middrive will handle the low speeds and still give alot of assistance in the high gears.
Riding it without pedalling will give at least a normal biking experience, as 250w thru the gears is way more than even an olympian can exert continuously.

I don't think mobility units can compare at all?

Yep, asking some questions direct to people that are using the potential kits is paramount, as was finding video for me. Make sure you try the google search option too, it does better in some cases.

 

[TriggerGee]

I agree most mobility vehicles are pants but but this one pictured above really is closer to an e-bike than a scooter, I've done 40mph down a hill on it! Still I find its 350w motor useless for any kind of incline. It's torque I'm after really not power, the vehicle pictured below (also my dads) is called a Tramper. It runs off a 24v 73Ah gel type battery and produces just over 1000w....what I don't understand is although it only travels at 8mph maximum it will literally go up anything, the steepest hills with tall grass and can pull a car! It's torque is epic. I've knoticed when going up the steepest hills it momentarily pulls over 100 amps but most hills it uses 20-40 amps. If I could achieve anything like the trampers hill climbing on my bike I'd be very happy!

 

[nutnspecial]

Wow, all that power geared for only 8mph means it can almost go strait up. I've never seen anything like that.

30/40 amp running thru a serial middrive might be the limit on a bike, but that would possibly be the closest easily achievable system imo.
Compare it with a hub running double current, and the middrive will probably still out perform at low speed because of the low gearing possible.

 

[docnjoj]

64 kilos is pretty light. Some of us (like myself) are big (100 kilos just for me) so this helps you right away. I will throw another choice in (as if you need it) but a Xiongda 2 speed motor doubles your gear range on the rear. Simple to install and very good customer service if something breaks. It is a light weight motor (3.x kilos) and pretty strong, especially for a lighter person such as yourself. I am using one on my trike which weighs about 150 kilos with me and tools on it, but I don't do off road. Just another choice Low gear with 44 volts nominal will pull you up 10% and not overheat. It get s me up 5% grades but I do have to pedal. Finally not very expensive 250-300 USD delivered for the whole kit.
otherDoc

 

[TriggerGee]

Looking at the write up for the Xionda its claimed that a mid drive still should out perform the Xionda on steep hills, which is what I need it for. I live in Bristol, UK which is a very hilly city with hills of 30% gradient in places and the estate I cycle in is 450 feet above sea level and I live 30 feet above sea level so I climb 420 feet in around 500 meters or so.....this is why torque is vital and speed isn't. My dogs are happy running at 7mph so for hill climbs that is the fastest I will be going. Does anyone know if the bafang bbs02 can handle 30% hills? If not what will?

 

[dogman dan]

Steep hills! Bafang for that, but you will still need a very large cog on the back wheel to gear down to 5-7 mph. Lugging it up that hill in too high a gear is a problem, and the mid drive means you get their choice of front chainring. For your needs, likely too big.

If you could somehow combine the bafang with a 20" rear wheel including some very large rear gears, that would help a ton. That of course, means a new bike most likely.

 

[Lurkin]

Or get an adapter for the front and use a different sized front chainring to chain the ratios. On Em3ev you can purchase the kit without the standard chainring if you choose this route.

I have been riding a BBS01 250w for the last ~3,000kms. Battery is a 36v 16.5Ah frame pack. All of the above from Em3ev. I get about 70 - 80km per charge, but that's mostly on the flat. Paul from Em3ev has endeavored to answer many of my questions etc. I paid more, but have had no issues and appreciate his ongoing support. I will be buying from him again in the future.

Definitely slows down for hills... I think you are on the right track re BBS02.

You should probably now review what tools you need to install it, i.e. ring spanner, Hollowtech crank tool, crank remover, cable ties vs what you actually have. Buying these will also add to the cost... maybe there's someone in your area who could help out? otherwise buying them online is pretty inexpensive.

 

[TriggerGee]

Wow that's some impressive range! I wish I had less hills around here and could get away with a 250w. Tool wise I do quite a bit of motorbike mechanics and general mucking about so probably have what I need somewhere if not I'll buy off line I expect. Em3ev looks like a really good site and I think it's the one I'll go for so its great to here you have had good experiences with Paul. Perhaps going with a smaller sprocket on the front and an extra large on on the back could be good as long as it doesn't effect my range to much. I still don't understand how the Tramper I pictured is so powerful and only runs off 24v? I thought you need 48v volts for real power so I clearly don't understand something properly.....

The picture of the trike I posted above I also plan to 'pimp' up.. I'm going to weld up a wider frame for the rear and plan on fitting 2x 500w hub motors at the rear to replace the one 250w in the front wheel as it suffers on the hills with wheel spinning. What would I need to connect two hub motors to one throttle? Two controllers wired to one throttle I guess.

 

[d8veh]

If you're in the UK, it will be relatively expensive to buy from Em3ev. Fortunately, we have our own reputable suppliers like Eclipse:

http://www.eclipsebikes.com/motor-kits-bafang-8fun-drive-motor-c-73_130.html

And Woosh

http://www.wooshbikes.co.uk/?cdkit

 

[TriggerGee]

Thank you! Saved me a fortune there. I've noticed this forum has many very knowledgable people on it but many are in the U.S. So some UK support is much appreciated, as is the advise from the U.S. Before I put anyone off helping lol it's just sites to order from and regulations are more relevant to me if they've been used by UK users.
I'm very close to ordering the bbs02, most likely with a small ish 11Ah 48v frame battery to start with. I'm still concerned that the motor won't be big enough but haven't seen a better option yet really.

 

[motomech]

Dave (D8veh) is involved with Ebikes all the way from visiting factories in China/ prototype testing to us neophytes and he has built and tested just about every type.
His advice is golden.

 

[minimal]

Hi!

I got myself an mtb fitted with an bbs002 from china and it has conquered every hill I have tried (and I live in an area with lots of big hills!) so I am sure it will fit your needs.
I´m actually so satisfied that I have ordered an kit and 2 bottle batteries (from uk, since it is cheaper for me than from china where I have to pay custom duties and tax) to fit on a bike for my wife (also ordered from uk since bikes are a lot cheaper than here).

 

[TriggerGee]

Nice to hear some good feedback for the bbs02, I don't doubt if it's pushed too hard it will burn out but hopefully taking it steady on the motor will make it last.
Looking on the eclipse web site they recommend using the headway cells for the 750w or above not the lithium ion 18650 cells.....I was thinking a frame battery would do but if I follow their advise I'd be better off with the more expensive headway cells. Looking at their packs they look really easy to build at home? Just screw together 16 cells with one of their bms boards and the jobs a good'n basically, way easier than soldering 50+ 18650's together.

Another thing I saw on eclipse was the cyclone motors, looking at the 1260w and the 1680w kits the claimed 40amp continuous and 100amp limit is as far as I know pretty damn good! They look quite bulky and on videos they sound very noisy. Does anyone know if they are any good? The bafang bbs02 say it has a 25amp limit, is that right? That seems quite low.

 

[d8veh]

The Headway batteries that 3clipse sell are very big and heavy. IMHO the 18650 09 bottle batteries are a much better solution. They're OK up to 20A at 48v. Do you need any more power than that? The lighter weight allows you to keep your bike like a bicycle. It'll have enough torque to get you up any hill with a geared motor like BPM or Q128.

 

[Ykick]

Not only large and heavy but Headway builds aren't quite as simple as it may seem.

Critical torque specifications for the screw terminals or possibly rupture the cans. I messed with them a bit - started with 10qty several years ago and now down to 4 which still work as a 12Vdc power brick. Every time I lift it up I'm grateful I never built a bike pack using those cells.

 

[JoyRiddin]

Trigger,

I have a bbs-02 750W in a 29er Fuji frame. 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. You will not be able to add the manual brakes levers with the built in switches that come with the kit and the after market in line will not work either. I would also look in to a frame bag. If you are going to single track a battery rack for the seat post will have to be severely reinforced, especially with a hard tail. I broke two already. EM3ev sells a great frame bag and there are others but I have not tried them.

As for speed there are three selectable power levels. Each of these has different top speeds. Using the peddelec 1=approx. 9mph / 2=approx. 13mph / 3=approx. 17mph. Using the throttle 1=approx. 15mph / 2=approx. 24mph /3=approx. 33mph.

Just FYI for the above referenced - I am 6'3" and weigh 250lbs and I am using a Calibike 48V 15ah battery. Using an in line power meter, I see a significant voltage drop at 1200W, (Yes this kit will draw 1200W peak), almost 4volts. Must less drop with my HK Lipos.

Rich

 

[TriggerGee]

To be honest I'm still fairly unsure of how much power I need I don't think I need to travel as far as some do, 15 miles is an absolute maximum but the cycle does involve so pretty steep hills which I'll be tackling at around 5-7mph maximum.
After looking more closely at the headway cells they do look to big and heavy for my needs so I'm back to the 18650 9 pack in 48v OR what about the A123 48v pack from eclipse? Granted it's only 4.4Ah but as d8veh points out I may not need as much as I thought. Even though it's heavier by 400g or so it does have a higher voltage of 51v as appose to the 18650's 48v I've got no idea how far that pack would take me though...

Thankfully for the motor and battery I'm very light, only 64kg/140lbs so with the bike probably a combined weight of 180lbs I guess that makes things easier and more efficient. As for the brakes, is it possible to use a twist grip throttle? I think I'd have enough control that way to shut the motor off. Being a motorcyclist I'm very used to that kind of throttle.

Your help so fps has been great, there is so much to learn and most posts are still baffling me