UNI/BUSH EBIKE HELP

J

Jazzman56

100 mW
Joined
Sep 6, 2014
Messages
38
Location
Australia, NSW
Hi Everyone,

I'm looking into building an ebike in order to get around UNI easier and aid in my recovery ( I have a knee problem and struggle to walk any reasonable distance) + to beat around the bush :D . I have a reasonable level of understanding in electronics and can solder easily (as-well as basic debugging tools CRO/Funct.Generator/DMM etc)

I need some suggestions on components/construction methods etc.

Budget: about $1500-->2000 ish..
Power: 1.5kw + (I need a reasonable amount of torque to climb several hills in a daily commute + getting up hills at uni)
-->Preferably Rear wheel hub drive (unless something is better suited)
Range: 25KM+ (Will be a very long day if i need to push it home...)

Needs to be reliable and able to handle light rain.
I'm Considering getting a Vector Frame when launched on kickstarter.

Regards,
Jazzman5
 
How steep a hill you need to get up will matter, so find out the grades. Most bike hubmotors will get up 10%, but pedaling to help above 8% is usually recommended.

A "500w" gear motor should do the trick nicely, when run at 1200w. 48v 22 amps controller. I've been testing one out in the last week, and I'm very impressed with how it scampers up hills as good as a very slow wind DD motor, yet still has a nice 28 mph top speed. Noisy above 25 mph though.

The other great climber would be the bafang bottom bracket motor. This one runs through the bikes gears, so you can put it in the lowest gear and slowly grind up nearly anything with on of those.
 
$1500-$2000 can build you a VERY nice ebike. You could spend less than that and still get a great bike.

I second Dogman's question about hill requirement. That will help us all recommend something more specific.

I've always been partial to gearless (direct drive) hubmotors due to their long lifespan and whisper quiet performance. 9C's are my favorite, but there are many options. For strong hill climbing without worrying about overheating, a motor like a 9C 8x8 or 6x10 would be good for you. An 8x8 should be easily picked up from ebikes.ca, or maybe somewhere in australia but I'm somewhat less familiar with the suppliers down under. 6x10's are harder to find. You could get a front 6x10 from ebikekit.com's etrike kit, though I've been recommending them less ever since their CEO has been out for my blood… (and you'd need a good strong torque arm for a front motor like that one)

A 48V battery with a 30A controller will get you your 1500 watts, and both are very common. A 48V 10AH battery should get you 25 km easily, though I'd actually bump up the capacity of the battery to 15 or 20AH if you can afford the $$ and space on your bike. That will both keep the battery healthier and increase your range even further.

Most ebikes are fine in light rain as long as you've done a few basic things like not have wires running straight down into the controller or motor (search for "drip loop") and put some silicone on the back ends of your connectors. I always make sure to bring my ebike into a garage or something similar so it can drip dry after riding in the rain.

Give us some more info and we'll point you in the right direction. Also, you'd be surprised how well an ebay kit can work if you get it from the right place. People have had good luck with kits like this one: http://www.ebay.com/itm/291119531800?var=590270751128&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
 
Welcome to the forum. Two things we'll need to know are what part of the earth you're currently on. We're international, but sometimes it matters when recommending something. And how steep those hills are. My idea of steep may be different from Dogman's and MLT34's since I'm in a different part of the world from each of them. "Steep" is subjective.

Steeper hills need a motor built for climbing, and it's usually slower than a motor that will handle shallower hills.

The good news is you can build a good bike for that budget. 25km range at 35kph usually takes a 36v 15ah or 48v 10ah battery, so nothing too extraordinary there.
 
Calling it now, 'straya.
Bush, I'd says full suspension
Hills, I'd say mid drive.
25km, 48 10Ah if you can charge after arriving
 
Hi Guys,

Thanks for your input. As t3sla said i'm from Australia :D
The gradient of majority of the hills is around 10%...

Also Can someone point me in the right direction with a screw on freewheel for a rear 9C /crystaylte hub motor?

Is the quality of a Crystalyte motor vs a 9C worth an extra $220 ?
(http://e-mtb.com.au/index.php?main_page=index&cPath=65_66)

If so where is the best/cheapest place i can get a Crystalyte motor (2.5kw) ? shipped too or within Aus.

Regards
Jazzman56
 
Any screw on freewheel will work with a 9c or clyte motor that has a screw on thread for it.

Figured it was AU or NZ from the use of bush. But that only means you came from there, not you are there now. Updating your profile will let us know where you come from in every future post. Just which continent will be plenty.

Great suggestion of a slower wind 9c such as the 6x10. Trouble is, where the hell you find one nowdays. Looking at the link you gave us,,,, bingo there they are. http://e-mtb.com.au/index.php?main_page=product_info&cPath=65_66&products_id=246

That's a great motor for single track trails and dirt roads. Great for cargo bikes that weigh a lot. It's SLOW, though, so on 48v it will only go about 30 kph.

This motor will run really great on 72v, with a 20 or 30 amps controller. Better still with a 40 amps, but by 40 amps it can melt the motor pretty easy in summer.

This extreme slow motor won't be needed, if your hills are less than 10%. 8x8 is a good choice if you want 40 kph out of 48v.

Re the rain, it's a matter of covering the plugs, putting some sealant on the controller, and covering the throttle if parked in the rain. Riding in the rain, you can cover the crack in the throttle with your palm.
 
Whoa back a bit.
Suspension or hardtail.
Critical.
 
Thankyou Dogman,
The 8x8 is looking good for the 10 extra km/h..
Any Controller Brands to keep a more keen eye out for ?

I'm assuming that li-po's are the way to go :D and that hobbyking generally has pretty good deals.
What is the sort of stock standard Lipo pack used and BMS (and charger ?? i'm assuming it will balance the cells on board) ?

Samd,
Most likely a hard tail, tend to be cheaper and more easily available. (thats unless i can't find a dual susp. one for a good price).

Thanks for everyone's suggestions :D
 
Yep, the 8x8 would be a good way to go if you have many hills and want off road, or a 7x9 if you want to lug more weight up hills. On the other hand, he 9x7 is the usual default motor for the street.

However, their prices are Nuts! If you need a slow motor, this appears to be one of the few sources that stocks them, but the prices need a straight jacket and a little padded room someplace quiet.

If you want a direct drive hub, get one of these motors, but get the other parts elsewhere. If you want a geared hub, try here: EM3ev.com, specifically something like this: EM3ev.com/Mac Kit.

The 10T motor with a 12FET controller and your choice of options. Also add to that a Cycle Analyst and a programming cable and you have the basis for a very good system.

As for the batteries, HK Lipo are the ebike equivalent of running Nitro methane. They aren't cheaper by the time you get all the monitoring and charging equipment you need. They aren't even close to safe, and they don't give you any performance advantage unless you're pushing the bounds of ebike performance. Run Lipo on a race bike, use a good high performance Li-ion for a commuter/fun bike. And as it happens, the best source of those at the moment is the same company I linked. EM3ev.com/Battery Lots of choices in size in shape, so pick one that fits the frame you choose.
 
How does a BAFANG BBS02 (750w) middrive kit compare to a 2KW 9c or Crystalyte direct drive hub motor?
Can the Bafang Kit sustain 1.5kw for any length of time ?

How much power/torque to ride up stairs --> hence looking at BAFANG middrive ?? :D

How does a Hardtail VS Dual Suspension change the performance characteristics?

I'm well aware of (most) dangers of lipo's XD
EDIT --- EMVe3.com shipping battery to aus is $100

What is the best cheapest way to make / build / buy a battery pack ? 48v around 15ah


Regards,
Jazzman56
 
Jazzman56 said:
How does a BAFANG BBS02 (750w) middrive kit compare to a 2KW 9c or Crystalyte direct drive hub motor?
Can the Bafang Kit sustain 1.5kw for any length of time ?

How much power/torque to ride up stairs --> hence looking at BAFANG middrive ?? :D

How does a Hardtail VS Dual Suspension change the performance characteristics?

I'm well aware of (most) dangers of lipo's XD
EDIT --- EMVe3.com shipping battery to aus is $100

What is the best cheapest way to make / build / buy a battery pack ? 48v around 15ah


Regards,
Jazzman56
Click to expand...

2kw is pushing the limits of what an unmodified 9C can do. For bursts it's fine, but constant 2kw will melt it without some modifications.

I haven't played around with the BBS02 so I can't speak to it's 1.5 kw performance. I assume you intend to use an exterior controller? The stock controller maxes out at about 1kw.

Stairclimbing is definitely mid drive territory. Switch to your lowest gear. Also, museum steps, not staircases.

Rear suspension will remove some of the shock loading on the motor, spreading out the loading curve a bit. The bigger difference will be in how it affects the ride though. If you have room on the frame for all your batteries, and can afford it, go with rear suspension. Don't cheap out though. Cheap rear suspension is worse than a cheap hard tail. Same for forks.

Cheapest way to build the pack you're talking about is RC Lipo, after ensuring you understand the safety precautions. If you want to avoid RC lipo, you could buy 18650 cells or some pouches on aliexpress and solder your own pack to a BMS. It would be fairly labor intensive but would be a fun project and give you a real sense of accomplishment when you're done. Until you remember that twelve year old chinese girls do the same thing 20 times a day… :?

Generally speaking I am big supporter of as much DIY on your bike as possible. When you build your own battery, you know exactly what goes into it and you understand how it works. Makes repairs much easier in the future (and much less likely if you do it right the first time).
 
8x8 with 72v will be a blast, but you might just want to try 48v first. Leaping in at 72v is not for everybody. It depends on your native mechanical and intellectual skills.

The 8x8 on 48v will be plenty fast to have the cops looking at you.

For strictly bush, I still would say go the slow motor. Bear in mind, the "slow" motor goes 48 kph with 72v. Just a wee bit over your 250w rule for street.

The complete 9c kit price isn't that bad, not in AU dollars. Starting with one of those, more like 1000w might be a good thing. The less powerful controller will let you spend less on batteries.

Make the decision on what more powerful controller to buy later. But don't go over 30 amps with a 9c motor, unless your ride length will be less than 8 miles.
 
To go up a ramp at the same grade as a flight of stairs, say, 45 degrees, 100% grade, you would need to produce thrust at least equal to half your combined body and bike weight. So if you weigh 175 and your bike weighs 75, then your motor would have to produce 125 pounds of thrust. That would take around 150 foot pounds of torque, depending on wheel size. and that's not max torque for the motor, which is made at 0 rpm, that's torque made at whatever acceptable speed you want to climb at, which is much less than the stall torque.
Stairs take even more power as the grade up each step is much greater than the average, but the actual power needed depends so much on the wheel size and the step's shape that calculating it is pointless without knowing the specific bike and flight of stairs.

Don't expect that kind of power from a bike under 6-7000watts.


The BBs02 is good to around 1k power. its still too new for anyone to guess how it will hold up compared to hub motor. You could be the one who tests it to it's limits. That bit of Pioneering ain't been done yet.

Hard tail VS soft is mostly a matter of complexity. Its damn hard to mount a battery on a full suspension bike, and mounting the battery anyplace except the center of the frame almost always comes with a big trade off in handling and performance. You can successfully convert a hard tail into an ebike on a lunch break, and never need to mess with it again. Getting a full suspension right can take years, and usually needs to have custom parts made
 
I'm looking for a similar solution for my brother, but he is on a smaller budget I think. Currently looking at some stuff from overseas, as an alternative to the cheap ebay kits he was looking at.

It seems one can get a cute Q-11 at 1kw with controller from here for cheap http://www.bmsbattery.com/ebike-kit...-driving-hub-motor-e-bike-conversion-kit.html
And batteries with bms/charger http://www.bmsbattery.com/battery-pack/685-bottle-ebike-battery.html

Would this setup suit you? alternatively you can get a bbs02 or other bb kit, they will give more usable power, less plug 'n' play though.

Is this site/deal/setup any good or is one best spending more straight up?
 
The trick with those bottle batteries is the small amount of current they dish up. They are good city commuters. But no bush bike. A q100 will generate 50 newton meters max, and the bottle battery will serve up about 14 amps.

If anyone is interested for a similar amount I do sell locally BPM motors/wheels capable of a lot of torque with matching controller and throttle, and HK lipo makes a nice match. I bring them in to match the custom frames in my link. You can build a bike like this for quite a bit less than 2k.
PM if you need details...

You can have your thread back now!
 
That motor/controller would be rough on that battery. I have the same motor but I run it on the KU93 controller instead. @48v it's still about 1200W. Also, if he can afford it then this battery is the same style but with better quality cells that will withstand that motor better. http://www.bmsbattery.com/battery-pack/684-bottle-ebike-battery.html
 
Hi Guys,

I'm looking at the 72v 20ah battery from http://www.lifepo4.in/72v20ah-.html is this site credible ?
How does the 10t mac motor compare to a (8*8 ish) 9c ?

Realistically how much power (watts) can something like this http://www.giant-bicycles.com/en-au/bikes/model/talon.27.5.5/14926/66447/ hold up to ?

If i can find a DH i'm definitely looking at build something similar to Adam's Guerilla ebike ( http://www.electricbike.com/guerrilla/)
Although i have no idea how he got a Hub Motor to work in middrive...

Samd I'll PM you soon :D

Regards,
Jazzman56
 
You will find a 72v 20 ah lifepo4 like that impossible to carry. Well, not impossible, but the bike will ride like you have a case of beer in each pannier. It's gigantic, and will weigh 35-40 pounds.

It's a turd, unless you plant to tow a trailer to carry it forget it.

That bike is quite adequate, but don't go over 3000w with it. It will still handle sketchy, hit a nice manhole cover at 60-70 kph, and it will buck the back wheel into the air. Can you handle a 60 kph stoppie?

Much better imo, with a hardtail, to keep to 48v, and go no more than 50 kph.

The 10t is a nice motor, I'm road testing a version of one right now. Not as rugged as a direct drive, but capable of handling 1000w continuous just fine. Many run them on 1500w.

RPM wise, the 10t Mac is comparable to a 9x7 9 continent. But the 10T has a LOT better performance on a steep hill. I think a 10t mac and 48v 30 amps controller is all you need for a first build.

Later on of course, we all want more. :twisted: But something like the Guerrilla is a really advanced fabrication build. That's not "got a DH bike" so much as "built my own" DH.
 
That's why I suggested the Bafang. It's a Uni build.
Pretty much the same performance as the mac for less than half the landed cost. :roll:

Jazz man, got your PM. Will get through today's swarm of infants (birthday party at ours) and then drop you a line.
 
Hi Guys,

I may have found a Dual Suspension mountain bike frame.. :D
Although there don't seem to be terribly much room between the down-tubes to fit a battery pack, what is the best way to get around this ?

What is the best way to charge a (72v) 20S or (48v) 14s XP lipo/lipo4 battery pack..
Where is the best place to get BMS pcbs ?

Regards,
Jazzman56
 
Hi Guys,

The frame fell through :/ getting a hardtail :p ( Maybe Norco Storm 7.1)

Where is the best place to get HEADWAY cells, Shipped or within Aus (using a Bafang bbs02 (750w) middrive) ?
http://www.aliexpress.com/item/48V-10AH-38120S-HEADWAY-LiFePO4-Battery-Pack-DIY-kit-for-ebike/1884564115.html

Regards,
Jazzman56
 
Mid drive bbs?
You sounded like you were up for some fun!
 
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