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Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 17 2020 8:36pm
by hrc
I want to convert my commuter to and ebike. I live in Belgium so it doesn't get any flatter, so no gears should be needed, I commute 40k per day and it's dangerous to go faster than 40 km/hr in the bike paths.
The bike I want to convert is a Ghost Square Urban with Gates belt, this one https://www.ghost-bikes.com/en/bikes/la ... n-58-al-w/
- What would type of engine would you recommend? Rear hub or middle motor? (fork is to flimsy for front hub), 500W should be enough?
- Trustworthy store to buy motor/battery kit ? Would this kit work? https://em3ev.com/shop/bafang-36v-250-500w-bbs02-kit/
- Ideal battery to use?
- How could I avoid using a throttle and just use a torque sensor to control speed/power?
I just want to buy a kit that will later will fit my bike.
Thanks for your help and sorry for asking such a basic question.

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 17 2020 9:45pm
by E-HP
hrc wrote:
Jan 17 2020 8:36pm

The bike I want to convert is a Ghost Square Urban with Gates belt, this one https://www.ghost-bikes.com/en/bikes/la ... n-58-al-w/
Welcome to the forum!

A front hub (as opposed to the mid-drive from your link) may be your only option, unless you're willing to go through a somewhat complicated conversion, mainly due to the belt drive. I'd go with a geared front hub and size the battery based on your desired range.

https://www.ebikes.ca/tools/simulator.h ... wheel=700c

If you're going to pedal (the above assumes no pedaling), then you can go with a smaller battery. Looking at the bike, possibly a jumbo shark (with good cells, 17.5Ah) or something similar may fit.
https://www.ebikes.ca/tools/simulator.h ... wheel=700c

Plus, slowing down just a little bit can extend your range by a lot, too due to wind resistance.

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 17 2020 11:40pm
by Dauntless
Innto every parade some rain must fall. The durability of a motorized expensive carbon fiber bike pales in comparison to an under $100 Huffy steel frame from WalMart. If I wanted to maintain. A 40km\hr pace I'd seek bigget than 500w.

I know, governments all over the world want you to virtuously exhaust yourself on that trip with just a 250w motor thats all but no heelp whatsoever. Tell 'em to. . . .

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 18 2020 5:23pm
by hrc
E-HP wrote:
Jan 17 2020 9:45pm
hrc wrote:
Jan 17 2020 8:36pm

The bike I want to convert is a Ghost Square Urban with Gates belt, this one https://www.ghost-bikes.com/en/bikes/la ... n-58-al-w/
Welcome to the forum!

A front hub (as opposed to the mid-drive from your link) may be your only option, unless you're willing to go through a somewhat complicated conversion, mainly due to the belt drive. I'd go with a geared front hub and size the battery based on your desired range.

https://www.ebikes.ca/tools/simulator.h ... wheel=700c

If you're going to pedal (the above assumes no pedaling), then you can go with a smaller battery. Looking at the bike, possibly a jumbo shark (with good cells, 17.5Ah) or something similar may fit.
https://www.ebikes.ca/tools/simulator.h ... wheel=700c

Plus, slowing down just a little bit can extend your range by a lot, too due to wind resistance.
Thanks EH-P for your reply! After doing some research, yes you are right, the belt makes it really difficult to use a mid drive or a rear hub motor, a front hub engine seems like the easier option. BUT the fork of this bike I wanted to use is aluminium and flimsy so I would need to change the fork, so I have change my plans:
I changed my mind and now i will convert my single speed bike to and ebike.
My plan is now to install/buy a 36V 350W rear hub motor with a 36V11.6Ah battery. Would this kit be not a waste of money? https://www.greenbikekit.com/electric-b ... ttery.html
I plan also to include a torque sensor so I dont need to use the throttle so riding the bike will still feels like a normal bike.
If above kit makes no sense, what other brand/type of rear hub engine & store would you recomment? Or a different approach?
Thanks again!!

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 18 2020 5:59pm
by E-HP
I think you're headed in the right direction, but just to manage expectations, there's only a limited number of controllers that are compatible with torque sensing pedal assist sensors. If you want to go that direction, you may want to think about a cycle analyst 3, that can accept a torque sensor, and provide the right signal to most controllers. However, the CA3 has several PAS options that might meet your needs without the cost of a torque sensor (which is fortunate, since the CA3 costs just a little less than a torque sensing PAS).

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 18 2020 6:36pm
by markz
I am glad you didnt say you had to be X wattage because of legislation.
Because otherwise I'd go on a rant about giving the middle finger to "The Man" but I digress.

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 18 2020 6:58pm
by hrc
E-HP wrote:
Jan 18 2020 5:59pm
I think you're headed in the right direction, but just to manage expectations, there's only a limited number of controllers that are compatible with torque sensing pedal assist sensors. If you want to go that direction, you may want to think about a cycle analyst 3, that can accept a torque sensor, and provide the right signal to most controllers. However, the CA3 has several PAS options that might meet your needs without the cost of a torque sensor (which is fortunate, since the CA3 costs just a little less than a torque sensing PAS).
:thumb: thanks for the tip

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 18 2020 11:28pm
by markz
Might be able to pick up a CA here on ES for sale thread, always worth a look.

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 19 2020 12:21am
by amberwolf
there is also the kt kun teng kunteng open source firmware by casainho / stancecoke / etc that will handle a number of torque and cadence pas sensors as well as throttle, etc. requires a bit of diy as you must reprogram the controller with the firmware and setup the parameters to do what you are after.

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 19 2020 6:38am
by dogman dan
Really nice bike,, but it leads me to one of my most repeated pieces of advice. Don't ruin your favorite bike with a motor. That will neatly solve the problems you would have motorizing that one.

Here's the deal, with the motor to help, you don't need to worry about weight. Adding up to 25 pounds of motor and battery for a typical direct drive system, your bike may not be so light anyway.

Lighter systems exist of course, the geared hub motors, or the mid drive. Pick a mid drive, if you would like to haul heavy trailers. Otherwise, with no hills, all you need is a simple and reliable smaller power geared motor. 350w rated motor, with perhaps 500w power. A small, affordable, rear hub motor. It will be plenty of power and speed, yet much lighter and affordable than bigger 48v motor systems.

The bike can be very cheap, and still be a very very good commuter. A typical cheapo steel beach cruiser with 7 speed rear gears will work fine. Mostly, you just want a bike with fenders and a chain guard, and no front derailleur. BTW, you won't shift much ever again, so it can be junk, and work fine for years. shifter quality simply does not matter with an e bike.

But a better pick, would be a decent quality commuter type bike, or cruiser, with the same features. Preferably disk brakes, 7 speed derailleur, fenders, and possibly a rear rack that is welded to the frame. You don't need skinny tires, again, the weight and drag of a big 26' cruiser wheel is no problem, you got motor help now.

But if you insist on using that bike, then go with a 36v, lighter geared type front hub. But you will have to put a steel fork on the bike. It should be fairly cheap and easy to swap forks. But seriously, a very affordable steel beach cruiser would work for not much more money.

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 19 2020 8:22am
by AngryBob
Mid-drive in flat country?

Mid-drive on a belt-drive bike?

Hub motor on a carbon-fiber bike?

25 miles at 25 mph on 36v, 11AH?

None are impossible, all have been done, but there are several good reasons to call these less than optimum for a first build. You should be familiar with ALL these issues before you proceed any further.

How far do you go now, on pedal alone, and how much pedaling do you desire to do twice a day, 5 days a week? Do you really think you will maintain that pace when motor is available? Some folks will, but the vast majority will not.

Can you charge at work? Not, is there an outlet available, but can you do this with a homemade ebike connected to the building owned by the person who signs your paycheck? That person may be more concerned with protecting a major investment and their life's work than saving the environment and making things convenient for you.

How smooth are your roads? How much do you weigh? Can you arrive a tad late sometimes?

Will you ride in the rain, or is that optional? Can you go a bit slower, or is 25 mph mandatory?

Do you need to lift the bike up steps or stairs? Do you have a secure parking location? Do you need an easily-removable battery?

There is what you WANT, there is what you NEED, and there is what you HAVE TO HAVE. Make a list, and be prepared to compromise.

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 19 2020 10:27am
by MikeSSS
The replies so far have provided the answers. I'll add a bit, from my limited experience.

40 km/hr is fast on a bike, their geometry is designed for slower speeds because that is where most ride them.

40 km is very doable, a battery that can easily do 80 km will last longer than one that can do only 50 km. I'm referring to charging only to 4.0 volts per cell and never discharging to below about 40% of battery capacity. For a given road speed, 48V will pull fewer amps than 36V, fewer amps should provide longer battery life. Another thing, as the months go by battery energy capacity will deteriorate. This reduced capacity battery still needs to power your ride using substantially less than 100% of the now reduced capacity.

Like the wise man said, you won't shift much on an ebike on flat ground. It is nice to be able to vary the cadence occasionally, 7 speeds will work great for this.

A suspension seatpost and/or fatter, lower pressure tires will put less stress on the spine.

I changed from a normal bike to a crank slightly forward, flat foot when stopped bike. Gearing was 3 x 6, now it's only 7 speed. Yes, I'm slower now, but don't fall over when stopped. Riding seems more stable, especially on tight corners. Slower is probably because my top gear is lower than before. The "new" bike is a Jamis Hudson, it's a lot like an Electra Townie.

I've done probably 4000 km on front hub bikes, they work just fine. I mount the battery and controller on the rear rack. A direct drive hub will give less acceleration from a start, compared to a geared hub. Less is more controllable at very low speeds. A big bag on the rear rack can hold the battery, chain and some groceries or other stuff too.

A throttle allows you to vary the percentage of pedal effort you provide. The body goes through ups and downs in the effort that feels good, the throttle allows a constant road speed even with varying pedal effort. My thumb throttle gave me a lot of sharp pain during the first two or three years of using it. A twist throttle is more natural, besides it's the same as your scooter and motorcycle. Crank RPM pedal assist has always worked badly for me, high risk for negative reward. Some torque sensor pedal assists have been better, others have not. It is very hard not to pedal on a throttle only ebike, we are bike riders pedaling is what we do.

Hope this helps, keep us up to date on what you decide on and how it works out.

Best wishes,

Mike S

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 20 2020 9:52am
by hrc
Hi all. Thanks for the great advise and your time to reply. I have become a bit less uneducated on ebikes builds.
After all you have said + some "common sense" i will:
  • Buy a 2008 26" MTB to use as a donor bike, with decent disc breaks and geometry // 150-200 EUR delivered
  • Get a "good enough" rear hub geared kit of 250-350 watt[/url][/url] // 200-250 EUR delivered
  • Get a 36 or 42V bike with 12.5 or 15 AH (or 500-600 Wh) // 250-300 EUR delivered
With that configuration I plan to have an ebike where I can ride at 30-35 km/hr on flats while adding some human watts with my own legs (Almost all is flat in Belgium)
Because this will my first build I will avoid the Cycle Analyst / Torque sensor path for now ... maybe that will be a fun upgrade or something to try on new builds. (So for now good old throttle)
I will source the motor/kit/battery from some chinese companies that have EU stock, so almost free shipping so I can keep the cost on 500-600 EUR (plus donor bike).
Possible purchases: Hope I dont break anything! Thanks!

Re: Advise on how to convert to my commuter to and ebike. Mid or rear hub? 500w? Battery?

Posted: Jan 20 2020 11:36am
by 2old
My first kit five years ago was front hub, 36V, with a 15 amp controller (still in use by my daughter). The top speed I could attain (throttle-only) was 20 mph and on flat terrain it was difficult to go faster than about 22 mph with vigorous (for me) pedaling. If you still want to go 24 mph, be careful what 36V kit you obtain.