Advise on ebike conversion for cargo bike

[bakfiets75]

Hi,

I want to convert my two wheeled cargo bike into an ebike. Specs: 20" front wheel, weight of bike 60 kilo's, cargo weight 30 kilo, rider weight 100 kilo, ebike conversion kit approx 10 kilo. Max required speed 25 km/h.
For flexibility and option to use on another bike I'm planning to operate it on a 48V 15Ah LifePO4 battery pack. rear wheel has gears in it and for ease of install I prefer to install motor in front wheel.

Most use will be in town so a bit of starting off and braking. Not designed for max speed. cruising speed 20 km/h. Not much hills here.

I did a bit of research and I came down at a few options from cellmann paul: 500 Watt direct drive or the Mac10T kit in a 20" Alex DM24 rim, with a 9 fet 3077 controller.

My questions: regarding bike weight, durability of the motor and (probably lower?) noise I would prefer the direct drive. When looking at efficiency, light weight, more efficient, and lighter to operate when not powered the geared MAC is probably the best option.

Because of the experts available here probably with both types, I hope to get some input of what you would choose based on these specs (can provide more when some "data" is not clear). Especially the noise of the engine, when operating at approx 20 km/h is an important factor for me.

thanks in advance!

 

[wesnewell]

Please go to the User Control Panel, select Profile, and then enter your city, state/province, and country into the Location field (country minimum) and save it. This will help people help you. Example: Wylie, TX, USA. Without knowing what country you are in it's hard to make any recommendations. Thank you.

 

[bakfiets75]

Hi, just updated it. I live in the Netherlands. No steep hills, mainly flat or a bit slight up from time to time.

 

[wesnewell]

Hard to say without seeing the bike. Normally don't recommend front motor for regular bikes but if the cargo bed in in the middle of bike it may be ok. Any 500w motor in a 20" wheel should supply plenty of power.

 

[bakfiets75]

Cargo/kids are more at the front/middle of the bike. This is the bike:

it's a steel frame, rollerbrakes front and rear, planning to replace the front brakes with a v-brake because of placing the front motor and also because I'm not very pleased with lack of brake power of the current roller brakes ...I'm planning to put the battery pack and controller in the cargo area under the seating area. Just found out, when looking for a picture, that the bike is also imported by J.C Lind Bike Co in Chigaco

 

[Drunkskunk]

Welcome to the forum. Good looking bike

The MAC would be my personal first choice.
But having said that, the silence of a direct drive is hard to pass up. That doesn't mean the MAC is loud. Infact it's a rather quiet motor, but it does have gears, and they do produce sound. The MXUS on the other hand produces about as much noise as a celing fan, except an occasional growl when under load. The weight penalty would be minimal when considering you're at 200kg total, and they are more efficent when runing at constant speed.

Both the MAC and the 500watt direct drive(MXUS) paul/cell_man/E3Mev sells are good choices. I don't think there is a "best" here, just one that fits your taste better.

 

[Samd]

I dump a kilowatt into an Ezee V2 on my wife's cargobike. I removed the rear 7 speed and selected a nice rolling cadence. The hub has enough torque to get the bike rolling with three kids from stop. A Mac/Ezee/BPM is much the same nowadays at 1 to 2 kW, but the ezee does have a better warranty if you blow a clutch or gears. That doesn't happen much anymore. I also used the Ezee in this instance because an expert wheel builder made it on a quality rim. The chinese BPM's I usually buy from greenbikekit would not be made very nice and we are talkign heavy and precious cargo.

The 7 speed rear hub has resale value to offset the cost. I agonised over running a dual front conversion but I can admit now it was pointless. A single speed rear is fine.

A geared hub will allow you to reverse, I think that is important in a bakfiets.

Ira did a nice direct drive conversion though.
http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=48226&p=710374&hilit=bakfiets#p710374

 

[bakfiets75]

Thanks for your responses.

I will be ordering a dd kit for the cargo bike, not sure about the gears will hold with 200+ kilo, have heard good stories about both motors. If this is a success, I will probably do a conversion for a 'normal' bike. Will keep you posted when conversion is done, probably in 1 or 2 months.

 

[holli2000]

Hi bakfiets75, have you made any progress on the build so far ? I am looking into a similar conversion. I have a short bakfiets from "De Fietsfabriek" want to add a motor. I live near you, only on the other side of the german border.

 

[bakfiets75]

Products arrived two days ago. Only modified front fork will arrive later on, had been sent to weld brake mounting stuff on it. Motor is a 500 watt direct drive from em3ev. Battery is 48v 15ah pack with 5 amp charger. Will update The post with a picture of The boxes that came in

 

[bakfiets75]

AH Krefeld is not far away. What kind of front brakes do you have? What conversion are you thinking about? Front/rear? What do you have in your rear wheel, regarding brakes and gears? I might have been easier of with a standard conversion kit, however this setup will probably give me more pleasure riding the bike. There are also kits with 350 watt geared hub motors with rollerbrakes on them and standard 36v li ion batteries. Future will tell what's best

 

[holli2000]

I have a Magura HS11 hydraulic brake for the cantilever brackets that are already on the fork. I have to wait for a tapper to arrive, as the screw thread is too rusty to mount it. I bought the bike of marktplaats.nl, it is used and has been standing around for quite a while.

I am thinking about a front wheel conversion, possibly with a cute100, or any kind of standard 250W motor that has windings for more torque than high speed. Sadly 250W is the legal limit in Germany . The rear wheel has a SRAM p5 cargo gear hub with backpedaling. This too is a bit rusty, so I might exchange it for a Nexus 7 or similar in future.

Where are you getting the brake caliper welded ? How much is the cost of doing that ?

 

[bakfiets75]

ah great. was also thinking of magura's... first tried with a traditional brake that's mounted on the center of the fork, however the reach of the breaks was not long enough to reach the rim. Welding is done by a dutch bike builder called m-gineering (.nl for the website). will cost me probably 40-50 euro. Could probably done cheaper by someone local, however wanted to have it good without compromises and quality work. Some time later I saw some forks with the brackets on them, but still not sure if it would fit my bike (threath length and diameter...) Should also be a steel fork because of the weight of the bike and sure with the hub motor in it. 250-350 is also limit in holland, and speed limit 25 I believe. Don't expect any problems as I'm not going to race with the cargo bike.

regarding torque/high speed... You will probably need a higher speed version because normally these motors will be mounted in a 28" rim. Mounting the same motor in a 20" rim will give you a lower speed. Check this site for a good calculator that will give you an indication and you can play with voltages of your battery pack, rim sizes, motors, etc. That's also the reason why I choose for 48 volts, it will increase rpm.

if you have your motor in place, you might also forget about the gear replacement as it not that necessary anymore.

please refer to this german site for more info, also on the cute100. I chose for the direct drive because I didn't want the noise of a geared motor. But can't compare it yet to anything else. There are a bunch of standard ebike conversion kit resellers I've found in netherlands and germany. Em3ev provided me with a 20" Alex DM24 (extra wide) rim, with the hub motor in place. That also was something I wanted: a new rim with the motor in place so I don't have to bother with spokes etc.

My dutch reseller sent me the wrong rim, so it will be next week before I can restart the project. Also need fork to come in and some other cable routing stuff to get it all hooked up.

the thing I (probably) regret is that I don't have a peddle sensor. I have thumb throttle. Just found that out and as far as I know that's not possible on that kit.. Will need to inform on that.
When I manage to get it al up and running, you're welcome to have a look if you want, it's about a 40 minute drive.

 

[Chalo]

Sadly 250W is the legal limit in Germany .

That's what "250W" stickers are for. I doubt anyone would ever question it if you're on a cargo bike and you keep your speed low.

 

[cwah]

For a cargo bike, I'd say the best in term of durability, efficiency, silence and brake ability is a dual direct drive. Get 2 HT crystalyte into it and you have your beast.

The only issue will be the friction created by 2 DD if you pedal :lol:

 

[Chalo]

In this case, I think a front wheel motor is the ticket.

First of all, since it's a long john, there will always be weight on the front wheel. Wheelies are not on the menu.

Second, it's a cargo bike so it needs strong wheels. Might as well leave the rear wheel as a normal bike wheel for better strength, and make the most of a symmetrical front wheel for the hub motor.

Third, the bike has drum brakes and thus will need a different brake on whichever wheel gets the motor. That's a better bet for the front wheel where (on a long john) the braking requirement is lower. Just a long reach dual pivot caliper brake on the fork should do it, as long as the bike has adequate rear braking.

Fourth, the front wheel is much smaller in diameter than the rear, making it easier to meet the stated performance criterion of decent thrust at low speed.

Fifth, the bike is not set up for derailleurs, so there would be some amount of retrofitting involved to recover some gear range after swapping a hub motor for the internally geared hub. Best to avoid that, I think.

 

[Samd]

If you are riding around town with stop/start intersections I'd forget the DD hubs - too much amperage to get it rolling. Went out on mine yesterday with the Ezee rear at 600W, great fun with the kids. Never needed to or went over 18kph.

I ride a q100 torque daily but if you are limited to 250W (or thereabouts) I'd not use them on bakfietsen. Choose a larger diameter motor from the MAC/BPM/Ezee family and get the extra torque for the low power level. I took the rear multispeed off mine and just run single speed. It's all you need.

 

[holli2000]

That's what "250W" stickers are for.

I am not worried about any normal routine checks and unless I were banging down the street at 40 kph overtaking a police car in my bakfiets I doubt anybody would notice. I would however be worried in case of an accident involving a 3rd party. That would lead to inquiries and further checks and this is where things can get very nasty and expensive.