Converting a cargo tricycle (bakfiets)

[bakfiets]

Hello,

I'm just starting my first ever ebike project, having become a parent lately I need some form of family transportation. Because cars are smelly and expensive I've bought a brand new cargo tricycle, like the one shown in the picture, which will be delivered the 16th of June, I intend to electrify this thing, allowing me a top speed of at least 15mph and hopefully a 40 mile range on a $3000 budget, (of which I've already spent half on the bike and accessories and still need a couple of things like a heavy chain to lock it, lights, stereo, chopper style handlebars, tan seat and grips, whitewall tires and some paint to make the box black). Total weight of the bike with motor and batteries will be approximately 250lbs (130 for the bike, 80 for batteries and 40 for the motor, controller etc.). Weight carrying driver and maximum load is about 650lbs, typical weight in day to day use will be about 450-500lbs., driver inluded. I know this is a lot (!!!) of weight, so I hope I'll get away with no pedaling with a single motor setup on the rear wheel. The last couple of days I've been studying the technical aspects of ebikes to find something within my budget and so far I've come up with the following setup:

6x 12v AGM Deep Cell batteries configured as 72v (20ah, 40A continuous, peak current 90A)
Crystalyte HT3525 Rear hub motor
72v40a sensorless controller (Crystalyte or LYEN if he has a working one on offer)

The rear of the bike will need some adjustments as the dropout width is only 115mm and the bike comes with hub gears and a drum brake. Luckily it's a steel frame so hopefully I'll be able to bend it out 10mm on each side. For the gears I'm not sure yet if I'll install a single speed cog or a 7 speed freewheel, as pedaling will be very heavy wether there's gears on the bike or not. If I fit he 7-speed I'll also have to fit a new shifter, derailer, and a special eye for it on the axle as the bike frame doean't have a mount point for it. I've found an adapter to fit a disc brake caliper on the horizontal dropouts, originally intended for those cruiser/chopper bikes, I hope I can use it together with the torque arms. I want to remove the rack on the back to give it a bit of a cruiser look, so the batteries will have to go either in or under the box.

Is this ever going to work with a decent range or this thing just too heavy for a single motor setup??? Can anyone tell me how well the sensorless LYEN controller works on the new crystalyte hubs as I hear mixed reoprts, I need it to be able to take off from standstill (the sensorless crystalyte can do this I believe), I have no problem with shudders at 32mph as I can't imagine going any faster than 20-25mph with this bike. Is 72 volts the way to go here or should I upgrade some wires, try to find a higher amp controller (or beef one up) and run a lower voltage, I don't care about top speed, even 15mph would be fine, I just need loads of thrust.

 

[dogman dan]

Pretty ambitious build! Here's what I would be trying myself.

Start by adding part of another steel frame to the bike, welding onto the bottom of the frame. This would get you a disk brake mount, derailur hanger, and dropouts lower than before. Spread to width of course.

Then you can have a 5 speed at least, and good rear brakes. The reason for the lower axle mounting point is so you can run a 2812 9 continent motor, which you can buy very low priced from Methods in the for sale new section. It comes in a 20" wheel, and when run on 72v it will be a climbing beast, even with a low amp controller. A good climber will also be a good low speed motor for cargo hauling. With any motor, a 20 inch wheel will get you better performance in the speed range you want.

Alternatively, weld a disk mount to the rear frame, spread it, and use the low speed windng motor of your choice in a 26" rim. You can put a single speed freewheel on the motor. the 2812 at 72v would go about 25 mph on a lighter bike, but loaded up, you might have about the right speed. Methods also sells a 2810 motor, that goes about 20 mph on 48v.

 

[bakfiets]

Actually I was hoping not having to resort to cut a brand new bike to pieces, also I'm afraid that if I fit a 20" wheel instead of 26" (increasing torque by 25%) the back will look like a bmx, killing the already not so flashy looks of this thing as it is. The 9C motor sounds interesting, it has a lower top speed at 72v than the HT crystalyte hubs (25 vs 30mph) so I guess it has more torque, which of course doesn't have te be so, but as the HT motors are a 9C style design as well I assume they do. The thing I liked most about the HT hubs is that I can get them from a Belgian vendor (crystalyte europe, I know you guys don't have the greatest experience with their customer service), being Dutch myself that means I can get them "from around the corner" , which has my preference over having them shipped from overseas. If there's a motor out there that's definately better for my purpose than the Crystalyte, I'll ofcourse have to reconsider having it shipped.

 

[GCinDC]

What's your terrain like? I'm sure Dogman's right about that motor.

I've got a 9x7 9C and it's not fond of low speeds pulling heavy loads - It growls at low speed - and I ride up some steep hills pulling myself (170) + bike (70) + trailer w/ 2 kids (110) and sometimes 5 kids...

Also, a 40 mile range is substantial. My first reaction is that 72V is overkill if you want to go 15mph. with hub motors, there's a direct correlation between voltage and speed. So my first thought is to go 36V and then double your capacity, from 20Ah to 40Ah.

I wonder about putting one (or two?) motors in the front wheels...

 

[TylerDurden]

40 miles is a long distance. Fortunately, things are pretty flat around there.

20Ah of Pb is worth about 10Ah usable, yielding ~720Wh.

If thrust is most important, perhaps consider a mid-drive and internally-geared hub.

 

[nieles]

yesterday i ordered a hs3540 from cyrstalyte europe.. i will let you know how long it took, and other observations

where are you located? i am in zwolle

good luck with the project!

 

[bakfiets]

Terrain around here is completely flat, apart from the occasional bridge, I've been thinking about double front motors but figured that it would be overly complicated and expensive for a first build. I know 40 miles is along stretch, and it's not a real requirement like it would be when using it to go to work, I'd be more than happy with 25 miles as well. I wanted to configure my batteries in 72v because that would give me a theoretical top speed of 30mph with the Crystalyte HT hub, which would be pretty close to the 20-25mph I'm looking for. Altough 15mph would be the fastest I'd be travelling 99% of the time,and the bare minimum speed the bike should be able to do, it's nice to have a little extra straight line speed available, if I can get more thrust while retaining reasonable topspeed on another motor with 36v, I'll do that. The specs of the batteries I've chosen say that even when discharged 70%, they should still last a couple of hundred cycles, so for the few times I do have to travel more than 20 miles (very rarely) I guess that would give me about 1000watts of available power. I've looked in to geared motors briefly but written them off because I expect them to noisy, less reliable and generally lower powered (they're still singlespeed, so more low end means less high end and viceversa) than DD. For appearance I don't want to go with a chained solution.

Definately looking into more torquey motors for my build,perhaps even the geared ones.

Hi Nieles I'm in Almere, let me know how you fare with clyte europe!

 

[Rassy]

Dogman's advice on the motor is good.

Here's my two cents. Start with the slowest wind DD you can find in a 26" wheel. The 9C 5X12 from methods would be good.

Start with a BMX type single speed freewheel for simplicity. Add gears later if you need them.

If you have good front brakes, you may not even need a rear brake, so save that as a future project also, if needed.

Whatever you decide to do, good luck with the project.

Edit: Battery. Just start with 48 volts. Should be plenty. And don't get too many, because you'll want to go to a better chemistry soon.

 

[bakfiets]

Thanks for all the advice, looking in to the low rev 9C's now, 6x10 has roughly the same speed as the Crystalyte HT 3525, 5x12 seems interesting and will give me 15mph on 48v in a 26" rim. But it's in a 20" wheel so I'd have put a 26" rim around it myself and the sales thread is closed anyway so I don't know where else to get a 5x12. Aren't the crystalytes more powerful than the 9c's? Wouldn't that compensate for the difference in winding between the 3525 and the 5x12 9C? Or is power all about how many watts you throw at it and less about the motor?

 

[Rassy]

I can't get too technical, but yes, it is the watts that count. Most of the hub motors can do the same thing with the same watts. But, issues such as the motor over heating, the wires over heating, the controller over heating, etc. depend on things like the speed you ride, the maximum speed the motor wants to run at, etc. So if you get a single speed motor that is happy at 30MPH, it will be lugging and overheating at 10MPH, etc. This is why, after trying several different hub motors, I ended up running the motor through the IGH. For me this works great, since I have a 15% hill to get back to my house (actually 20% in my driveway). If I want to go faster up the hill I can just shift up a few gears, shorten the life of my battery by drawing more amps, and start heating things up by lugging the motor down.

Even though you are on flat ground, you will still want to ride fairly slowly when carrying a large load. That is the point where I think you should concentrate your build effort. Make your other bike, everybody does more than one ebike, a faster regular bike to buzz around on when the cargo trike isn't required.

 

[wesnewell]

Try this. It should get you 30+mph if you need it.
http://www.yescomusa.com/product.php?productid=729&page=1
You might want to remove or change the freewheel.
No way I'd use sla batteries on it. For 40 mile range, you'd probably need 80ah of lead, over 200lbs. With lithium, 40ah should get you as much range at a faction of the size and weight. I'd use lipo, but a 40ah ping or similar is just a little bigger and heavier at 40-50lbs.

 

[dogman dan]

Always good if we know your location when you start asking. I doubt Methys wants to ship outside of the US with his stuff very much. I got fooled when you used stupid yank mph.

In any case, you are on the right track with the torque version. It won't have more torque, but it will feel like it since it's a slower winding.

 

[GCinDC]

Make your other bike, everybody does more than one ebike, a faster regular bike to buzz around on when the cargo trike isn't required.

Agree!

Also, motors & controllers are relatively cheap. Having a battery that can go on different rides is great!

 

[bakfiets]

Sorry for using stupid yank mph, I was under the assumption that most people reading this board think in mph and lbs, so that's the units I used

I've been looking around for a 5x12 9c, nowhere to be found, except maybe from methods, but indeed he doesn't like to send outside the US. And even then, the wheel would be $220 I believe, plus shipping, and if I'm unlucky customs charges as well, not even mentioning having to get it fitted in a 26" wheel. I'm afraid that would turn out horribly expensive in the end.

If I got my facts right, the Clyte HT motor should have a winding of 9x7, so I hope that will do, but how come the speed of the clyte 9x7 is similar at a given voltage to a 6x10 9c? I just hope it won't overheat on low speed. What do you think handling would be like if I fitted a front hub motor in one (and later maybe both) of the 20" wheels??

Still not sure on controllers and what voltage to run. 48v would give me a theoretical top speed of about 33 km/h, what would be plenty, but to maximize power I'd like to be able give the motor as many watts my weight of batteries can deliver sustained, which is close to 3kw. Running 72v, that would mean a 40 amp controller could utilize all available energy, which is easily available from crystalyte and is supposed to work well with the sensorless wheel, also from a standing start. 72v will give me a theoretical top speed of 50km/h, too fast, but as long as it gives me maximum thrust, and no further problems, I'll just drive it slower. On 48v I'd have to run a 60 amp controller to get the same wattage as on 72v, and the right top speed, but will this give me more torque as well?? There are no 48v 60 amp controllers from Crystalyte so I'd have to beef one up (Is this difficult? I'm no hero with a soldering iron, but if it just involves laying a coat of solder on something I guess I'll manage), or buy a modified Infineon controller with sensorless board, but there are mixed reports on how well the sensorless LYEN controllers are working with the HT's

I've been looking at some specs of electric scooters, and found out that most have a hub motor in a 10" wheel, not sure if it's DD but I think so. The weight of those is similar to my bike, speeds are 25-45km/h, and they have about 2-4kw, the same range I'm aiming at, so that gives me good hope my setup will work.

I really like all the high tech lithium batteries, but being on a tight budget, and because weight and handling are less of an issue on this bike than on a regular one, lead is the way to go for now, max 35-40kg.

 

[Rassy]

What do you think handling would be like if I fitted a front hub motor in one (and later maybe both) of the 20" wheels??

I'm not very enthusiastic about having just one front wheel powered. However, if you do try it I would like to hear how it works out.

However, I've used both two and three identical motors and controllers working off of one throttle, but never on the front of a tadpole type trike. Several have been close to trying it, but as far as I know none have reported doing it. Personally, I think it would work great, since the electric motors working together with no mechanical tie don't really care if one has to spin a little faster, (or slower), during a turn.

My findings when using two hub motors on a two wheel pusher trailer really worked great. The motors seemed to compliment each other such that the performance was better than just a linear 2X as good. Also, unless you are always accelerating extra hard, your battery usage with two motors is not much different than having just one motor. This is probably because the watts required to move a certain weight a certain speed is the same whether one or two motors is used, and since the motors aren't working as hard they aren't wasting as many watts creating heat.

Too bad you are so far away, or I would loan or give you a couple of WE BD36's already laced in 20" wheels just to try this out.

 

[bakfiets]

I don't think I want to be a guinea pig to be first one to try to drive a single front wheel, so I guess that won't be an option. After looking around I just can't find a slower motor than the HT, while also being able to handle a lot of power. So I guess I'll just start with the HT, and if that's not enough, maybe I'll add two geared front motors when budget allows me to.

After running some numbers on the simulator I found out that 72v40a problably would give me better torque than 48v60a, but only slightly, with the tradeoff of less efficiency on low speeds, meaning more heat I suppose. So I'll go with 48v, I'll try to get me one of those 12fet sensorless lyen controllers and have the fets upgraded, or leave the 4310's in and run it on the absolute limit which I think will be around 55-60 amps.

Batteries will be four either 28ah or 32ah Deep Cycle AGM batteries, with a 2C rating.

The bike arrives in 10 days, I hope to have most of my parts by then as well, I'll let you know how it all works out.

Thanks for helping me get started!

 

[dnmun]

why not try adding an extracycle frame at the back and using rassy's design that resembles a stokemonkey knockoff. longer wheelbase too and then you can use the xtracyclke shelf and bags in back or make your own.

still have no clue where you are. it is flat in louisiana too. alexandria, la. is @80 feet and it goes flat to the gulf. i have 3 times that much in my back yard in colorado.

 

[mr.electric]

I set up a kid hauler and use it daily to pull a kid trailer.
http://www.youtube.com/watch?v=PDUO5G_QRZk&sns=em
My two kids love it and many people in the neighborhood comment on it. I know my neighbors a little better and have explored the area now that im out of the car a bit. I use a stock 9c motor with 22 amp infineon controller ( standard issue ebikekit.com stuff)and a 48v 10 ah lifepo4 battery with built in balancer. Similar to a ping pack but more expensive
http://www.hi-powercycles.com/product.sc?productId=12
The bike was originally 48v 10 ah lead acid powered but the weight and range limitations sucked. In fact the finished bike sat for a year while I did other things. Then I switched to lithium. I spent more on the battery than the motor kit. The lighter lithium pack completed the bike and started off the daily use I described. I'm not sure which winding 9c I have but I bought one of the 9c front wheels that was sold in a blowout sale here a few years ago. It goes about 25 mph but accelerates very slowly. It grunts going up hills but has never failed from day 1. I live in san Francisco and torture that motor. I only pedal with moderate force on the steeper hills. It will climb a moderate grade at a good clip with no pedaling while pulling trailer, kids and back packs.
I also helped a friend set up his ht35 + lyen 12 fet extreme controller. To compare the ht35 has too much power and speed for a kid hauler. It goes 30 or so ( speeds are all estimates) but gets up to speed in less than one city block while my lower powered set up takes 1 and 1/2 blocks to hit terminal velocity. This results in an inherently safer kid hauler. On short blocks and congested areas I'm going slower , out on the open road I'm going faster.
I would recommend the ht motor you are looking at , a lower amp controller or a lyen turned down via USB cable to the
25 amp range and a lithium pack. FYI the lyen sensorless 12 fet extreme controller and ht35 on my friend's bike have a sync issue at a certain rpm that has not been resolved and cause a jerky vibration at high speed. I will update if changing the current limit on the lyen controller resolve this annoying issue.

 

[bakfiets]

Well, it's not just going to be a kid hauler, more a haul everything you can fit in it bike, and for that I can't imagine there's such a thing as too much power. Besides, throttle controls power in the end, so it's all up to the driver. Having just looked in to the Ping batteries, 48V20ah is about three times the price of 48v30ah lead, but would make the bike a whopping 27kg lighter, making it 73 instead of 100kg. Having more available energy in a Ping pack, plus the weight bonus, this makes Ping very tempting. So I'll just have to try to scrape some extra money together or postpone other mods I wanted to do on the bike to later this summer.

I heard about the issue on high speed before, at around 50-55 km/h on the HS, so I guess if the HT has the same problem, it will do so around 34km/h, which is (slightly) higher than my top speed will be.

Her's a pic I found of the bike running a crystalyte (4 series?) motor with the back rack removed and black painted box, much better looking already.

 

[mr.electric]

I agree that it is all controlled by the throttle. I also have a bmc 1000 with a 50 amp controller on a dual suspension mnt bike. It is just nice to be able to go full throttle almost all the time. Kind of like riding a 50cc scooter. riding with more power on a kid hauler is a bit of a different issue. I use my kid hauler for other errands too. The trailer carries penty of weight and bulk. I really have been happy using this vehicle around the neighborhood. I use my 10 ah lifepo4 battery for a few errands before I even bother charging. I have thought about doing an electric rickshaw next. http://www.sunshinebicycle.in/indian-rickshaw.htm
This way I could haul kids and wife. I have a 2010 Honda Fit but it is always a pain to park and I do enjoy drinking beer during ebike rest stops... Not a very good option in the car.
In respect to lead vs lithium. You could buy one 10ah pack and add another later when money is available. It is more reliable to have a redundant battery set up anyways. I only build lead packs when I get free lead cells. Spending money on lead batts seems like a waste. To compare lead and lithium effective range I half the lead rating to compare to lithium rating. Lead 10 ah is really about 5ah. Lithium 10ah really gives you the 10ah. If you want cheap lithium you could build an rc pack but that would involve significant time and complexity.

 

[Mundo]

Here's another trike, very nice..... Nihola

http://www.nihola.com/products/family.html

 

[GCinDC]

Well, it's not just going to be a kid hauler, more a haul everything you can fit in it bike

sweet pic. dvd players on board for the kiddies? plush interior? lol.... but seriously, what sort of seating do you have in mind for them for 30 miles (or whatever)? that you can remove to haul mulch instead? got many bumps on that ride?

ping batts are great, as long as you're not drawing too much current.

 

[mr.electric]

Maybe just throw some pillows in there.
It is true that the ping batts will not work if you go with a big amperage controller. I think they are good to 3c. Which means 30 amps at 48v from a 10 ah pack ???? I could be wrong there. It seems that my lifepo4 pack can produce more like 70-80 amps since I use it on my BMC with a 50 amp controller and it has only cut out a couple of times in extreme circumstances like racing other Ebikes up hill.

 

[GCinDC]

It is true that the ping batts will not work if you go with a big amperage controller. I think they are good to 3c. Which means 30 amps at 48v from a 10 ah pack ????

just looked, and the 48V 10Ah v2.5 pack:

Rated Discharging Amperage: 10 Amps
Max Continuous Discharging Amperage: 20 Amps
Maximum Discharging Current: 40 Amps
Discharging Cut-off Protection: 30 Amps

i killed my ping inside of 6mo using a 45A controller... that said, with the proper 20A? controller, it should last for a long time and provide double the range.

 

[mr.electric]

I bought this one first
http://www.hi-powercycles.com/product.sc?productId=12
40 amps continuous 60 amps peak for 10 ahr
Unfortunately it costs twice as much as a ping !!!!
I see why everyone goes lipo my second pack is lipo
This one
http://www.ebikessf.com/50v10ah-lipo
50 amps continuous $200 less but it is not Lifepo4
I feel the lifepo4 is safer but I do not believe the cycle life claimed. I don't expect more than 500 cycles out of any battery. Any more than 500 and I would be happily surprised.