Heavy cargo hauler project

[Cargo_Tom]

Greetings folks.

I first want to tip my hat to the community for all the useful knowledge sharing available to new recruits like myself. I'm looking at using an electrified cargo bike as a car alternative for commuting, shopping and kid hauling. As I have recently gone back to college for an engineering degree (Green energy tech) I fully intend to immerse myself in the theory behind ebikes and understand as much as possible. I realize that many folks here are speed freaks, and I intend to join that club for subsequent projects. But for now, you might say my ebike focus lies in the realm of tractor pulling. I'd be grateful if you took a gander at the lists below and helped me plug any loopholes before I start my spending spree.

Needs

• Pedal assisted transport of cargo uphill up to 10% incline.
• Daily commute, mostly flat terrain with a single incline.
• Needed total range 15mi/25 km daily @ 650 lbs/300 kg.
• Mostly EU legal (pedelec*, top speed at about 25 kph).

Wants

• Increase battery capacity above bare minimum to preserve cell life. (reducing C-rate and DOD levels)
• Budget of $2000 give or take.
• Front wheel system preferred, if viable (smaller front wheel will provide better torque).

Theoretical point of departure
Playing with Justin's simulator has yielded this as a promising start:

Starting build list

• 1964 SCO Longjohn All-steel cargo bike, 85lbs, 16” front rim (20" wheel), 19" rear rim (23" wheel)
• Custom road case, weatherproofed. For components and cargo.
• BMC V2 Trq motor hub. (any high torque DD alternatives out there? )
• Monarch 16” moped rim, 12ga spokes, single cross pattern.
• 35-40A controller. (overbuilt to prevent headache)
• Upgrade brakes. Currently only has a coaster brake!
• Add disk brake to front wheel. Weld attachment points to front fork or replace fork with a disk friendly version.
• Add cantilever brake to rear wheel if possible. (moped rims)
• Cycle analyst + Cycle analogger.
• Embedded PV array + charger down the road. (ineffective, but fun)

Battery pack:

• Either 48V 20Ah 4S1P LiFePO4. battery pack http://www.ev-power.eu/docs/GWL-LFP-Product-LP12V20AHB.pdf
• Or 48V 40Ah 4S1P LiFeYPO4. http://www.ev-power.eu/docs/GWL-LFP-Product-Spec-LP12V.pdf
• Other suggestions welcome.

Pedelec system

• *Override button would be nice.
• Feather sensitive would help, magnet rearrangement might be in order.
• Half-grip throttle.

Styling:

• Weld new bed. Ladder pattern to support road case superstructure. Cargo box acts as front fender.

Soo, Whaddaya think?

 

[neptronix]

( i retract my original recommendation after learning what kind of power is needed in reality to do this.. )

 

[Ricky_nz]

[*]Mostly EU legal (pedelec*, top speed at about 25 kph).[/list]

25Kph my (300W elation/cyclone setup with some extra volts) mid drive bike is really hard to keep below 25Kph in the lowest gear, it is necessary to pulse/glide :lol: but i guess rules are rules.
For cargo hauling up inclines it might even be worth considering a mid drive through the gears setup if they are legal in the EU. something cyclone like etc. I use mine heavily loaded with groceries etc and if you use the right gear it doesn't get the motor too hot even in a stiff head wind. Its nice to change gears and put the motor in a place where its happy rather than the compromise of a hub motor.

 

[SamTexas]

Have you considered the 9C 2807? Being a direct drive hub it should last a long time and should be maintenance free. It does not free wheel, but that should not matter with your very heavy setup, since you will most likely have the motor running all the time. I use one on a 26" wheel and the torque is more than satisfactory for me. I imagine that it would also be more than sufficient for you on a 20" wheel with a 25kph top speed. Regen would also augment the stopping power.

I'm a little confused though, are you using a 16" or a 20" front wheel? The simulation says 20, but the cargo bike says 16. In any case, it'll be even torquier on the smaller wheel.

Just curious, what are you hauling?

EDIT:
Never mind the 9C 2807. I missed this important part of your requirement:

[*]Pedal assisted transport of cargo uphill up to 10% incline.

I don't know if you can find a bicycle hub motor capable of pulling 300kg up a 10% incline. And even if such hub motor exists, the driving tire might not have the necessary traction. You might want to consider an all wheel drive setup.

 

[miuan]

Welcome Tom, have you managed to get in touch with the ev-power company? They offer bloody cheap ebike kits - I tried to contact a few of their staff per skype, but they've never answered. Good luck with the beast!

 

[Racer_X]

Welcome to the forum, I also live in Scandinavia, Stockholm Sweden to be exact.
I think that your plan is on the right track whether you get a geared torque motor (BMC V2 Torque)
OR even if you accept the advice of fellow members and go with Direct Drive motor which is cheaper and more reliable IMHO.

My biggest question is WHY pedelec? in my opinion it is not worth the trouble to install. Much easier to install a throttle only. and less maintenance issues.
Is it because of legal issues? At least in sweden it is no problem to have a throttle only ebike, the police is not interested in such minor issues (at least here in Stockholm).

Another question is why those batteries? Why not a Pingbattery.com they sell reliable 48v 20ah batteries, 48v 30ah batteries OR he can even build you a custom size battery and even custom shape (ie triangle, split in 2 etc. ).
This way it is just one battery with a BMS (battery management system) that you can just plug and forget.

For me the ping battery was the best beginner battery to start ever. Now I have learned enough about how batteries work that i am planning a Lipo build.
Good luck

 

[dogman dan]

This is the motor you want. but I'm not sure if Methys even wants to ship overseas. http://www.methtek.com/2011/11/12/2812-20-front-37/ Or you could run the 2810 which he also has. The slower windings of the 9c motor may be avaliable in Europe too, but I don't have the source found for you.

The last thing you want is the 2807 or 2806 winding. I personally have the 2810 winding on my frankenbike, a full suspension longtail cargo bike. At 36v it travels 15 mph, and 20 mph at 48v. ( in 26" wheel) I'd advise run 48v, so when you do climb 10%, you'll have a bit more wattage when you really need it. For the speeds you are targeting, a 2812 winding would be even better. A faster winding, such as the 2807 would just get hot and melt down going so slow.

Once you have the motor itself, then you can lace it into the rim you need. A 2810 in a smaller diameter wheel would be the equivilant of the 2812 in 26".

Pingbattery, in the size you require is a good idea. Iv'e had a lot of good service out of mine, and if , god forbid, you have a problem, Ping is the man you'll wish you'd bought from.

This is REALLY IMPORTANT. Whatever other motors people recomend, you want to choose the slower version of it. You'll melt down a faster version sooner.

 

[dogman dan]

Thinking some more, you might consider a rear wheel drive if you can get the 9 continent 2812 dd motor. You can add rear disk brakes to it, and still run a moped rim and tire for a tread diameter pretty close to 26" rim. At 48v, your speed would be just about perfect for your 25 kph. This way you'd be better off climbing a wet surface at 10%, have disk brakes front and rear, and avoid a radial spoke front wheel. You won't manage to get a big dd motor single cross laced in that small size.

But in a LOT of ways, you'd be much better off with a stokemonkey type drive that takes a motor, possibly a hubmotor, and chain drives through the gears. THAT is the proven cargo climber, and the first choice of the cargo bikes in San Francisco.

Unfortunately this is no longer in stock, but Grin is somebody you should be talking to. The best electric bike kit vendor in the world, who definitely ships worldwide. They may have some good suggestions too! http://www.ebikes.ca/store/store_stokemonkey.php

 

[kmxtornado]

May I offer another solution?

I had a similar dilemma. I wanted to be a rebel and ride a recumbent tadpole trike (two wheels in the front) with 1,992 upright cyclists on a trip from SF to LA. My trike was 45lbs and the roadies had bikes ranging from 16-27lbs. I didn't want to be left behind or have to give up on the first day of a 7-day ride b/c of hills. I had 1 yr to plan and made full use of it. This is what I did and how it can help you:

But first,
Perhaps consider an IGH (internal gear hub) from Sturmey Archer in the rear that's cassette compatible. You can match that with a geared hub motor in the front. This is my thought for my next setup until Sturmey Archer or SRAM come up with electric IGH's that are cassette/disk brake compatible for a full stealth look. Until then, my aforementioned setup might be a good thing for you. You'll be able to climb any hill with ease and the motor won't really have to be that strong. You'll have plenty of climbing capability with the IGH and cassette alone. Electrified, it'll be a bonus.

MY CURRENT BENT TRIKE SETUP IS A CLIMBING MONSTER:
My bent trike's got a Sturmey Archer CS-RK3 IGH in the rear matched with a 11-34T 8-speed megarange cassette. Combining this with a three chain ring setup in the front, 22/32/42, it's got 72 gears (overboard, I know), but allows me to get gear inches down to 8.9 on a 20" drive wheel. That pretty much means if trees were tall enough, I could climb one for hours. I've done something similar on my Aids Life Cycle ride, where I rode from SF to LA over the course of 7 days. I was paranoid about the 545 mile trek and spent a bit over a year and the above setup is what I came up with. No regrets. The hub itself is about $115. The expensive part was having the wheel custom laced by a shop since I don't really know how to do that stuff myself.

By improving the bike's drivetrain capabilities, you can rely less on the motor and therefore extend the use of your juice. With a cargo hauler, I assume you're going on more extended rides than the rest of us. I really recommend the above setup for that purpose. My trike's 45 lbs and it has no motor and no battery. It's heavy, but it certainly doesn't feel that way with the replacement drivetrain.

The best part of the IGH setup is that you don't sacrifice high gears to improve high climbing ability. Implementing this internal gear hub means you can up your high gears as well. You can check my trike blog for gear inch tables I made. If you're not much of a gear head and don't really care, just know that I went from a 76GI high to a 98GI high. It laymen's terms, that just means I can speed down hills faster than before.

PERFECT WHEN MATCHED WITH A MOTOR B/C:
1. Often times, the motor may not be strong enough to propel you at high downhill speeds. Gravity and momentum can be faster than motor speed. It's basically useless in this situation. An IGH will give you extra top gears for you to go faster. I rarely spin out going down hill on my trike. Unless I'm low 50mph (which I have, but don't recommend), there's always resistance which means you continue to have a high enough gear to bring you down hill at speed.

2. As I already mentioned, low gears are super important for uphill climbing - especially on a heavy weight bike such as yours. The motor should theoretically last long b/c you won't be using it as hard. The new drive train can do the work. Again, you can extend it's range by not utilizing as much (since the IGH when engaged in overdrive can drop all gears for improved hill climbing ability.

BENEFITS OF AN IGH SETUP:
1. Improves low gears for hill climbing
2. Improves high gears for hill descents
3. Perhaps lighter b/c you won't need as heavy duty of a motor to get up hills. The hub I have is about 3lbs.
4. Depending on exactly how you do this, you might break even or actually save money.
5. By improving your ability to climb hills by modifying the drivetrain, you won't need to rely on the motor. This will extend your battery range for sure.
6. This also means that if your motor/battery/controller craps out on you, you're still very capable of climbing hills which is probably very necessary on a cargo hauler.
7. It's just plain cool. Not many people have IGH's or know what they are.
8. IGH's allow you to change gears at a stop. It pretty much raises or drops your entire gear range by a certain percentage.

THAT'S NICE BUT WHAT'S AN IGH?
It pretty much gives you underdrive and overdrive for your bike. The internal gear hub I have has 3 settings that can be engaged from a stationary position. Neutral for flats, underdrive for downhlls and overdrive for up hills. The hub has 3 gears inside of it and basically allows you to drop the range of your current setup by about 30% or increase it by 30% (depending on the specs of the hub). This means your lowest gear gets even lower. Your higher gear gets even higher.

Some IGH's replace cassettes and limit your rear to 3, 7 or 8 gears. Other ones like the one I mentioned however is a bit higher end, (the Sturmey Archer CS-RK3) and is cassette compatible. That means you get whatever you have now plus the overdrive and underdive capabilities. The only thing you sacrifice is a bit less than 3lbs of weight and the cost for putting this together. And did I mention that this hub is only about $115 shipped from a member here on Endless-Sphere? The great thing about this is that you can use standard shifters. No proprietary shifter needed like SRAM's equivalent, SRAM 3x7 IGH hub. PM me for the ES member's SN if you want to get one.

CONCLUSION:
I would recommend an IGH for most applications, but it's definitely not for everyone. If you're a downhill racer on a carbon fiber road bike, that extra 3lbs amounts to a lot! However, it's perfect for folks like you who are already hauling weight and hill climbing is already difficult. Two reasons NOT to go through this setup:

1. If you calculate the difference in a smaller motor size w/an IGH vs a larger motor w/o an IGH and the numbers don't make enough sense. Ask yourself how much more you'd be willing to spend to get the extra edge.

2. You don't need range on the ride.

3. If you can already take hills easily and slopes really aren't that big of a deal, then an IGH would be a waste. I can't imagine this is the case for you though b/c if you're looking at getting a motor, I'm assuming you're looking for some sort of needed assistance compared to what you have now. Those that don't have high grade slopes should do w/o the IGH. The extra money and weight aren't worth it. For you though, I'd definitely get an IGH, hands down.

 

[Cargo_Tom]

Cheers for the feedback. It is much appreciated. Please tell me if my reasoning is weak. I am here to learn

crystalyte HT might do the trick, but a geared motor is always going to be better at climbing given the same amount of input power..
..If cost is an issue

Simulator play has the Chrystalyte front torque motor performing significantly worse than the BMC V2T. The Longjohn cargo bike is surprisingly stable at higher speeds when carrying cargo, but is very wobbly below 5 mph. My intuition is to value low RPM torque very highly, and from what I can tell, the V2T comes out ahead by a comfortable margin (at least compared to the other motors in the simulator)

As for cost, I'm not too worried about price margins. I'd prefer overbuilt to cheap any day. The V2T seems to have a solid performance from what I have been able to tell. But I'm happy to learn otherwise ofc

For cargo hauling up inclines it might even be worth considering a mid drive through the gears setup if they are legal in the EU. something cyclone like etc.

I will be playing with mid-drives later in my EV career I reckon. Needing to carry very heavy loads calls for power well in excess of 250w. But by keeping to 25kph and generally riding with the crowd I hope to stay under the radar and out of trouble. A hub drive should help with stealth as well. Denmark is almost as big a bicycle nation as the Netherlands, So I will rarely have free reign on the bikepath anyway.

Are you using a 16" or a 20" front wheel? Just curious, what are you hauling?

I don't know if you can find a bicycle hub motor capable of pulling 300kg up a 10% incline. And even if such hub motor exists, the driving tire might not have the necessary traction. You might want to consider an all wheel drive setup.

As for wheel size I am using a 16" moped rim. Add a tire and the wheel becomes 20". I apologize for the lack of clarity. As for cargo I am looking to replace a car, so I will be hauling the runt as well as the occasional heavy project item, like electromotors, hydrogen fuel stacks, fabrication materials, welding kit etc The bike needs to be able to fulfill all my daily urban transportation needs. So I need to plan for the heavy stuff even if I wont be needing that capacity all the time.

My commute is mostly flat with a short and steep climb halfway. If I take a small detour I can reduce the incline to about 5%, which would be much more manageable.

Welcome Tom, have you managed to get in touch with the ev-power company? Good luck with the beast!

Not personally, no. But some of the EV builders on campus have used them and recommended them as fairly inexpensive for what you get.

My biggest question is WHY pedelec? Is it because of legal issues? the police is not interested in such minor issues.
Another question is why those batteries? Why not a Pingbattery.com?
Good luck

Cheers. I'm looking for Pedelec with an override "fun" switch. This way I feel decently safe around cops. I will be commuting to and from university, where the police will have bike raids several times a month, doubly so during winter season. I want to look legal, even when the bike eventually gets inspected. As long as they are not sporting a multimeter I want to be able to pass initial muster.

As for battery choices I'm definitely open to suggestions. Choosing 12V batteries over individual cells reduces the number of units I need to worry about to 4. And I must admit that the lure of LiFe Yttrium chemistry is strong. Rock solid stability, superior temperature tolerances and 3-5k cycles is just dreamy. 'Tis a shame I cant find any as small as 20Ah.

This is REALLY IMPORTANT. Whatever other motors people recomend, you want to choose the slower version of it.
.. 9 continent 2812 dd motor...stokemonkey type drive... grin cyclery...

Agreed on winding type. Slow with lots of torque is the name of the game for tractor pulling.
And cheers on the motor suggestions. I'll take a gander and see if I can find some hard data on how they perform.

I'm hesitant about using a rear hub. The frame is 47 years old and was originally built as a fixie using moped parts. I have added an SRAM internal gear hub with coaster brake and that will serve me well for the speeds I intend to cover. I need to figure out if I can add roller brakes to that. If not I might change to an internal geared hub that can do disc brakes.

as for ebikes.ca I have every intent to give them some business. As a numbers guy the analogger+GPS is too good to pass up. I might also give the veloamp a whirl. Depends on the W.A.F. come january methinks (even though the veloamp does not help stealth at all)

I'll get back to you Kmxtornado. It is time to get the runt in bed :lol:

 

[amberwolf]

Given the room in that frame, and your need for really heavy stuff occasionally, and the need to get going quickly from a stop to avoid that unstable zone, I'd go for a thru-the-gears system (mid-drive).

Because of placement of some things, it might make the chainline a bit complex, but if you used an internally geared hub at the rear wheel itself, it would at least keep chain tensioners and derailers out of the picture. Since it was originally designed as single-speed, that would simplify things some.

There are a number of motor types you could use in the frame between your knees, but hubmotors (especially front types) are generally narrow enough to fit fine without issues. A geared motor would be smaller and lighter than a direct drive, diameter-wise, but either will work. The chainring ratios to the rest of the pedal drivetrain will choose how efficient each one is at the low speed startups and hillclimbs you would mostly need to worry about.

The disadvantage is that it makes the system more complex, and thus potentially more prone to breakdowns. But the advantages are that it can be more efficient because you can shift gears thru the IGH in the wheel to keep the motor speed faster even at lower bike speeds, and that it could be set up to pull better/faster from a stop to past the unstable speeds.

 

[kmxtornado]

I've laid out in my trike blog how I recommend designing your drivetrain with an IGH, but I can sum it up here.

The smaller the front chain ring, the easier it is to climb. The larger it is, the faster it will go down hill. But how small should your smallest chain ring be? And how large should the largest one be? I'm outlining it in a new thread here:

http://endless-sphere.com/forums/viewtopic.php?f=2&t=34267

 

[dogman dan]

About all you will find on the slow windings is my reviews, but I think Grin can give you an idea what values to put into the simulator to get a 2812 in 20" simulation.

http://www.youtube.com/watch?v=AfwdkfNZ7RQ
http://endless-sphere.com/forums/viewtopic.php?f=4&t=27364&p=395587#p395587
I can tell you it kicks ass on hills and won't get hot. Slow as hell at 48v, you'd likely want the 2810 winding for 20".

FWIW, no more torque than fast windings of the same motor. That myth is dead dead dead. But just not making heat so much instead of motion has a wonderful effect on hills. More importantly for those that want to ride slow, you have a short speed range, so the somewhat more efficent zone happens at a lower speed. Sub 10 mph riding up steep hills is possible, while fast hubmotors smoke themselves when crawling up a hill.

Even better would be a clyte 5305. That's pretty much gone, no longer made, stocks sold out, but maybe a used one eventually turns up.

Definitely see why no rear motor, no biggie till it's wet and you want to climb the hill. Enough cargo, and that won't be a problem. Dry, front hubs work fine. The IGH would be worth the compromise I'd think.

 

[SamTexas]

Cargo_Tom: If I were you, I would seek advises from people who have actually used a bicycle hub motor to pull/push a 650lbs two-wheel bicycle up a 10% incline. Or you could continue with this current plan and be prepared to take that short detour and only deal with the 5% incline. Anyway, best of luck on your cargo project.

 

[spinningmagnets]

Welcome, and I congratulate you on already doing so much good research before asking! If you decide to use a hub-motor in the wheel as it was designed to do, I would suggest that Dogman has the most experience with the various windings and their performance on steep hills.

If the short and steep section of road you have on your commute is usually dry and not slippery, then a front wheel hub would definitely simplify the drivetrain. Its difficult to say if the powered front wheel will slip on your particular steep section, so if you fear that, you may wish to try the more difficult rear wheel hub which has better traction.

Since you are willing to keep your speeds low, you definitely have the option of using a geared hub. I would recommend that you seriously consider the geared hubs because they are noticeably smaller, and are easier to make visually stealthy. The 9C looks big to inspectors. Geared hubs work well from 0-20 MPH (32 k/h), and suffer heat problems occasionally at the higher speeds. Direct-Drive hubs struggle at low speeds, and really shine between 15-30 MPH (24-48 k/h, plus they are quieter)

You mention that the bike will be inspected (hopefully by someone who is unaware of how much power a small motor can make!). I would recommend having TWO battery packs of 24V. They can be configured for 48V during normal operations, and for 24V when you are scheduled for an inspection (or just remove one). They may not measure the voltage, but if they do...a small motor with a 24V battery will make sense to their eyes.

I hope to have a mid-drive cargo bike someday, and here is a thread I started for various mid-drive configurations http://endless-sphere.com/forums/viewtopic.php?f=28&t=29176 If you want a smaller motor than the big 9C, but you like how quiet the direct-drive motors are, there is a new G-model as an option http://endless-sphere.com/forums/viewtopic.php?f=3&t=34203 Here is a post with some mid-drive links http://endless-sphere.com/forums/viewtopic.php?f=3&t=32220&p=466764#p466764

If you are good at bracket fabrication, here is an example of using a hub as a mid-drive. Sprocket changes are easier and cheaper than buying a different winding of motor.

 

[auraslip]

Ok - a lot of you guys don't have experience hauling stuff, and I do. Let me just say, REGEN is an amazing thing to have when you have a heavy load. If for no other reason than saving brake pads.

As far as torque goes - i wouldn't trust that BMC motor in a 16" wheel. I'm sure it'd be fine, but instinctively I wouldn't want to trust a plastic gear to push 600lbs at 140 Nm. As far as I know, no ones ever pushed a geared motor that hard.

I pulled a trailer with 200lbs of lawn equipment around all summer with a 9 * 7 (2807) motor in a 26" wheel at 48v, and it had plenty of power off the line. In a 16" wheel? It'd rock. And they're cheap and easily available.

Good luck. I'm excited to see how this turns out. Remember, simplicity is key to success. And overbuilding everything is the key to user enjoyment.

 

[Pure]

One issue you might want to think about before putting a hub in the front wheel is, frames are not meant to have that kind of force applied to them from that point. Most people get away with hub motors in their front wheels because they are not trying to pull 600+ pounds with their forks. Given enough time, I can see a catastrophic failure of the frame being a real possibility.

 

[dogman dan]

Possibly, but I suspect the frame on that type of bike is pretty beefy. Non suspension steel forks are pretty strong too. But snapping or bending the steer tube could happen. But the weight he's pulling won't matter that much in my opinion, if he's still only using 1000w of pull. See what I'm getting at? His hub is only going to pull but so hard.

Now if Luke was building this bike, the front wheel could launch leaving the bike behind.

Re spinningmagnets comment about stealth. Sounds like that could be a real issue, and another good reason to go with a chain drive, where you get the most out of 250w, or whatever your limit is. Unfortunately, you want a rear hub motor to do a chain drive. So if you get busted on the front motor, you won't easily be able to make it into a stokemokey like chain drive.

For inspections, if it's not suprise inspections, get a weak weak controller to pass the test, then use your 1000w-1500w controller for real use.

Is it about hiding the motor? or just meeting sucky euro ebike laws.

Auraslip is dead on correct that his 2807 motor could pull lots of weight. As I said before, the torque is nearly identical. The only advantages of the slow winding are cooler motor temperatures when pulling max amps at slower speeds, and a better modulation of low speeds with the throttle. Auraslip might have melted down a motor if he climbed a long enough hill with that trailer. Young and strong never hurts either. Dont forget though, put a 2807 in a 20" wheel, and it will behave more like a 2808 or 2809. Chances are, in 20" wheel most motors sold in 26" rims will work fairly good.

You'd only need the extreme low winding like 2812 for 26" wheels.

 

[snath]

BMC V2 from Ilia at ebikessf works just fine for my bicycle coffee roaster. 400 lbs loaded with a day's supply of green beans, supplies, and my butt.





This bike actually started out as a Long John http://endless-sphere.com/forums/viewtopic.php?f=6&t=16928&p=247441&hilit=snath#p247441

Larry Barefield

 

[jag]

Hi Tom,

I love that classic cargo bike and don't want to dissuade you from the build. However a 25km daily commute may not be ideal on it. After a while you'll probably long for a bike that is lighter, faster and more agile at swerving around pedestrians, bikes and cars. Think about it: How much does the extra commute time add up to over a year for instance?

What you want to consider is how often you actually ride with a load.
Here's my situation as an example:

Store (grocery etc)
Empty ride there (20%),
Around 10kg back. Fits in panniers and rack. (20%)

Commute
Ride with kid to daycare. Leave kids trailer there for wife to pick up kid in. 20 %
Ride empty to school, 20%
Ride empty back home. 20%

Haul furniture, Christmas tree and other big items, rare <1%
Bike trailer makes do with things as big as a double bed mattress set and headboard by folding down the kid cockpit and using it as a flatbed trailer.

So despite I use the bike for my all my transportation needs, most of my km's are empty (60%). The trailer does the kid and loads, and comes off when not needed.

I use a relatively light MTB that is quick and agile empty, and ok with the groceries on. (see below)

I would also consider a road or touring bike with friction drive if I wanted to go faster and the roads had smooth pavement. It is easy to maintain 30+ km/h on the flats and a 1kg friction drive + 1kg battery can take the drag out of going uphill.

Here's how I'm set up:
http://endless-sphere.com/forums/viewtopic.php?f=4&t=23518

 

[dogman dan]

On the flat? or on the hill? not knocking the gearmotor, just always want all the info.

One thing I didn't mention yet. In addition to regen possible, a dd motor also limits speed on downhills even if not using regen. So the slower the winding motor, the slower the fastest speed coasting down a hill gets. The motor will really resist going much faster than it's top speed. With 600pounds, it might not matter. Disk front brakes are going to be needed, and darn good ones too. 9c's mostly come disk ready now.

RE read aobut the inspections. I'm quite curious about that, what do the look for? Any motor? Overpowered motors?

Makes me start thinking about some kind of two controlers and secret switch arrangement. Pain so many wires to switch though. Ok off campus though, right?

 

[Chalo]

I don't know if you can find a bicycle hub motor capable of pulling 300kg up a 10% incline. And even if such hub motor exists, the driving tire might not have the necessary traction. You might want to consider an all wheel drive setup.

Front hub motor plus rear pedal drive is all-wheel drive, unless you lack legs or courage.

Chalo

 

[gogo]

Don't forget to plan for the 10% incline.

 

[Cargo_Tom]

In order of appearance:

Kmxtornado: Your suggestion is definitely elegant as hell. My local exotic bike dealer who has helped me restore my bike has warned me about standard bike components. The bike is designed to comfortably carry 260 pounds of cargo + rider. All drivetrain components are moped spec and fully loaded any bicycle component would be straining near their load limits. My 3 speed SRAM hub is specifically designed for cargo and tandem applications, so it should be able to deal with the added strain. I have a light cargo hauler planned down the road based on a Bullitt frame and your system seems like the perfect match for that application. Cheers

Amberwolf: A mid-drive system might end up being needed. I am not too keen on the stokemonkey system, as I'd prefer a freewheel between the motor and the pedals (or I'd go nuts). The Urbancommuter setup spinningmagnets mentioned in one of his cargo posts seems like a good contender, but I'd need to tweak it for a non-longtail system. Hiding it inside the cargo box would be ultra stealthy. Hmmmm.

Dogman: Thank you for the links. Nice vid, and excellent info in that review thread. I am not locked into using any set voltage yet. Would you say that the 2812 is a decent climber at 48 volts? Were I to up the voltage I could get by with fewer amps for say 1500 watts and thus lessen the strain on the electrical system, correct? (I understand phase wires tend to get somewhat warm when pumped with abundant current).

Samtexas: Cheers for that. I am here to learn so that I can make my practical mistakes in a more structured, productive fashion.

Spinningmagnets. Thank you for the links and the info. Seems longtails are gaining in popularity pretty fast stateside. Its all bakfiets and cargo trikes round these parts. Kidhaulers mostly. Ebikes are few and far between around here, as the dominating lycra crowd sees it as cheating. Some people, eh

Auraslip: Good points. The 2812 would score an extra point for regen. Stealth might be salvageable through wheel covers.

Pure: Good point. I wonder how such stresses would look in a fancy simulation. Am also curious what bike fronts would look like if designed specifically for powerful front wheel hub drives.

Dogman: I do not intend to limit myself to 250W. I reckon it is all about keeping physical appearences kosher. Single motor, Pedelec present (with override when cops arent looking) practical speed limited to the ballpark of 25 kph. Jobs done

Snath: That machine is a freaking work of art. Mmm coffee. Any hills round your way? My town is mostly flat with a 300 ft high plateau with our university sitting on it. No problem on my cannondale, but a pain with the unpowered cargo bike

Jag: Well I've got this old workhorse collecting dust and I'd like to learn more about electromobility in practice as it features quite a bit on my curriculum. My department has quite a few EV ethusiasts among the staff, and I thought that having some hands on experience on my own might get me some opportunities for latching onto some cool projects. The name of the game is car replacement for urban mobility. Doing this by bike also saves me the hassle of finding a place to park and rush hour traffic.

Dogman: Inspections are done by regular police. There are so many bicyclists here, that police tends to gather at bicycle hotspots and bottlenecks (like large factory sites and institutions of learning) to generate some revenue with alarming regularity. If you are a bicyclist you WILL get spot checked a couple of times a year. With ebikes being rare here in lycra-land I just want to maintain a veneer of law-abidingness for when the inevitable happens. Get busted and you get a ticket and told to remedy the situation. Get busted again for the same defects and they confiscate your ride.

Keep it secret, Keep it safe. Right precious?

Chalo: Yup. Being able to combine exercise with transportation is a godsend. I'd never move if I had to schedule exercise as a means unto itself. Getting powered means I can choose when to be soaked in sweat and when not to.

Gogo: the 10% is maybe a third of a mile. Combine that with less than full throttle and a helping of human power and I hope I can make it. If not I can replace the 10% slope with a mile and a half of 5%-ish slope.

I am grateful for your responses. There is lots to consider here. I have exams in January and hope to start the spending spree late january sometime. Fabrication should start around the same time so the bike can be ready for getting powered when components start showing up.

Cheers
-Tom

 

[auraslip]

Don't know how rigorous the inspection is. Someone sells "250w" stickers