Hub Motors for Cargo Bikes

General Discussion about electric bicycles.
mechanix   100 W

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Hub Motors for Cargo Bikes

Post by mechanix » Jan 11 2017 1:08pm

Hi all, I'm back from a 5 year hiatus - I had to scrap an electric motorcycle project in my senior year of college because I was starting to fail classes! I'm back now with a full machine shop at my disposal and wanted to start off with something simple and functional, so I'm thinking of putting a hub motor on a yuba mundo frame that I have lying around. I'm worried about the durability of a rear hub motor when the bike is loaded down with hundreds of lbs of unsprung weight riding down the pothole ridden streets of Portland, OR. I've done quite a few searches, but nothing has come up - anyone have experience with this? If a hub motor (the easy route) is not sufficient I could always do a mid drive, but I'm lazy... :)

The hub motor I'm looking at is the 4T MXUS 3000W V3

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Re: Hub Motors for Cargo Bikes

Post by Voltron » Jan 11 2017 1:52pm

One thing to check is the axle size. I don't know ofhand what hub motor has 14mm flats, but thats the dropout size on a Mundo. Otherwise you're going to have to make custom spacers or something.

That being said...My Mundo has been the most pleasant riding battery carrying monster ever...
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I liked it so much one wasn't enough :D
2fer.jpg
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The second one is still in the process of getting a frame mount motor with left side drive to the back wheel.

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Re: Hub Motors for Cargo Bikes

Post by amberwolf » Jan 11 2017 3:08pm

You might look thru my SB Cruiser thread for some usage info on that kind of thing.

The monsters in the foreground ride in the trike in the background
Image

Another POV, with one of the monsters in the background instead
Image

Wheel shot:
Image
the 9C will be replaced with an MXUS 3K/45 v2 as soon as I get the new spoke holes in the MXUS drilled to hold the existing Sapim 13/14butted spokes I'm using. Those are Shinko SR241's on there, cuz bike tires wore thru too fast and disintegrated, and also gave a crappy ride with that much weight. The Shinkos work fine and smooth out a fair bit of the smaller potholes.

Personally, I still avoid all the potholes I can, but it's not always possible; the wheels have survived fine so far.



CrazyBike2 uses the same rim/spokes on the rear wheel with an HSR3548, but am only using a bike tire on it as it doesnt' see quite the same loads or sideloading/sliding wear/scrub as the trike, but I've hit much worse potholes in it. I did break a rim (dented, tried to bend back, eventually cracked rim) but the spokes were fine and were reused on the new rim. :) Same thing would have happened hubmotor or not.


Everything is radially laced; no problmes from that so far.

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Re: Hub Motors for Cargo Bikes

Post by dogman dan » Jan 12 2017 7:47am

As you saw in the pic above,, a smaller diameter wheel than 26" for the win. So whatever you get, consider less than 26". This helps torque. Of course,, a 3000w motor has plenty of torque in any size.

My bike runs a pretty small ( 500w rated) low rpm DD hub motor, so it's performance slow. But when I load er up, it really pulls. The low rpm motor matches the speeds you can go with a big load and only 1000w of power better, so I can run very loaded at 10 mph without frying the motor.

This bike tried to imitate the edgerunner, big front wheel, tiny back one.
Finished cargo mixte..jpg
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As far as the potholes go,, a long tail does give you some advantages, since your body weight does not lift up on each hole or bump, but cargo does. If you load it with cargo like AW likes to,, then you will still need a high quality rim and spokes, and need to keep it tuned.

My other cargo bike takes a different approach. 26" wheel, and larger 5304 cyrstalyte motor, and 2000w. It can haul a large weight very well, like 15 mph up 8% grades, with 100 pounds of cargo aboard.
A schwinn cruiser longtail, 7-2015.jpg
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Re: Hub Motors for Cargo Bikes

Post by spinningmagnets » Jan 12 2017 8:34am

Add a temp sensor to whatever you try. As long as you keep it below 200F / 93C at the hottest part of the coils, it should be fine. That way, even if you determine you need something else, the existing kit will still be sellable.

As long as you will absolutely need two strong torque-plates, you can shape them to drop the axle three inches (approximately), allowing you to go from the stock 26-inch to a 20-inch diameter rear tire. If you go with a large direct-drive rear wheel (like the MXUS 4T 3000W you mentioned), I would use a 17-inch moped rim with DOT tire. The outside diameter of a 2.5 inch tire on a 17-inch moped rim will be around 21 inches. PM teslanv to get the true OD of a 17-inch moped tire.

This would mean you have to use a disk brake on the rear wheel (no rim brakes on a moped rim). If you go to the 17-inch rim, I'd spec the 3T MXUS if using 48V/52V. If using 60V/72V, I suppose the 4T would be better, but run the calcs to determine the best fit. If the temp sensor indicates that you are hitting high temps too often, add ferro-fluid, and although that is guaranteed to help the motor shed heat better...if it still needs a little more, add the rim-fins (I will add links to those threads here shortly)

"Wheel diameter to speed/RPM chart"
https://endless-sphere.com/forums/viewt ... 28&t=16114

"Ferro fluid / Statoraide"
https://endless-sphere.com/forums/viewt ... 5#p1114390

"Rim fins for large DD hubmotors"
https://endless-sphere.com/forums/viewt ... 0#p1207028

"moped rims and tires"
https://www.electricbike.com/moped-rims-tires-hubmotors

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Re: Hub Motors for Cargo Bikes

Post by Wheazel » Jan 12 2017 10:32am

I do have that particular motor on my cargobike nowadays. I run it on 18s.
However, mine is a long john layout and the weight is closer to the front wheel than the rear.
And in addition to this, I rarely load more than 50kg (110pounds) on it.
The bike itself is probably around 60kg (130pounds) with all the battery.
I am 73-77kg (160-170pounds) depending on gear. The wheel is a 19" moped rim.

95% of the items I transport are more bulky than heavy, but the vehicle is always 300pounds+ regardless.
Even transported a 2,5m (~8feet) tall apple tree plant once that wouldn't fit in my car.

What are you planning to put on the Yuba Mundo when you are talking hundreds of pounds?
I would not be too worried about the axle since you have the v3. I would just try it out.
Probably need to abuse it hard to make it fail.

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Re: Hub Motors for Cargo Bikes

Post by amberwolf » Jan 12 2017 3:01pm

If you load it with cargo like AW likes to,, then you will still need a high quality rim and spokes, and need to keep it tuned.
If it's built right (spokes thin enough to stretch as needed), you probably wont' need to do anything with it. I have not had to mess with mine except for replacing the one broken rim on CrazyBike2 (which probably wouldn't have failed if I had not straightned the little bent spot in the rim's edge, which caused a crack to start to split the flange away from the rest of the rim).

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Re: Hub Motors for Cargo Bikes

Post by ScooterMan101 » Jan 12 2017 5:20pm

Since you are ... Lucky enough to have access to a Machine shop .

Just make your Yuba Mundo a ... Rear Suspended one .

Is it the Aluminium Frame one or the Steel Framed one ?

also

The picture of the small hub motor in the blue frame a couple of posts above ( Voltron ), I have seen a youtube video of his bike going up some very steep hills just outside of Santa Barbara , California . I can tell that those are not hills they are mountains. he has a good combo for low torque , high pulling power.
As for me when I have to pull cargo, I just use my 36 volt / 30 amp 500 watt stand up scooter and pull my custom made flat bed trailer,
you can fit boxes, a dog cage, etc on it , it is slower than my bikes but I don't have to worry as much about the pot holes since I am going slower and just steer around them.
I have done much of what Amberwolf has does in regards to a flat bed trailer , not a cargo trike , with the scooter and have done a multitude of tasks with it.
I do use steel rims with spokes on the trailer, no longer using the plastic rim wheels .
My first conversion ...

https://endless-sphere.com/forums/viewt ... 1#p1077497

It's 2018 already, lets get some real , improved e-bike / e-velomobile / e-motorcycle designs .

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Re: Hub Motors for Cargo Bikes

Post by mechanix » Jan 13 2017 12:03am

Wow, thanks for all the responses, guys! Really good info! Looks like I'll be saving my Halo SAS 24" rim for another project - I don't think the spoke pattern matches anyways. I should probably start a build thread, or just post it in this thread? So far my rough plan is this:

Yuba Mundo Frame (the steel version - not chromo)
~20s LiFePO4 (around 1200 kwh) - is this still the best chemistry in terms of longevity and reliability?
4T MXUS 3000W V3 Motor with 17" moped rims
sinusoidal controller

I'd like to fit it all in the rear triangle behind the seatpost. I know this is less than optimal mass distribution, but this will be a fairly low performance build and I'd like to keep it stealthy. I don't plan on hauling huge loads all the time, but like to know the option is there without worrying about flats and snapping spokes etc.

Voltron - How many kwh is on that bike, holy cow!

-Joel

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Re: Hub Motors for Cargo Bikes

Post by Voltron » Jan 13 2017 12:23am

It's three modular 20s packs so you can switch it up for different range needs, 2 are 15ah, and the top one is 11ah, so about 3400wh nominal. Enough for 60+ miles of romping :D
117.jpg
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Short range beach party mode
397.jpg
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And passenger mode...
Last edited by Voltron on Jan 13 2017 1:28am, edited 1 time in total.

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Re: Hub Motors for Cargo Bikes

Post by Voltron » Jan 13 2017 12:47am

This is prob the video Scooterman mentioned.



To be able to do 2 straight hours of this kind of riding is really really satisfying and hypnotic :D
There's a nice ocean overlook at the end... and I started from where the white buildings are down by the beach..

The coasting back down actually feels like the sketchy part with the speed build of the hill pushing you in the turns lol



Good pothole action in the final minute... :)

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Re: Hub Motors for Cargo Bikes

Post by amberwolf » Jan 13 2017 1:50am

mechanix wrote:Yuba Mundo Frame (the steel version - not chromo)
Chromo *is* steel. ;)

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Re: Hub Motors for Cargo Bikes

Post by Voltron » Jan 13 2017 2:00am

True enough... but I think what he's getting at is it's one of the older steel, but not chromoly steel, ones.

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Re: Hub Motors for Cargo Bikes

Post by Samd » Jan 13 2017 4:20am

That rear wheel size will clownbike and drag the cranks.
Look at philistine's build.

I have a DD hub and a bbs02 on my wife's mundo. Bbs keeps killing the rear freewheel.


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Re: Hub Motors for Cargo Bikes

Post by dogman dan » Jan 13 2017 7:41am

Sounds like your wheel will be strong enough,, I only meant that if you chose the very cheapest amazon kit for a 20" wheel,, it would have a shoddy set of spokes and rim, and tolerate running with a broken or loose spoke very poorly. I tend to write for the 100's that will read this,, not just your specific build.

I have a pretty poor 20" rim on my bike, but mostly I don't load it with much more than battery, or a few groceries. 90% of the time I just pull trailers to do the big loads.

Nothing wrong with your plan,, that strong a motor won't need a small wheel. Just a lot of amps to fly up hills without lugging it enough to overheat it.

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Re: Hub Motors for Cargo Bikes

Post by Voltron » Jan 13 2017 11:17am

Re the small wheel, with the 55 tooth front ring on there, you can pedal effectively at 20 to 25 steady, and up to 28 or 30 mph in a burst... its actually geared perfectly for helping the motor accelerate out of the turns during the steep climbing (esp with a passenger). You can hear the hard pedaling in those vids because of my stretched out chain...
And with the long tail of the Yuba frame, the bottom bracket is lowered less compared to the same drop of the rear end on a short tail frame, so there's plenty of pedal clearance (on road anyway).

That being said, when I had the same motor on a short full suspension frame with a regular MTB crank, it was clown pedal/pedal strike city! :D

BTW, not advising everybody to go THAT small... it started out just throwing that motor I had laying around into a frame as a lark to see how it ran. And it ran well enough to make it worth evolving it into something getting tolerable pedaling clearance and effectiveness.

Compared to how it started out as a short little, pedaling optional, 2wheel go cart wheelie machine, it pedals great! lol
087.JPG
But having added 9000+ miles on a used motor with no spokes to break (the cast wheel makes a great heat sink too) and still on the same original brake pads has an appeal.

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Re: Hub Motors for Cargo Bikes

Post by dogman dan » Jan 14 2017 7:38am

Re clown pedaling. The first and foremost criteria when I built my home made edgerunner, was that the bike frame must clear my 56 tooth crank. I can pedal at a reasonable cadence up to about 20 mph on it. 20" wheel, 56-14 gear. BTW,, that pic shows a 48t.

Since I was building the frame,, I put the pedals high enough to corner hard while pedaling and never strike. I slacked the mtb heatset angle to cruiser in the process too. I also made my bike a bit shorter than a Yuba. Just short enough to be possible to carry it on my swagman bike rack. But longer than normal bikes for sure, for the better ride and ability to pack a battery between the seat and the wheel.

With a long enough bike like the Yuba,, longer than mine. you don't change the heatset or the bb height that much. Put a shorter crank on it if it does strike.

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Re: Hub Motors for Cargo Bikes

Post by mechanix » Jan 15 2017 1:39pm

I've spent hours and hours researching and settled on the following components:

Moped Rims and tire - Thanks for the link, spinningmagnets!

24S1P A123 20ah prismatic cells -Is there anywhere to get genuine cells at a good price? Or even have a pack built for me with genuine cells? There's quite a few vendors out there that say they have A123 cells and packs, but I don't know who's legit. I'd rather not mess with this part if I could get a solid pack built that had heat sinks like the A123 packs have. Do they still sell those packs?

4T MXUS 3000W V3 Motor - Where can I buy this?

Sinusoidal controller - Anybody have experience with powervelocity.com controllers?

Charger - What's a good charger that balances while charging? The last project I did had four Hobbyking chargers and four power supplies in a suitcase...

I'm ready to buy all this stuff to get this project moving forward, but cannot for the life of me figure out where to actually buy some of these things! I'm also worried about if I will actually get genuine A123 batteries, as I want to be able to use regen and charge them fast without affecting their service life. I'd love to still be using this bike 15 years from now!

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Re: Hub Motors for Cargo Bikes

Post by amberwolf » Jan 15 2017 2:40pm

mechanix wrote:
24S1P A123 20ah prismatic cells -Is there anywhere to get genuine cells at a good price?
A123 themselves actually sell the cells, thru their Stortronics site; it's the only place guaranteed to have the genuine stuff. :)

Or even have a pack built for me with genuine cells? There's quite a few vendors out there that say they have A123 cells and packs, but I don't know who's legit.
I don' know if they still do the pouch cell packs but EM3EV did have the real deal (I have one of them here).

4T MXUS 3000W V3 Motor - Where can I buy this?
I've seen some in the for sale section now and then, usually in the Used category. (is how I got mine).
Use this search
https://endless-sphere.com/forums/searc ... mit=Search
to list all the stuff with MXUS in the title in both new and used section, and just keep checking it until you find one you want. :)

Charger - What's a good charger that balances while charging?

If you have a pack built, and use a BMS, you won't need a balancing charger and could just use something like the weatherproof Meanwell HLG LED PSUs as a charger, or if you want more versatility (but at a higher cost) there's the Cycle Satiator from Grin Tech (which is also weatherproof, or as close as you'll probably get in a good versatile charger).
I'd love to still be using this bike 15 years from now!
Aging of cells will probably negate using the same battery for that long, unless you start with a pack that is at least several times the size/capacity that you actually need, so that A) it's shallowly discharged, and B) will still have the C-rate you need even that far down it's lifespan. Cuz for example with my first EIG NMC pack, it's aging (maybe 6 years while I've had it? was used when I got it) has caused it to sag a fair bit more than it used to under load, but it still provides the same total capacity it did originally (or so close it doesnt' matter).

But you can still use everythign else, and just keep adding to or replacing the battery once it no longer does what you want.

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Re: Hub Motors for Cargo Bikes

Post by mechanix » Jan 17 2017 12:34am

I've found a way to source everything except for the batteries and the hub motor.

I've decided, and my wife agrees, that I'm going with LiFePO4 chemistry due to less chance of a fire. I've contacted Victpower on Alibaba and they quoted me $15/cell for (50) pieces of 30ah prismatic cells (yes, 30ah - some cells would be for my next project). No idea what shipping will be but I'm thinking it will end up being $20-$30 per cell shipped. These cells would see bursts of 3c during acceleration, and a little over 1c during cruising speed of around 40mph. I have no problem paying more for quality that will last longer, but it seems that you never really know what you're getting when it comes to batteries...so I guess our only option here is to pay dirt for $h!t cells, knowing full well that you're getting what you pay for...Is there really no way to purchase a battery and know what you are actually getting, where it comes from, and if you will actually get it? I would gladly go to a123batteries.com (stortronics) and buy (24) of the 20AH cells, but people are saying those are a crap shoot as well... here's the link to the ones I'm looking at:

http://www.victpower.cn/product/6019435 ... ttery.html

Has anyone on this forum used knockoff A123 cells for more than a few years without them crapping out? It seems like the best case I can dream of is 5 years if I'm super careful and lucky to boot. I'm hoping that the large capacity of the 30ah cells would decrease the c-rate enough that they could last a decent amount of time. I plan on babying the cells, and keeping the correct pressure on them, keeping them balanced, and even having a few on hand in case some of the cells crap out, etc...

As for the MXUS 3000W V3, is there really no way to buy this motor? Why is everyone talking about it if you can't even get it? There has to be a way to source this motor...

So close! Thanks for the help thus far, guys!

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Re: Hub Motors for Cargo Bikes

Post by Wheazel » Jan 17 2017 2:14am

The mxus can be bough from several places afaik.
In the us some place called Kinaye motorsports if my memory is correct.
In the EU Allex on this forum sells them I think.
They can also be bought directly from asia.

Regarding victpower, I have only heard bad things over the past few years.
No personal experience.

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Re: Hub Motors for Cargo Bikes

Post by amberwolf » Jan 17 2017 2:51am

Stortronics is selling the direct from factory cells, so those shoudl not be a crapshoot. They should have a warranty as well, which you won't get from somewhere else (well, they may offer one but since you can't ship batteries (by air at least) unless you can get someone to do it for you that has UN certification, it's tough to get them back to them for warranty. (unless they'll just send you new cells without getting the old ones back). The only report I recall on ES about a problem with Stortronics cells was eventually resolved with zero cost to the buyer.


I would guess that for the crapshoot cells, you might be seeing reports of cells from places like OSNpower, victpower, etc., where they are selling what are almost certainly recycled / scrapped "A123" cells. There are some reports that places like that sell "fake" A123 as well, though I don't know if that's true or not.



Regarding the Victpower cells you link, note the pic they show of using bubblewrap to store (and presumably ship) them in, without any kind of packaging to keep them flat and unbent. If they get bent up they aren't going to operate like they should, at least not for as long as they should.


You can search the forums for "victpower" or other places like OSNpower, and see some of the reports about them; good and bad.

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Re: Hub Motors for Cargo Bikes

Post by mechanix » Jan 21 2017 7:28pm

Alright, getting closer! I contacted a few different vendors regarding the material and I got a quote back from http://www.mxusebikekit.com for $650 shipped (I was talked into buying two in order to make better use of the shipping, so there might be some stuff for sale soon) :

(2) MXUS V3 Hub Motors
(2) 96V (18) IRFB4110 sinewave controllers with regen/throttle/tap

Anybody have experience with them? I plan on paying with Paypal, is there any risk in that? I feel like that's a decent price - not looking for rock-bottom prices, as I want it now :)

As for the batteries, I don't need anything super high-performing, but would like them to last a while. I'm thinking that a properly-made pack of Victpower 30AH could last 5 years or so, since my cruising amp draw will probably be around or slightly above 1C. I'm not expecting A123 performance - I'm hoping that better technology will be out in 5 years or so. It will be around 1900 kwh of batteries.

I got a quote for Victpower for $750 for (50) 30ah cells. (20) will be used for this project, the rest will be for another project and spares in case a cell craps out. This is not including shipping, which I'm assuming will add quite a bit to the final price. Anybody use Victpower recently?

Thanks for all your help thus far!

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Re: Hub Motors for Cargo Bikes

Post by dogman dan » Jan 22 2017 8:03am

Uh,, depending on the weight you load on a cargo bike, or tow, and the hills,, you can pull a heck of a lot more than 30 amps cruising.

So uh, maybe 40 ah would be better,, by buying 20 ah cells?

I think in some situations you will need more than 30 amps, for long enough for the cells to not like it. Just saying,, big motors with big magnets can suck hard on your battery real easy.

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Re: Hub Motors for Cargo Bikes

Post by mechanix » Jan 22 2017 1:00pm

Yeah, I guess you're right, Dan - Are there any batteries that are decently cheap that would be happy in this situation? I though long and hard about the A123 cells, but I can't deal with the $0.75/wh, when there are knock-off lifepo4 cells for $0.15/wh (before shipping). Will probably

I like the idea of the 30ah cells because all the cells would be in series and I would truly know what's going on with each cell in the pack. And I guess I'm kind of stuck on lifepo4 technology because of the supposed safety compared to the other lithium technologies.

As far as thermal management for the batteries goes, has anyone ever used non-electrically conductive thermal paste to keep pouch cells cool? As far as I could gather - the main reason low quality cells have low C-rate ratings is because of their high internal resistance (heat). If this could be managed - you could substantially increase the performance of cheap cells, correct? And perhaps increase their service life as well?

-Joel

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