E-bike noob after cargo bike advice

Hello collected wisdom of Endless Sphere!

I am after advice before purchasing my first e-bike kit.

I have just bought an early model Yuba Mundo (V2) Cargo bike with the intention of electrifying it to make a cargo and child carrying electric vehicle.
My research so far has me leaning towards installing a MAC 10T or 12T hub motor in the rear wheel (ALEX DX32), 48V/50V battery, 9 FET controller from Paul at EM3EV.

My commute is a 10 km round trip, with one serious hill but mostly flat. I am a strong cyclist, but would struggle to get up the hill on the heavy 6 speed Yuba, especially loaded. I realise the system I have proposed might not meet my countries regulations, this is a problem that I am prepared to accept. The bike has huge pannier bags that would hide any sign of the hub motor. Has anyone replaced the rear wheel of a Yuba Mundo with a MAC powered wheel? I have seen lots of amazing mid drive systems, but I think for simplicity I will use a hub motor.

Any advice or alternatives you can suggest would be appreciated.

I have a Yuba mundo that I put a 350 watt front hub kit on with a 48 volt Allcell battery. It worked great for a few thousand miles and still does. I get up to around 50 miles out of the battery even with moderate hills. You do need to pedal though. I recently added a Bafang Mid Drive 750 watt kit so i could have a sort of dual redundantcy system. I just did a 40 mile organized hilly ride and passed everybody on the hills with the mid drive. It allows you to utilize the bikes gearing for much better power on hills without killing the battery. Highly reccommended.

Make sure to get the temp sensor on the motor, and a Cycle Analyst V3 which makes it easy to set limits on the amps going to the motor based on the temp of the motor (roll back amps at 140F/60C, cut all amps if it gets to 200F/93C). Start with 30A, and let the CA roll them back automatically if needed...

If you are adding pedaling, you will be fine. If the power starts getting cut back on the hill (your hills may be steeper and longer than my hills) then you might need a bigger hub and more amps.

A second option is to get a 10T MAC, and if it is struggling on that one hill...get a second 10T MAC for the front (of course then, you lose the stealth).

For a truly silent system, get a 3540 rear hub using a sinewave controller, hidden behind the panniers, and using 40A. This would also give you a regen "magnetic brake" on a downhill...keeping your bicycle brakes cool and ready in standby. Here are some 2WD builds:

http://www.electricbike.com/custom-build-gallery-teklektiks-dual-motor-yuba-mundo/

http://www.electricbike.com/custom-build-gallery-duty-cycle-awd/

http://www.electricbike.com/custom-build-gallery-zlatkos-mental-manno/

Thanks folks!

I don't think I'm quite up to 2WD yet :wink: trying to keep things simple.

The Bafang BBS02 750W Mid drive is a very interesting alternative suggestion. It uses a bigger chainring, so I'd have to either push harder or fit bigger rings/IGH to the rear of the Mundo if riding unassisted. Any advice re durability of the Bafang vs MAC 10T/12T?

I wish I had a bafang bb to test on my cargo bike. I'm dying to see how rugged they are. For climbing a hill slow, nothing can beat a through the chain drive. For a dual setup, a small gear motor on the front wheel and a bb drive would rock IMO.

But they are just too new, so nobody has really put them to the test yet. If you are willing to wait another month or so, others will start reporting if they melt.

My own cargo bike has the second best solution circa 2008. The no longer made crystalyte 5305. Freakish heavy, but unbreakable when run at 2000w. And 2000w gets me up the rocky mountains fully loaded, at 500 pounds of bike, me and cargo. As others pointed out, two motors also gets you to a reliable 2000w.

The BEST solution for cargo bikes has not changed, it's the stokemonkey. Get it from Grin cyclery, but it's not cheap. That's why I don't have one.

If I was you, starting from scratch, I'd start with the bb drive. If it's not enough, add a tiny gear motor you use only on the steepest of hills to get speed back up to 10-15 mph. A very slow rpm gear motor.

But to be fair, a Mac 12t or 10t will do the job fine as well. As would just about any hubmotor with 1000w. Before I got the big 5305, I ran my cargo bike fine on one ordinary motor.

And if you have money for the best, go buy a stokemonkey.

Hi,

http://www.ebikes.ca/news/RSD-Stokemonkey-Kit/

Right Side Drive Stokemonkey Kits - Available Now
April 28, 2014 2:57:00 AM PDT
The Right Side Drive (RSD) Stokemonkey system has been refined after months of pilot testing, retooled for the new 2014 Edgerunner frames, and is now available as an independent conversion kit.


Some of the great features include:
V3 CA with built in pedal torque sensing through the clampset, for proportional torque assistance and human power readout
Patterson 2 speed crank with custom 39T chainring, both freewheels and provides a 62T equivalent front gear letting you pedal along at high speeds even with the small 20" rear wheel.
All cables lengths sized for a perfect fit on both the large and small 2014 Edgerunner frames, with all wires routed on the downtube for a clean install.
Works both with rugged internal hubs (like the Nuvinci) and regular derailleur gear systems.
The installation of this kit is a bit more involved than hub motor setups since it requires bottom bracket tools for the Patterson Crankset, but shouldn’t intimidate the mechanically inclined. At the moment the kit is only sized for the Xtracycle Edgerunner frame, adapting to other bikes could be tricky but we are working next on a Yuba Mundo package.

Click to expand...

http://www.ebikes.ca/shop/conversion-kits/stokemonkey/stokersd-er-kit.html

RSD Stokemonkey Kit for Edgerunners
Availability: In stock

US$1,495.00
Price as configured: US$1,495.00
Quick Overview

Complete Right Side Drive Stokemonkey Kit for Edgerunner Cargo Bikes with Torque Sensing

Click to expand...

Welcome to Mundo World!

First - you have a V2 which is a very heavy bike - well over 50lbs bare. These early models had a lot of struts all over the luggage rack that were later removed and the frame tubing was thinned a bit. This gave a lighter bike with more usable frame space in the rear for slide-in batteries, mid-drive, etc. One of the features that stayed was the 48 spoke rear wheel with 14mm axle - a real cargo-hauler.

Some thoughts:

• Your needs seem modest and the terrain seems unchallenging, so you seem to have no reason to look at 2WD. That's a whole other issue, and Bad 2WD Advice is too easy to come by....
• You mention going with a rear wheel drive. This is fine, but realize that you will lose the 48 spoke rear cargo wheel and will need adapters to deal with the 14mm dropouts. This is a bit of a PITA. You can go all custom, use Kiwi's plates, use the Yuba Washers, or some combination. But it's definitely not a normal bolt-up arrangement.
• Another option is front wheel drive. I have ridden many thousands of miles on a Mundo running FWD with no issues at all. The bike is so heavy that wheel spin is not an issue on paved or hard-pack. However, you have a picture near the sandy beach and that would be a deal-breaker for FWD. If you are staying out of the sand, FWD offers a simple conversion and lets you keep that heavy duty rear end. It also moves a bit of the weight up front. I regularly dump 2kW in FWD on pavement through the equivalent of a MAC 8T at 66v. The MAC is a fairly small motor and is not really too noticeable up front. Most of the cyclists I meet don't notice the bike is electric (with two motors no less) and those who 'know' about bikes sometimes ask about the big 'drum brake' I have up front.
• Since you have a V2, you also have a couple of unnecessary struts aft of the BB that fill up the space between chain and seat stays that is the usual home for a Stoke Monkey (see the image in the OP). Unless you are going after metalwork or trying to squeeze the SM into the tiny triangle - the Stoke Monkey is not a consideration.
• A Bafang crank drive might be an option, but it will certainly eliminate the 'stealth' aspect of your build. Other than that, it would be interesting to see.
• Since you mention carrying kids and cargo and a hill (no details), I'm guessing you aren't too interested in speed. Frankly, a MAC 8T will haul that bike nicely over low rolling hills (about 29mph on the flat) and will give good assist up an 8% grade (it will be working towards overheating, but a CA V3 with temperature rollback addresses that). A 12T will climb 8% all day without overheating and will do about 23mph on the flat.
• Here's a comparison using the ebikes.ca simulator of top speeds for a 12T on the flat and on an 8% grade with an 80lb bike and 170lb rider. You'll lose about 1.5-2.0 mph on the hill with an extra 80lbs on board. The BMC V2S and BMC V2T are roughly equivalent to a MAC 8T and 12T respectively.
  
  
• Realize that at low speeds, the motor/controller is limited by the controller (left of the peak in the red line above). A 12 FET controller will give you some extra torque if you are looking for more assist on getaways or if your hill is bigger than 8% or so (you can play with the simulator to see this). This is less of an issue with the 10T/12T which draw fewer Amps which makes the 9FET look somewhat more attractive in those cases.
• As mentioned above, get a CA V3 - this will give you throttle ramping which will help save your clutch on getaways with a heavy load. The temperature rollback is a plus if your hill is massive, and the Current Throttle will generally give you nicer throttle control.
• Unless you are looking for speed (8T), the 10T looks like a good choice for cargo hauling mostly-on-the-flat, but the 12T will clearly give you more boost off the line if you are crossing intersections with a big load. Any of them can handle a pretty fair hill, although the 8T will be warming up if the hill is long or huge and the CA will cut your speed appropriately.

Teklektik always lays out the clear truth. He's the specialist with the sick Mundo, so I'd take his advice.

One thing I do disagree on is the stealth of a Bafang bbs. With a large chainring up front, they are almost hidden from the right side and hard to notice on the left. They are also much quieter than you would think.

It actually takes me a little more time to identify if a bike is has a Bafang bbs on there than if it were to have a hub motor.

Here's a video that does good justice to the bafang's stealth:

[youtube]RK38Nw_KNmY[/youtube]

Wow! You guys rock.

I am amazed at the thought and time that you have put into replies. A few excellent points made-

Front hub motor simpler to install than rear hub motor with the Mundo's 14mm axle. I had assumed that a stock torque arm would do the job but can see how a solution like the washers that Kiwi engineered is the go.

Stokemonkey is the bomb. Obviously. And $. But my early V2 Mundo has lots of steel behind the seat tube where the mid hub motor would be mounted. I'm not too concerned about taking to the thing with a grinder/welder, so far this bike owes me $109-, $100 for the bike and $9 for the new blue grips I fitted on the handlebar for the passenger. Hub motor mid drive might have to wait for a Mundo V4 (or 5) frame build, later…..

Bafang looks like a good option, the bike has a pretty agricultural crankset with fixed (welded!) chainring, would be no loss. My only concern really is how new the BBS02 is, there is not as much information out there from real world users as the tried and tested hub motors.

cal3thousand - I've already watched your videos, nice build, thanks for the advice. I don't think the Bafang would look out of place on a bike as weird looking as the Mundo.

teklektik - truly, you know what you are on about. You reckon something like front drive MAC, 10T would be enough windings, CAv3, 9 FET, 50V 14AH. Or Bafang BBS02 if I'm feeling adventurous. Thank you for the detailed reply. I will read it through again, a few times



I must say, I'm leaning towards the Bafang Mid Drive. How do I choose the right battery? Seems like the only variable.

cal3thousand said:

One thing I do disagree on is the stealth of a Bafang bbs. With a large chainring up front, they are almost hidden from the right side and hard to notice on the left. They are also much quieter than you would think.
....
Here's a video that does good justice to the bafang's stealth:

Click to expand...

Excellent video! I take your point about the stealth - the quiet running is impressive. At low speeds it's almost impossible to hear my bike but at 35-40mph it sounds like a giant PO'd Killer Bumble Bee . I guess the visual impact is a matter of personal taste, but I'll certainly admit the Bafang is not very intrusive.

T-Dub said:

Bafang looks like a good option, the bike has a pretty agricultural crankset with fixed (welded!) chainring, would be no loss. My only concern really is how new the BBS02 is, there is not as much information out there from real world users as the tried and tested hub motors.
...
You reckon something like front drive MAC, 10T would be enough windings, CAv3, 9 FET, 50V 14AH. Or Bafang BBS02 if I'm feeling adventurous.
...
I must say, I'm leaning towards the Bafang Mid Drive.

Click to expand...

I would be very interested to see such a build - a big plus is that it keeps the rear wheel assembly intact. Ilia at Ebikes SF has built up some bikes with this and is impressed and Paul at EM3EV carries them now. These are two well respected ES member/vendors with outstanding product support reputations - it says worlds if they like 'em and sell 'em.

Another option would be to go with Lightningrod's Mid Drive kit (Website). This is very new and lacks the integration (PAS display, etc) of the Bafang, but is in a whole different power class. Really excellent design work with amazing fit and finish - intriquing - I'm mid-stream in a hubbie build just now and am seriously thinking of switching horses to give this thing a try...

The local shop here in Iowa builds an electric Mundo every week and has switched exclusively to the Bafang 750 watt mid drive. The only issue they have had is with the owners build that has a Nuvinci rear hub. It seams that the hub doesn't like being fed with 1 horse power

They have built a Fat Tire Mundo recently...very cool. It has a Bafang with a Rohloff gear hub.

Thanks for the help folks!
I've been in touch with cell-man and have just ordered the BBS02 with the 50V 12.3 AH triangle battery.
I've also seen a few builders replacing the spider on the Bafang to take standard 104 BCD chainrings, I think I'll look into this, the mundo has I think a 38t ring at the moment, so I'm not that keen on replacing it with the 48t ring of the bafang, there goes my low end if riding unassisted. No doubt the torque is more suited to a cargo bike if the bafang were running a chainring smaller than the stock 48t.

Just a bit of a progress report incase it is any help to somebody-



The Yuba Mundo V2 has a steel bottom bracket shell with unmachined steel in the centre, the diameter too small to fit the Bafang BBS02 through.
I bought a 33mm hole saw, which fairly quickly cut away the excess steel without damage to the bottom bracket threads. A little clean up with a burr file and the BBS02 was a neat fit.
I fitted the BBS02 with the 104mm BCD spider from hi-power cycles, a 39t chainring and a bash ring from a DH mountain bike.
I also found a 26" Nuvinci wheel for sale in the classifieds for a great price, which posed its own set of problems.
It is the original Nuvinci, 170S. The Yuba Nuvinci adaptor plates suit the new Nuvinci N360, and suit the 10mm left side of the 170S. I machined something similar (a no turn washer) from 3mm SS to suit the 14mm right side axle of the 170S. 18t freewheel on the Nuvinci.
This wheel has been laced in a 2x pattern which puts the spokes at too great an angle as they enter the rim. I will rebuild it with a 1X pattern.
A longer set of shifter cables is on the way.

It looks like I can do without a chain tensioner, there's just enough adjustment in the Yuba drop outs, but I'll fit one if necessary.

The battery is held up in China, but hopefully it won't be too long. Itching to see what this thing can do!

Looking at fitting either Maxxis Hookworms or Schwalbe Fat Franks to this, any recommendations?