Which kit for mini velo cargo bike

[la838]

Hey everyone, I'm building a cargo bike out of a mini velo bicycle, using a xtracycle kit, so it'll be a long tail bike (will look a lot like this one but a little longer. Since is a mini velo the wheels are 20 inches. I'm looking at a rear hub one so just wondering what volt and wattage I should be looking at.

Speed is the least of my priorities, I'm not making deliveries with it plus I don't like going fast with cargo anyways. I'm not planning to move a lot of cargo either, at most 20kg worth, I weigh 55kg, so let's say about 75kg (165lbs) together. Is mainly flats where I ride, with some 5% inclines here and there. So I was thinking maybe 24v or 36v & at most 500w? For battery, since I don't need to go that far with it at the very most total of 30km, a 10-15ah battery would be fair for this? Though yeah I really have no idea if I'm on the right track, so I'm keen for any advice!

I'm located in Australia but don't mind getting a kit from China. I'm keen on this leaf bike kit, or maybe a mac motor from Em3ev. For battery I'll most likely get this one locally to save on shipping fees for batteries from overseas.

So just wondering if I'm on the right path with the volts and wattages, if you guys have better suggestions for what I should get I'm all ears!

 

[dogman dan]

Since you and your cargo weigh less than I do, your total weight should be well under 300 pounds. (bike, battery, motor, cargo and you)

That makes any of the 500w rated motors a good choice. Note, I did not say 500w. I said motor rated 500w. This category includes the mac, and all the lower power direct drive motor kits out there. 36v will be enough speed, but you do want a controller with it that will produce enough watts to maintain your speed up those 5% grades. Though a smaller 350w geared motor kit would work, ( that leaf kit) you will be much better off with a 20-25 amps controller on a larger motor. Such a kit would have a 500w rated motor, and the typical 22 amps controller would give you 800w when running 36v. Top speed would be around 20 mph, a bit faster at first when the battery is full, and more like 18 mph as you finish.

You could also get er done with a mid drive, in which case even the smaller 350w kit would do.

 

[la838]

Ah thanks for the info, as far as direct drive motors goes. What do you think of this kit for my uses? I have some concerns about it, mainly just too much power and going too fast on it and I'm just curious if I'm able to can limit the top speed on something like this when I'm just using using the throttle on it. Though the price might be too good to ignore as it includes a Samsung battery. Since this would cost me the same as getting a Mac motor kit shipped here and I still have to spend for a battery for that.

 

[Drunkskunk]

Welcome to the forum. yeah, you're on the right track.

500w seems like a good target for your stated needs. Forget 24v for several reasons, it's just not really a viable option. 36 volts will get you what you need out of the MAC motor. And the MAC motor is a very good choice for what you're trying to do. Possibly the best possible choice.

The other real options are a direct drive or a mid drive. A direct drive hub has a few advantages, but a few real disadvantages in your application. all of them on the market right now are larger diameter than the MAC, making the spoke angles a problem on a 20" wheel. While The motor would be fine, the wheel would be weak, and that isn't what you want on a cargo bike. It would likely become a high maintenance source frustrations and colorful profanity.
The mid drive would work well, but it's overpriced over-complicated overkill for what you need. Mid drives give very good torque multiplication at the expense of being more complex to use and maintain. But for >100kg of bike and cargo on relatively flat ground at low speeds, there aren't any advantages over a good geared hub like the MAC.

Range is dependent on speed. with a slower MAC 10T you could do just over 30Km on a 36V 10Ah battery going flat out, which is about 25kph for that motor/voltage combo. Using a MAC 8T, which can hit 30kph, and you would run out of battery at 25Km. But draining your battery flat is a very bad idea. I would add 50% more capacity to keep a reserve and to keep the battery happy. The care and feeding of Lithium batteries is something you'll want to learn. And that means the battery you picked from Luna would be just about right. 36V 15Ah. it would take you 30Km at 30Kph with a comfortable reserve.

you can play around with this simulator to see how your bike would perform with different batteries and motors. The MACs are buried in the motor list. at the bottom of the list is option to SHOW ALL. The MACs will be in the list after you hit that. You can also build a custom battery to the voltage and Amp hours you want, to better match what you find available.
https://www.ebikes.ca/tools/simulator.html

Paul, the owner of EM3ev is a member of this forum. And he's in my top 5 companies to deal with for anything Ebike related. The MAC 10 is probably the single best option for this kind of build. I've not dealt with Luna personally, but they have a good reputation in the community. They build their battery packs from real and name brand cells and are pretty transparent about it. this is not something most companies do, and people have burned their houses down from cheap and questionable batteries. Leaf makes an OK geared motor. they are better known for pretty good direct drives. It's not a bad kit, but the MAC motor is so much better of a choice that Leaf really isn't worth considering. Not really enough power, not realy robust enough to handle being on a cargo bike, not really the best option in a large sea of other options before you got to the MAC. Dillenger AU... well, maybe you might want to do some very careful research on them... At any rate, you pretty much nailed it with the MAC motor from EM3ev and the battery from Luna, so maybe you don't need to worry about them.

Now this next part is just my opinion, but... about that 36 volts. Speaking from experience, virtually everyone I have ever seen on this forum start with a 36v system has been happy enough for a while, and then decided they wished they had a bit more power/speed/utility. 36V regret is a real thing. Starting with a 48V battery is a good way to avoid regrets of not starting with enough power. For the same watt hour capacity, you don't really pay more for a 48V system compared to a 36V, but you have unlocked more of the motor's potential. You don't have to use the extra power or speed if you don't want it. The amount of power the motor puts out is literately in your hands. The throttle. You don't want to go so fast, turn the throttle less. A 48V 11.5Ah is roughly the same capacity battery as a 36V 15Ah. Just something to think about.
It's easier to have more power but not use it than it is to not have more power, need it, and have to buy a new battery to get it.

 

[dogman dan]

The Dillinger kit looks like a 48v kit, so yeah, it will be faster. Its one of the 500w rated motors I was talking about, but in 48v, the kits able to produce 1000w. No problem for that motor to handle 2000w, for as long as any battery would last. At 500w, it won't overheat indefinitely unless very overloaded.


But in the display you will have choices of assist levels, that are not specifically speed limiters, but do work in that way, so your battery goes farther and your speed is limited by the lower assist levels. The very lowest assist levels are nearly no assist at all, so you can find one that matches your needs.


But come a really big hill, or you tow a really big load, you can call up max assist while still rolling. So that kit is not a bad idea at all. Cruising on the flat at 15 mph, you will only need about 300w or less. But at times, that extra speed and or power is what you want, up that hill into 30 mph wind for example.

 

[la838]

Thanks both of you for your detail replies! I think I'll go with the Mac motor. The only thing I'm worried about now is the lack of a Torque Arm. Since I'm have a xtracycle leap I won't be able to get a torque arm for it. So I'm just not sure if is better to get a lower motor wind (8T?) so there's less torque? Or should I just get 10T and modulate my throttle control when taking off? 12T just sounds too intense, especially on a 20inch.