Help on first build

[spicyhappy]

Hello! I'm planning out my first ebike build. I figure it will be way more fun and a greener way to get around. Really appreciate any help and advice since I'm a complete ebike noob.

I have an used Yuba Mundo Classic V4 cargo bike (steel frame + fork) in good condition. Here are some initial requirements:

- Be able to carry 2 people + 2 kids + groceries (~450 lbs)
- Range of 20 miles with pedaling
- Doesn't need to accelerate fast or go faster than 20mph (but if does that would be fun)
- My roads are nice with medium sized hills (nothing too crazy)
- Would be nice to be able to ride through light rain and snow
- Budget under $1.2k ish

I'd like to keep it easy to build and maintain. I can do basic bike maintenance and solder but building a battery pack from scratch sounds very intimidating. So many of the builds on this site are way beyond my current skills hahaha.

It seems like a front wheel hub motor is my best choice. What do you think about these these ebike kit options? The ones on Amazon seem to be quite a bit cheaper though I'm not sure about the quality.

- E-BikeKit heavy duty front wheel with battery: https://www.ebikekit.com/collections/heavy-duty-systems-lithium/products/e-bikekit-heavy-duty-front-lithium-48v
- Grin all-axle ready-to-roll kit with battery: https://ebikes.ca/product-info/grin-products/all-axle-hub-motor.html)
- eZee front kit: https://ebikes.ca/shop/electric-bicycle-kits/ezee/ezee-front-kit-advanced-pas.html)
- Magic Pic Edge Vector 26" front conversion kit: https://goldenmotor.bike/product/magic-pie-edge-vector-26-inch-front-conversion-kit/)
- AW 26" 48V 1000w: https://www.amazon.com/AW-Electric-Bicycle-Powerful-Conversion/dp/B00YBWA5VC)
- EBikeling 26" 48V 1200w: https://www.amazon.com/EBIKELING-Waterproof-Electric-Bicycle-Conversion/dp/B07MY98WX6)
- Voilamart 26" 48V 1000w: https://www.amazon.com/Voilamart-Electric-Conversion-Intelligent-Controller/dp/B07Q7FJ8ZY)

Thanks for your help! I'm excited to pick something and get started.

 

[markz]

What is riding terrain like, do you have large steep long hills or is it flat?
Will there be a lot of stop and go like your downtown or something.

 

[spicyhappy]

We live in the suburbs and the roads are really smooth and well maintained. No crazy hills but some medium sized ones I have to huff and puff to get up. Potentially a bit of stop and go if we go to the town center and mall area.

 

[anddan]

Hi, ok so if you don't already know theirs a great motor simulator from GRIN technologies at

https://ebikes.ca/tools/simulator.html?mass=170&throt=100&grade=0

450lbs is heavy so you'll need a very torquey setup. The black line is the load line and the red line is the power line. With the throttle at 100% where the load line and the power line intersect will be the top speed. If your in a hilly area you'll need to input the grade of the hills that your expecting to climb, so long as the black line is below the red line you can climb the hill however slowly. You'll need a larger motor because the main danger with a high power setup is that the motor will overheat and melt the windings. First question would be what is the size of the dropouts. That will limit the upper end of what you can fit in the forks. As an example, the crystalyte 3540 motor that I have on my bike, just barely fits in the standard rear dropouts. You can play with the motor simulator a little bit. You mentioned the grin all axle motor, they list three on their website and I don't know which is the right one that comes with the kit. You can see though that Grin V2 STD you would be able to reach 40 kmh with a 36v battery and and a 20a amp controller. So theirs a nice little table that shows you the motor won't overheat in those conditions. At a five percent grade it would overheat in 5 minutes at full throttle. I hope this makes some sense to you. I'd like to help you more. I recommend reading the GRIN pages, if you don't understand something I can try to help. Peace.

Andrew

 

[goatman]

first ebike kit is, $1700 w/20ah battery out of stock til nov.20.2020
grin all axle, $1200 with ca and phaserunner, still need a battery, but high quality, phaserunner is waterproof/reliable can handle winter

https://endless-sphere.com/forums/viewtopic.php?f=6&t=103834&p=1563109&hilit=scorpion#p1521378


id go with the grin technologies just to get the cycle analyst and phaserunner, you can connect any battery or motor to them

 

[markz]

This is a great feature to use, plug in your route into the Google Maps feature.

https://ebikes.ca/tools/trip-simulator.html

 

[Balmorhea]

I have an used Yuba Mundo Classic V4 cargo bike (steel frame + fork) in good condition. Here are some initial requirements:

- Be able to carry 2 people + 2 kids + groceries (~450 lbs)
- Range of 20 miles with pedaling
- Doesn't need to accelerate fast or go faster than 20mph (but if does that would be fun)
- My roads are nice with medium sized hills (nothing too crazy)
- Would be nice to be able to ride through light rain and snow
- Budget under $1.2k ish

Because you have a different than normal performance profile, it's a good idea for you to get a motor with a lower than normal RPM per volt. With most hub motors, you don't have a choice, or maybe you have a couple to choose from.

Leaf Bike offers affordable hub motor kits with custom RPM per volt by request at no extra charge. I have a front wheel 1500W version on one of my bikes, and it's very good. I ride it regularly with a gross weight of about 450 pounds.

https://leafbike.com/products/diy-bike-conversion-kit/26-inch-48v-52v-1500w-front-hub-motor-bike-conversion-kit-1073.html

You can tell Leaf what top speed you want, and they'll give you the appropriate version. The lower the top speed, the harder it will take off from a stop, and the steeper a grade it will climb with the same controller and battery. So there's a benefit to getting a motor that goes only as fast as you want, but not faster. If you don't specify when you buy, they'll give you a version that wants to go about 40mph, and won't perform very well at the speeds you actually ride.

You will need good secure torque arms to do what you're planning with a front hub motor. I don't think the Leaf kit comes with any. So read up on that topic.

 

[dogman dan]

So, thats a lot of load. Not particularly a problem, till you run up a steep hill, or worse, a long steep hill. So how much hills you have to deal with means a lot. If you live in mountains, you may have a problem with that much weight. But if you live on a flat coastline, the steepest bridge will not be a problem.

I used to work for E bikekit, first as a product tester, basically trying to kill the kits overloading them, then on line with customer service. Retired now. The one big virtue of the EBK heavy duty kit, is that its a slower wind motor. Lots of arguments about is slow better, but when you weigh 450 pounds, it kind of goes without saying that you won't be going fast, especially up a hill.

Yep, its a pricy choice, and still really should not be loaded past about 400 pounds ( meaning the bike and battery too) if you climb a longer hill. Too steep and too long with a hub motor can mean a lot of heat generated, because you cannot do that combination of high weight load, and high slope load for too long without getting the motor very hot. BTW, I never was actually able to melt one of those heavy duty motors, but I never tested past 400 pounds load either. We just wanted to know if we could sell the thing to a 300 pound guy. The main thing here is that if you ride overloaded, and then ride up hills overloading it more, the very least thing is that your use of the battery becomes spectacularly inefficient. You basically spend your battery making the motor hot.

But the BEST solution to overloaded cargo bikes without getting inefficient, is to slow waaaaaay down, using a mid drive and low gearing on the bike. With this approach, you spin the motor fast, efficiently using higher rpm the motor likes. But your actual speed will be no faster than your lowest gear can go.

Lastly, another approach works really good. Huge rear hub motor, mounted with a 20" rim, and throw about 2000w or more at it. Top speed unloaded can be 30 or even 35 mph. But the huge motor will not stall on the hill, and ride up it at 15 mph with excellent efficiency. Rpm is fine, and you get to the top quicker, but the downside is you need to invest in batteries able to dish out 2000w or more, which gets expensive.

I vote for the mid drive kit if you have mountains, or at least very steep rolling hills, and the E bike kit slow motor if your ride only has mild hills, like less than 5% typically. The hub motor kit will only struggle when you have her on the back, and the kids in a trailer. By yourself, it will do great on a grocery run. You might not really need all that much for the rides you do 90% of the time, one person, going to get the grub.

The lower rpm leaf kit would work well too, and is less costly. Similar motor to the EBK kit in capability. The EBK kit has a more water resistant controller and wiring harness, if you live in a really wet place. Easy to just mount the controller and plugs of the leaf kit in a dry spot, on a yuba, like under the deck, but above the fender.

 

[spicyhappy]

Thanks for the advice! I feel I learned so much from your informative posts. I didn't know about how heavy loads affect the motor, that's really good to know.

I think I will look into the e-bikekit heavy duty kit and the leaf kit. It's reassuring to know that these two can lug super heavy loads. Most likely we probably won't be fully loaded all the time. By the time the kids weigh a lot maybe it's time to get them their own ebikes hahaha.

@bakmorhea: What top speed did you ask leaf for if you don't mind me asking? And which battery did you purchase with it? There are so many options out there and I'm not sure how to pick the best one.

@markz : I went into Google maps to look at the hills in my neighborhood, and probably the steepest hills I would need to tackle is about 5% grade. It is a really handy feature! I never thought to use it this way.

@anddan : I measured my dropout for my front fork. It looks like it's a standard 100m wide, the slot is open and ~11.5mm. Should be good for the front hub motors I checked out!

I also looked at the stats for on the ebikes calculator and it looks like for the grin system, I would be able to go 5.2 mph up the steeps hill when the bike is fully loaded and over heat in 5 mins. The graph is pretty nuts though, I'm not sure I did this right. I wasn't able to figure out how to put in the ebikekit and leaf bike systems in there for a comparison though. The terms sound like a foreign language hahaha.

 

[markz]

Leaf 1.5kw is close to default motor Crystalyte-H at least in terms of physical size but will be off on internals like lamination thickness.

No, dont go look at Google maps itself, go to the link I provided and use their Google Maps to input the route you will be taking, then input a motor and controller and weight and see what the graphs say.


https://ebikes.ca/tools/trip-simulator.html
Top of graph is a pull down menu
Manual Plot to Google Maps, click ok
Though I see the migration of their website it is currently down.
A Google Map should come up, and you right click your starting point, then right click your end point, automatic route is given and you can move that line to the route you take. Left side is all the other inputs.


Try it again in a day or 2, its a very neat feature Justin installed on his website.

Thanks for your patience everyone during this website migration. Order checkout is now fully enabled!
There are clearly many visual glitches with the layout and the image and video embedding that we are working to iron out.

 

[Balmorhea]

What top speed did you ask leaf for if you don't mind me asking? And which battery did you purchase with it? There are so many options out there and I'm not sure how to pick the best one.

I asked for the 6 turn winding, 418 unloaded RPM, with the intention of getting about 23 mph in a 20" wheel on a cargo bike. Plans changed, and now it's in a 29" wheel. So it tops out around 30 mph, and I have to use the controller's assist level settings to go the speed I intended. I plan to get an 8 turn (290 RPM) motor for the bike, but I haven't yet. 7 turn gives 355 RPM.

You can use this tool to calculate road speed:
https://www.4qd.co.uk/road-speed-calculator/
The "reduction gear ratio" of a hub motor is 1. Keep in mind that when the motor is pushing at top speed, it will only be turning about 80% of its unloaded speed, give or take.

I built my own battery packs from automotive cells. If I were to buy a ready to use pack from someone else, I reckon I'd start at EM3EV.

 

[anddan]

Hey Spicy

I think dogman is right that you'll need either a middrive motor that can make use of the gears, or a large hub motor. The H series motor that I have I run at 1400 watts continuously and it only overheats on a hot day and riding 30 minutes or so. Hopefully the leaf as markz says will have a similar amount of actual metal in it so it will withstand the heat. The nice thing with the middrive is the gearing. With a larger front chain ring and smaller rear chain ring you'll have higher speeds but need more power. With a larger rear chain ring and smaller front chain ring you'll have lower speeds and less power. The kit on the simulator the stokemonkey is no longer sold by grin. But theirs other kits like the bafang, https://ebikebc.com/product/mid-drive-kit-1000w/ which would from the looks of the stokemonkey curves deliver plenty of power. Another thing to consider is the battery life. Because your going to be running at 1000-2000 watts, the number of amps your drawing will be 2000watts/battery voltage for instance 2000/36V =55 amps. so a 20 ah batter would only give you about 25 minutes of operating time. You can do more than that but I think for the bottle mount batterys that is about the maximum. Some thoughts to consider.

Andrew

 

[Balmorhea]

I advise you not to use a mid drive, for a couple of reasons.

As a disclaimer, let me say that watt for watt, a mid drive kicks so much hub motor ass it’s not funny. And it’s way more entertaining to use, because there’s a technique to it. Like driving a stick versus an automatic.

But you should not do it. Here’s why.

All the power a mid drive produces goes through the bike’s gears. That wears things out fast and breaks them. It also means the electrical drive and the pedal drive are one and the same. So when things break out on the road, you’re stuck.

Hub motor drive means your chain drive is doing (at most) the work it used to do, and most likely less, as you lean on the motor to provide the bulk of the work. And it means when something goes wrong— either with the motor or with the chain drive— you have a backup method to get you back to base.

When reliability is a factor (such as when you have kids on board), the hub motor is much better at delivering that reliability. It has a more limited operational envelope, and attenuated performance compared to a mid drive, but it does its job more consistently, more of the time. That’s why I changed my commuter bike from Bafang BBS02 mid drive to front hub.

 

[spicyhappy]

Just wanted to follow and thank everyone for their generous help and advice! My family and I built the e-bike last November and have been riding it these past few months. I bought the heavy duty kit from E-BikeKit during their holiday sale. It only took a few hours to put together. If you're interested I put some photos and wrote about my process here: http://spicy-happy.com/diy-family-e-bike/