Downtube Folding bikes: Help picking a front hub motor & battery

General Discussion about electric bicycles.
Post Reply
downtube   100 µW

100 µW
Posts: 9
Joined: Dec 17 2015 2:39pm
Contact:

Downtube Folding bikes: Help picking a front hub motor & battery

Post by downtube » Nov 24 2018 11:53am

Hi everyone! I design Downtube folding bikes. We have decided to add a front hub electric conversion option. Let me explain my thinking on using a front hub motor.
1. Folding bikes are normally rear heavy. Hence they can pop wheelies on steep climbs. Putting more weight up front will help with weight distribution... making it safer.
2. Small bikes need to stay light & portable. So we are looking for a small battery solution. Riders can always choose to bring multiple battery packs.
3. Ideally we would like to customize bikes for customers. We would do the swap pre-purchase. To scale the business this needs to be easy to install.
4. We only use 20" & 16" wheels. So the solution must work with our current offering.

I envision us going with rear hub & mid drive motors in the future. However I want to keep it simple for now.

Thanks
Yan
Designer of Downtube Folding Bike
Ph.D. Temple University ( Math )
Biked across the USA twice
Semi-active chess player ( two time Bahamas National Champion )
Sivananda ( Bahamas ) Trained Yoga instructor ( 2013 ) and ThetaHealer since 2013

docw009   100 kW

100 kW
Posts: 1081
Joined: Aug 02 2015 7:43am
Location: Chicago area suburbs.

Re: Downtube Folding bikes: Help picking a front hub motor & battery

Post by docw009 » Nov 25 2018 1:04pm

I've put the Q100H motor on the rear wheels on two of your folders, Nova and FS8. WIth 36V, they run around 18 mph, which matches the cadence for a 46T front and 11T rear gear, if pedal assist is being used. I believe They'll go about 20-22 mph on 48V and around 24 mph on 52V. I've also put a Q100H on a 20" minivello on the front wheel. I use 20A sinewave controllers.

For a commercial product, I would suggest looking for a controller with waterproof connectors and an integrated main cable. Something like this one that I got from CNEBikes. Only the PAS connector is clunky.
P1080378.jpg
P1080378.jpg (73.7 KiB) Viewed 319 times
Otherwise, most DIY controllers look like this. A terrible rats nest. I end up splicing in a modular connector for the motor, and sometimes combine all the handlebar wires into a single cable. Looks nicer, but shrink wrapped solder isn't that reliable.
P1040280.jpg
P1040280.jpg (99.56 KiB) Viewed 319 times
It's hard to stow a battery on a folder. I put a 30cell 36V9AH unit on my wife's bike under the seat. It's good for over 30 miles at 13 mph. I use a 20 cell 36V4AH under the seat on mine, good for 12 miles, but I will carry a spare. We rarely ride more than 15 miles at hone anyway. The trouble with these are that both are shrink wrapped batteries with little protection.

Here's my Nova with single battery in seat bag. Controller mounted under rack.
P1600763-2.jpg
P1600763-2.jpg (110.82 KiB) Viewed 319 times
Here's my minvello with a smaller 30 cell bottle battery on the frame. 36V9AH. These don't fit your bikes unless someone were to move the bottle mount rivets or change the mount to be up front. The mount wasn't too durable anyway. I had to add a second one. I'm also unhappy with the battery capacity on this model from unitpackpower. It seems to self discharge fast. Works OK if I charge it before a ride.
P1650152.jpg
P1650152.jpg (147.13 KiB) Viewed 319 times

downtube   100 µW

100 µW
Posts: 9
Joined: Dec 17 2015 2:39pm
Contact:

Re: Downtube Folding bikes: Help picking a front hub motor & battery

Post by downtube » Dec 02 2018 11:28am

Thank you very much for your feedback & insight. Might you have a few brands of front wheel motors that are easily available and quick to install?

I found Geo Orbital, https://www.geoo.com . This would be an easy aftermarket install for us to modify new bikes before shipping to customers. This way we can sell e-bikes and bikes with minor changes before shipping. Unfortunately, Geo Orbital don't make 20" wheel models.

Thanks,
Yan
Designer of Downtube Folding Bike
Ph.D. Temple University ( Math )
Biked across the USA twice
Semi-active chess player ( two time Bahamas National Champion )
Sivananda ( Bahamas ) Trained Yoga instructor ( 2013 ) and ThetaHealer since 2013

chvidgov.bc.ca   10 kW

10 kW
Posts: 813
Joined: Apr 24 2008 4:52pm
Location: Victoria, British Columbia

Re: Downtube Folding bikes: Help picking a front hub motor & battery

Post by chvidgov.bc.ca » Dec 02 2018 5:18pm

Check out this page...small front hub motor...I think it would work well on the Downtube, with nice balance with a battery on the back rack. Grin is lovely to work with and they are probably the most knowledgeable folks around when it comes to small hub motor solutions for a variety of bikes. I have electrified Raleigh 20, Cannondale Hooligan, Bridgestone Sneaker and other cool small bikes with parts from Grin, mostly sticking to simple front motor configurations which I tend to prefer on folding bikes for simplicity as well. That minivelo of yours is a neat looking bike btw.

https://www.ebikes.ca/shop/electric-bic ... laced.html

mark5   100 kW

100 kW
Posts: 1253
Joined: Dec 28 2011 9:26pm
Location: USA

Re: Downtube Folding bikes: Help picking a front hub motor & battery

Post by mark5 » Dec 02 2018 6:06pm

downtube wrote:
Dec 02 2018 11:28am
I found Geo Orbital, https:// www. geoo.com . This would be an easy aftermarket install for us to modify new bikes before shipping to customers. This way we can sell e-bikes and bikes with minor changes before shipping. Unfortunately, Geo Orbital don't make 20" wheel models.
I like the Onemotor (https:// onemotor.co) instead as an all in one friction drive.

Bmsbattery have spammed here before about their all in one wheel (https:// bmsbattery.com/motor/857-all-in-one-hub.html). It's available in 16" & 20".

Apparently, Yunzhilun iMortor has a 20" all in one wheel now:
http:// m.imortor.com/imortor/20-inch-folding-bicycle-imortor-front-wheel.html
https:// www. aliexpress.com/item/iMortor-Electric-Motor-Wheel-Electric-Bike-Conversion-Kit-with-Battery-All-in-one-Eelectric-Bicycle-Motor/1000004921734.html
On the iMortor you can at least bypass the built-in battery & controller after they fail and use proper external components. Don't know whether you can with the Bmsbattery.

Post Reply