Advice on motor/conversion kit for first timer.

[Tarwinia]

Hi to everyone here,

So I am hoping for some advice on my first electric bike (conversion).

So I mostly travel on level ground but there are two hills, either of which I encounter regularly. One of them is short but steep, easily over 20º (I'd say about 35 to 40). The other is about 20º but long (about three quarters of a kilometer). So from what I understand a mid-drive might be better (also due to my weight).

So the requirements.

I live in Mexico right now and plan on moving to Toronto, ON, Canada (and I am thinking of taking the motor even if the whole bike isn't worth the bother). This means that I need a max speed of 32km/h using the motor (I can pedal faster but that's beside the point). It also means that according to Canadian law I need a max of 500w for the motor.
I personally weight about 230lbs.

I've looked at Lingbei, Tongsheng and Bafang but there was just so much information. But from what I udnerstand Tongsheng is good but not guaranteed to last, Lingbei seems to be way overpowered (32km/h on PAS1) so maybe Bafang BBS02 might be a good choice but I am completely open to any other suggestions or observations.

My plan is to use the bike as a scooter (for when I am exhausted or need to avoid being all sweaty when I get to work), PAS for when the weather will permit me some exercise without massive sweating, and as a regular bike with the motor off when I feel like getting some exercise/having fun.

The range would ideally be 20km or more but then again that depends on what battery I get (I'll most likely source one locally to avoid import problems).


Summary

Power: max 500w
Speed: max 32KM/h (20m/h)
Weight: 230lbs (240 with backpack)
Range: minimum 10, ideally 20 or more
Cost: w/o battery, $600 US


Thanks for any help/advice you can give me.

Btw, if there is a specific place for asking for this type of advice I couldn't find it and will gladly be redirected if there is.

 

[ngant17]

I got into my first e-bike with Bafang BBS-02. Very happy with long term(+ 1yr.) Bafang use so far. So much depends on your mechanical inclinations, abilities and available resources.

The e-bike "gas tank" is your amp-hours. Someone can correct me if I'm wrong, but 750watts by itself doesn't reveal much unless you know the voltage first. Wattage is power but that doesn't really tell me how far I can go, just by using watts. I know most everyone uses watts as the metric (voltage x amp-hours), but it makes more sense to me to reference batteries with rated amp-hours because that tells me how far I can go on my e-bike.

Everyone has their own philosophy wrt batteries and packs. Rule of thumb that I go by: “…raise the volts, lower the amps…”. So for my ride, I prefer higher voltages/lower amps, but I want more amp-hours to insure a complete roundtrip with power assist.

Biggest issue for me was and always will be quality of batteries and price.

 

[Dauntless]

My first advice is that if you want to spend less than what the minimum bike would cost, wait until you can afford the minimum bike. My first conversion was the 450w Currie kit, didn't make for much of a bike even if it worked fine for what it was. Me weighing considerably less than you at the time.

So I live near the same hill that was the big 'Prove you're a MAN' climb when was a kid. It's how I come home if I go downtown on a bike. 1000w may not entirely make it on its' own, but the pedaling is easy enough compared to some of the lame things I've fixed or built. I call that a starting point in your thinking. https://www.yescomusa.com/products/26in-rear-electric-bicycle-motor-conversion-kit-48v-1000w

 

[Chalo]

So I mostly travel on level ground but there are two hills, either of which I encounter regularly. One of them is short but steep, easily over 20º (I'd say about 35 to 40).

No. 20 degrees is 36.4 percent grade, which is on a par with the steepest paved roads in the world. A 20% grade is phenomenally steep by most people's reckoning, and that's a little over 11 degrees.

 

[markz]

So I mostly travel on level ground but there are two hills, either of which I encounter regularly. One of them is short but steep, easily over 20º (I'd say about 35 to 40).

No. 20 degrees is 36.4 percent grade, which is on a par with the steepest paved roads in the world. A 20% grade is phenomenally steep by most people's reckoning, and that's a little over 11 degrees.

You are right on that, just last night there were some lycra's on GCN yt wanting to climb some stretch rated as the steepest in the world, 34% for a few feet around a bend, I believe they were in NZ. Its funny because the pair were competetive and one rode up with a ebike assist using Strava, then the ending of the video, a world class lycra did his thing and the editor cut the vid as he passed the start line and some witty comment about a famous lycra.

 

[dogman dan]

20% is plausible for sure, he likely confused percent with degrees. My very strongest e bike climbed up to 20 degrees on 3000w, which is steep enough to be hard to just walk on. On a ski slope, above 20 degrees rates black diamond.


There is a paved state highway in New Mexico with an 18 % grade, but steeper is not uncommon on city streets, driveways, etc.


Get a kit with 750w, running on 36v for Canada. This could be a cheap hub motor 1000w 48v kit now, then replace the controller to run 36v later. 48v should get you up the hill ok, if it is less than a mile long. You'll still pedal hard, but make it.


You might like a mid drive better, but if the hills are short, a hub motor will get you up them at 15-20 kph, while pedaling hard. The main benefit of a rear hub motor is simple to install, and cheap cost. Not a bad way to go. In fact, cheap enough to sell it off when you go to Canada, if that is not too soon. You won't be able to take the battery unless you go by land travel. So maybe go cheap as possible now, so you can upgrade a battery later when you move.

 

[donn]

The e-bike "gas tank" is your amp-hours. Someone can correct me if I'm wrong, but 750watts by itself doesn't reveal much unless you know the voltage first. Wattage is power but that doesn't really tell me how far I can go, just by using watts. I know most everyone uses watts as the metric (voltage x amp-hours), but it makes more sense to me to reference batteries with rated amp-hours because that tells me how far I can go on my e-bike.

Everyone has their own philosophy wrt batteries and packs. Rule of thumb that I go by: “…raise the volts, lower the amps…”. So for my ride, I prefer higher voltages/lower amps, but I want more amp-hours to insure a complete roundtrip with power assist.

Biggest issue for me was and always will be quality of batteries and price.

OK, per your request, that first paragraph didn't come out quite right. Watts are Volts x Amperes, not Amp-Hours. Amp-hours actually have the same problem you mention - as a rating of how far you can go, they're missing the important Voltage factor. I have a 12V 7Ah battery around somewhere, useless little thing that wouldn't get you out of the parking lot - it's 7 hours of not much power. We normally don't care, because we're comparing batteries of the same voltage, but the complete storage measure would be Watt-Hours.

Back to Watts, the reality is that some things (like maintaining an efficient motor speed while climbing) need power (W), others (law enforcement) need to have the right sticker on the box. Manufacturers seem to have various ways to approach that disconnect, but it would be sweet if we had two different Ws - like Wp = power available for sustained use , Wl = legal power rating.

 

[Tarwinia]

Thanks for the advice everyone. Yeah, the voltage vs. amp hours makes sense so I finally decided on a 48v version of the motor.

The comments of 750watts or 1000 (or even 3000) are kind of pointless as that would make my e-bike stop being a bike under Canadian law (if it has a motor more powerful than 500 watts, can go faster than 32km/h, or a few other things it is considered a scooter/moped type vehicle and requires a license and to follow those laws and cannot be treated as a bike).

And sorry for confusing degrees with percentage

I have just ordered the battery (48v 14ah) and will order the motor tomorrow morning after checking one thing with my mechanic (basically to double check that he has the tools necessary as I have seen comments from people saying they were missing the right tool for tightening the motor, which is basically a lock nut wrench).

Thanks again everybody!

 

[Chalo]

If you need to climb steep grades, 500W will not help you enough. My advice is to ignore the power limit and observe the speed limit. Use 1000W+ that tops out at no more than 32kph, and you'll have plenty of climbing torque. Use a lower power system with insufficient torque to climb your hills, and you'll cook it. (Correctly geared mid drives excepted.).

If the bike doesn't go faster than 32 klicks, what could there be to distinguish it from a fully compliant e-bike? (Besides being able to climb your hill without burning down?)

 

[dogman dan]

To clarify, you could get a 48v 1000w kit, which actually comes with a 500w rated motor. That motor can run on up to 2000w, depending on the load, duration of the run, etc. The kit comes with usually a 20 or 30 amps 48v controller, which yields a 1000 to 1500w maximum at start up, then drops to about 1000w at full speed.


Once you get to Canada, you can replace the controller with a 500w limited version. 36v 15 amps, or cheat a bit to 750w max, using a 36v 20 amps controller. They you are Canada legal. With a 36v 20 amps- (750w) controller, you'd still be legal enough at full speed, since then amps drop, and the wattage is around 400-600w, at 20 mph.


If you won't be in Mexico long, get a cheap 48v lead battery to start. Then when in Canada, you replace it with a lithium 36v. You can't fly with a large lithium battery, at all. So get Canada legal when you get there, with a new battery and controller then.

 

[ngant17]

The e-bike "gas tank" is your amp-hours. Someone can correct me if I'm wrong, but 750watts by itself doesn't reveal much unless you know the voltage first. Wattage is power but that doesn't really tell me how far I can go, just by using watts. I know most everyone uses watts as the metric (voltage x amp-hours), but it makes more sense to me to reference batteries with rated amp-hours because that tells me how far I can go on my e-bike.

Everyone has their own philosophy wrt batteries and packs. Rule of thumb that I go by: “…raise the volts, lower the amps…”. So for my ride, I prefer higher voltages/lower amps, but I want more amp-hours to insure a complete roundtrip with power assist.

Biggest issue for me was and always will be quality of batteries and price.

OK, per your request, that first paragraph didn't come out quite right. Watts are Volts x Amperes, not Amp-Hours. Amp-hours actually have the same problem you mention - as a rating of how far you can go, they're missing the important Voltage factor. I have a 12V 7Ah battery around somewhere, useless little thing that wouldn't get you out of the parking lot - it's 7 hours of not much power. We normally don't care, because we're comparing batteries of the same voltage, but the complete storage measure would be Watt-Hours.

Back to Watts, the reality is that some things (like maintaining an efficient motor speed while climbing) need power (W), others (law enforcement) need to have the right sticker on the box. Manufacturers seem to have various ways to approach that disconnect, but it would be sweet if we had two different Ws - like Wp = power available for sustained use , Wl = legal power rating.

Thanks for the correction. Amp-hours x voltage is watt-hours, which is the standard measurement on your house's utility electric meter (kilowatt hours, actually). However in my experience everything really revolves around voltage or potential energy. Voltage is the energy available to do work, which is like water pressure that's contained inside a water pipe. You're not going to take a shower very well with a trickle of low water pressure. Likewise you're not going to have much effect on an e-bike with low voltage.

So your 12v x 72Ah is a 864 watt-hours. Seems like a lot to me. OTOH my 60v 4aH battery is 240 watt-hours. That is not a puny battery at all. It can instantly take off like a rocket and still maintain enough stamina to go quite a few kilometers based on gearing of bike.

 

[Chalo]

I have a 12V 7Ah battery around somewhere, useless little thing that wouldn't get you out of the parking lot - it's 7 hours of not much power.

So your 12v x 72Ah is a 864 watt-hours. Seems like a lot to me. OTOH my 60v 4aH battery is 240 watt-hours. That is not a puny battery at all.

He said 7Ah, not 72Ah. He's probably taking about one of these little sealed lead-acid batteries:

Those have a rated capacity of 84Wh, but you'd better not use much more than half of that if you need them to last.

 

[markz]

For lead acid, you take whatever the Amp-Hour (Ah) rating is, and you slice off 40%, that is your actual capacity for lead acid. Its something ridiculous like that. Plus you may pay less, but they wont last near enough time. Lead Acid is old technology for ancient and out-dated ebikes. Spend the extra bit and go Lithium Ion, whether it be Power Tool batteries (new or used), Li-Ion, LiPo, then there is LiFePO4 which is 50/50 because it takes up so much space for what you get.

https://www.pvcdrom.pveducation.org/BATTERY/charlead.htm

Battery Efficiency

Lead acid batteries typically have coulombic efficiencies of 85% and energy efficiencies in the order of 70%.

 

[donn]

It should be clear that no one's recommending a lead/acid battery for a bicycle motor. But LiFePO4, yeah! If I ever need to buy another battery, it's going to be another LiFePO4. Seems like the cautions about lithium batteries come with an "except LiFePO4" clause. Let the charger run to 100%? No problem with battery life - if it's LiFePO4. Worried about it bursting into flames? Guess it isn't LiFePO4. Made with cobalt from central Africa where the Chinese are sewing up the supply by making deals with corrupt governments? Not LiFePO4, that's "Lithium ion" which really means Lithium Nickel Cobalt.