Help with an e-bike for my courier job

Chataylo

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Hi everyone, this is my very first post here. Great to be here!

So I'm a bicycle courier. I typically pedal my road bike 8-12 hours a day. I'm looking to change that this year. I want to convert one of my two spare bicycles into an e-bike. I have a mountain bike and a cruiser bike to choose from, both with study metal frames.

I want to go 15-20 mph for 10 hours. I'm wanting a 150-200 mile range. I realize this is a lot and I will probably have to wire several expensive batteries in parallel.

My neighbor has built two e-bikes in the last year and he got me interested. He's an engineer. I helped him build his last one so I get the general idea of what I'm doing.


____________________Needs__________________


Desired max speed on level ground: 15-20 mph
Desired max range: 150-200 miles. I want this bike to run 10 hours at that 15-20 mph.
Wheel size: 26" wheels.
Rider weight: 180 pounds
Terrain: 100% flat. Indianapolis metropolis.
Budget: I'd like to keep this under 1500$ but will go up to 2000$ if needed

So basically, my two biggest questions are voltage and amp requirements. Feel free to throw in any other thoughts you have.
 
Chataylo said:
Hi everyone, this is my very first post here. Great to be here!

So I'm a bicycle courier. I typically pedal my road bike 8-12 hours a day. I'm looking to change that this year. I want to convert one of my two spare bicycles into an e-bike. I have a mountain bike and a cruiser bike to choose from, both with study metal frames.

I want to go 25-30 mph for 10 hours. I'm wanting a 300 mile range. I realize this is a lot and I will probably have to wire several expensive batteries in parallel.

My neighbor has built two e-bikes in the last year and he got me interested. He's an engineer. I helped him build his last one so I get the general idea of what I'm doing.


____________________Needs__________________


Desired max speed on level ground: 25-30 mph
Desired max range: 300 miles. I want this bike to run 10 hours at that 25-30 mph.
Wheel size: 26" wheels.
Rider weight: 180 pounds
Terrain: 100% flat. Indianapolis metropolis.
Budget: I'd like to keep this under 1500$ but will go up to 2000$ if needed

So basically, my two biggest questions are voltage and amp requirements. Feel free to throw in any other thoughts you have.

Just doing the math for the laugh test. To maintain 30mph, you'll use around 40Wh/per mile. So, for 300 miles, that's 12,000Wh. If you go with a 52V pack, which is a common voltage and enough to get a lot of motors run at 30 mph, that would be a 52V 230Ah pack. If you use high energy cells, capable of 3.5Ah, you would need a 14S67P pack. You can probably fit 14S9P (126 cells) into a decent sized frame triangle, so you'll need a bit more space. 14S67P is 938 cells (and 105 lbs). Quality cells with 3.5Ah capacity cost around $5 each. That's $4690 for the cells alone, so may not fit into your budget.

https://ebikes.ca/tools/simulator.html?motor=MGRIN_STD_SA&batt=cust_52_0.2_230&hp=0&cont=C25&axis=mph&cont_b=C25&motor_b=MMAC6T&batt_b=cust_52_0.2_230&hp_b=0&bopen=true

If you lower your speed requirements, you can cut your battery capacity by a lot, or if you plan to pedal, you could add 100W-150W of human power to you assumptions and cut the capacity even more. Ebikes are pretty efficient at 20mph, but range decreases significantly above 20 mph due to wind resistance.
 
Thank you for slapping me into reality. :)

Jeez, I had no idea the battery cell requirements were so huge. I thought the approximate amount would be an order of magnitude lower. Okay. I'm adjusting my new speed target to 15-20 mph.
 
Chataylo said:
Thank you for slapping me into reality. :)

Jeez, I had no idea the battery cell requirements were so huge. I thought the approximate amount would be an order of magnitude lower. Okay. I'm adjusting my new speed target to 15-20 mph.

I'm assuming that would lower voltage, like 36 maybe?


You have the ideal situation for a long range ebike, since you have no hills to deal with. If you pedal, and keep your speeds down to normal/higher bicycling speeds, you can get a lot closer to your range requirements.

If your contribute 100W of pedal power (pretty normal), and keep your speed to 15mph, then you could do it with a 52V28Ah battery, which will fit into a normal bicycle triangle. You may want to go with a geared hub, since it will be like a normal bike if your battery runs out.

https://ebikes.ca/tools/simulator.html?motor=MGRIN2708&batt=cust_52_0.2_28&hp=100&cont=C25&axis=mph&cont_b=C25&motor_b=MG310_STD&batt_b=cust_52_0.2_28&hp_b=100&throt=49&bopen=true&throt_b=47

You can still go full throttle and hit your 25mph+ speed, but it will cut into your range.
 
Thank you for the calculator link. It was confusing at first... but after playing with it for a while it is answering a ton of my questions. Amazingly helpful.
 
The mileage that courriers are doing would require charging during the day, if you want some speed. I would build a PAS ebike using high C rate RC lipo that can charge in 15 minutes. The combination of efficiency and fast charging should make it good for the task.
 
Could look at something rugged prebuilt like a juiced ODK v3. Has an option for a long range battery pack and a 500-1000W bafang front hub.
 
Geared hub motors freewheel, while direct drive hub motors do not freewheel thats why they can do regen but when when you run out of battery power the hub motor drags and feels like you are riding with a flat tire, there is more resistance.

There is that one geared motor that is a little different. MAC is a geared hub motor but what if you want regen, enter GMAC. DD's are more durable then geared hubs because dd's have no moving internal parts.

GMAC motor
GMAC Clutchless Geared Hub Motor
https://ebikes.ca/gmac8t.html
https://ebikes.ca/product-info/grin-kits/gmac.html
Introduction

The GMAC hub motor is a collaboration between Grin and MAC motors to produce a unique hub motor in the electric bike space: a geared motor with powerful regenerative braking, integrated no-play torque arm, and near perfect bike frame compatibility. We started this co-development in earnest in late 2017 along with Bike Swift and after much testing and refinement are happy to indroduce this hub in our 2019 motor catalogue.

What's Special?

The core motor performance is the same as you would expect from the latest MAC motors. That includes a modern cassette freehub system instead of a screw on freewheel and a powerful 20mm wide stator core made with thin 0.35mm laminations, but the following differences make it really stand out

Locked Clutch:

Clutchless Planet CarrierIt's been the norm that geared hub motors have a built in freewheeling clutch so that the motor coasts in the forwards direction with no drag, but this prevents regenerative braking, reverse operation, and the clutch itself becomes a common point of failure with high torque motors. The GMAC motor does away with the freewheeling clutch entirely, allowing powerful and efficienct regenerative braking and one less component to fail.
 
BTW, something that likely hasn't been taken into account is that you are very likely riding in city traffic, and having to stop and start a *lot*. This can greatly increase your Wh/mile, especially if you are carrying any significant weight, and as the bike and rider weight go up. You may be able to see some of this using the Trip Simulator that is linked from the Motor Simulator you're already trying out, if it will let you setup a bunch of stops and starts (probably hundreds of them in 10 hours of riding).


As an example, my CrazyBike2 (which was around 400lbs total including me and the bike and the motors and battery), with a cruising speed of 20mph and an average of probably 13-14mph in city traffic, would get something around 30wh/mile. But if I rode along streets with almost no stops for the same kind of distance (a few miles), I could get down around 22wh/mile, still crusiing at 20mph, with an average closer to 15-16mph or more. So even though the average speed was higher on the less-stops trip, which increases the aerodynamic losses and power usage, it was still less power usage than having to stop and start up to a few dozen times in the same kind of distance.

That example is all just the motors, without pedalling (pedalling will make a difference but depends on you, your gearing, your energy and capability and willingness, etc).

The difference will be less the lighter the bike is (and the more you are pedalling to startup from the stop, vs letting the motor do it)....
 
In my experience 20-30 whr/mi at 20mph is a good benchmark for many ebikes with no pedaling. Even my old brushed-motor mid-drive build used around 30 whr/mi. The simulator will tell you better though.

I think you may want to reconsider your needed range too. Do you really ride 150 miles in a day? Let's say you ride at 15mph on average for 10 hours. Then yeah you would, but that doesn't include time to lock up, run packages in, etc. If we take off about 15% for those sorts of things, you're now riding 8.5 hours at 15mph, now needing only around 130 miles of range. At 30whr/mi, that's about a 4kwhr pack. Now I'm seeing 52v 30ah packs on ebay for about $500 each. That's about 1500 whr per battery pack, so you'd need 3 if you carried them all at once. They are about 8.5 kilos each, so you'd be carrying a total of 25.5 kilos of battery, or around 56lbs. The weight adds up fast. Even at 20 whr/mi you're still going to need 3000 whr of battery.

An alternative may be to have a few 20Ah hailong batteries available for swap out. If you have an office, or apartment you could stop-off and switch batteries When needed and easily achieve your 150 miles of range. Another adder would be charging on breaks or lunch, etc with a high-amperage charger... again assuming you'd have access to an outlet. With a 5 amp charger you could put 150 whr back into the battery. That's not a ton of range though... 7.5 miles.

Don't know if that helps, but I've done the latter of the two options above before. Go to work, plug 'er in all day, go home.
 
Have a half dozen beefy packs ready to go, carry one extra and swap them out two at a time every 2-3 hours of your shift.

The charging station needs to run at 0.6 - 0.8C

Since unattended, go LFP rather than the higher voltage fire-risky 3.6 - 3.7V chemistries.

Lower density but much safer.

Prepare to spend more on the batteries + chargers than you'd want to spend on the rest of your hardware.
 
Charging LiPo at 4C is **really** asking for trouble, many orders of magnitude more likely to hit thermal runaway than slower rates OR normal li-ion

which in turn much riskier than LFP.

Go slow and safe, and swap the packs out. Bigger investment but not only safer but lasting 10 - 20x longer, works out to **much** cheaper cost per month
 
To use E-HP's simulations to illustrate MadRhino's point, assume 52V28Ah 1.3kWh battery is 14lbm (6.4kg = 200Wh/kg), and assume a 300W waterproof bulk charger that weighs 1.5kg = 200W/kg. Bringing the charger is equivalent in weight to 300Wh of battery. Conveniently, the 300W charger, charging for 1 hour = 300Wh, is equivalent to the weight of the extra battery. So with this charger, if you can charge for at least an hour, bringing the charger is more weight-efficient.

E-HP said:
Just doing the math for the laugh test. To maintain 30mph, you'll use around 40Wh/per mile. So, for 300 miles, that's 12,000Wh.
Bringing the charger (instead of 1.5kg more battery) costs you 7.5 miles = 15 minutes riding.

E-HP said:
If your contribute 100W of pedal power (pretty normal), and keep your speed to 15mph, then you could do it with a 52V28Ah battery, which will fit into a normal bicycle triangle.
Bringing the charger (instead of 1.5kg more battery) costs you 54 miles = 3.5 hours riding.


I don't think I would design around an arbitrary speed.
1) Do you make more the faster you go?
2) Can you recharge at some point during work? If so, how much?
 
Chataylo said:
I want to go 15-20 mph for 10 hours. I'm wanting a 150-200 mile range.

As others have said... naw.

Instead plan on having multiple packs that you can rotate out, running one while others are charging. This is how festival pedicabbers get the endurance you're looking for. You can probably reduce your total battery requirement by something like two-thirds if you rotate three or more packs. And your rig will be much lighter and more pleasant to ride.
 
Carrying a charger is not likely to be relevant here, having to go unavailable not an option

swap and go is required, biggest challenge is locating the charge station with charged spare packs.

Especially if not living right in the city center.

Another option might be a small petrol motor conversion, infinitely higher energy density, refill stations everywhere without waiting, much cheaper investment.

Heretical here I know, some might even say evil [emoji83]
 
Yeah, swap and go, combined with some kind of home base where you can have several batteries on a relatively fast charger.

I'm going to go out on a limb here, and say go with RC lipo. Yes, its dangerous, so your charger needs an outside, fireproof place, like inside an old barbeque grill. RC lipo packs can be a bit cheaper, so you can afford a few more of them. But more importantly, they can be charged faster than some other types of cells.

And you might go with something in a combination. Some of your packs could charge slower, if only one cycle a day was expected from them. So you'd start out with fast charging packs, then switch to the slower stuff mid day, then pick up the fast charge packs to finish the day.

Lastly, its likely the cruiser can be adapted best to carry more of the battery at a time. Its frame will be nice and stiff. But to really carry a lot of battery, you are looking at building a custom frame that is very very stiff, and able to carry a lot of weight without wobble. I wanted long range at one time for different reasons, and used only the front half of a good steel mtb to build this. It could carry up to 4000 watt hours of battery. Each bag on the bike could carry 48v 20 ah. Finished cargo mixte..jpg

Your budget is a bit out of range for your real desires. Battery alone for 48v 80 ah would be over 2 thou.

Here's the part where I tell people a 150 cc gas scooter would go a lot farther, a lot cheaper per mile, on a $1500 budget. I get it you like the bike. But in terms of cost per mile, nothing in my life comes close to being as cheap as small motorcycles I've owned, which get 75 mpg or more. Maybe you get one of those, and pedal the morning, then hop on the scooter after lunch. Cost per mile on my e bikes has always been about 20-30 cents a mile. Motorcycles, if bought used, and dirt cheap, more like 12 cents a mile.

However, I still say go for the e bike if you just like the idea. Just figure on it for a couple hours use mid day, giving you a break from pedaling so hard the entire day. Then you can get by on just one 48v 20 ah battery, which will take you 20-30 miles easily. You might then do what I was doing when I rode a long commute. Buy one new battery each year. Most of the time I had one nice new battery, one still very good one year old battery, and one old one that I could still get some good miles out of, but riding slower. But my budget only needed one battery per year.
 
dan has a point, 125-150cc 4-stroke scooters are the preferred courier mode of transportation over most of the planet for good reason.

For the ebike I'd suggest maybe first trying on the cheap with something that assists you during acceleration and recuperates energy with regen braking, since city traffic is so much stop and go this would take a lot of stress off your legs and cardio system.
A hub motor with a decent sized battery would do a good job with this.

Building a safe and reliable bike with huge range is possible, but quite expensive. Here's an example how it looks like
https://youtu.be/Z50cSlMdS2Y?t=200
 
I love regen, but I have the most use for it down hill. For quick stops on flat ground, it seems to me you'd have to dial up the regen force pretty high to get much value out of it, and just generally it doesn't seem worth it. Considering the trade off, which is that you'd need some power to the motor at all times to balance off core resistance.

What you need is a huge solar array canopy! In the winter you'd have to just put it all aside, but in the summer, all day power and shade too!
 
If you mean a 30-40' canopy over your charging station, great.

Not part of the bike while in use, be more of a hindrance than a help.

Sent from my Nexus 6 using Tapatalk

 
I agree swap and go would be ideal, but my old roommate worked gig/app bike deliveries and never stopped back home while working.
But there seemed to be plenty of dwell time waiting on pickups and deliveries to opportunistically charge.
 
john61ct said:
If you mean a 30-40' canopy over your charging station, great.

More like this:
recumbent-bike-winning-the-Sun-Trip-race-of-solar-bikes.jpg


Photovoltaic 405 W peak: Clean Fizz panels 2.35 m² 132 cells Sunpower C60
Solar charger: 2 Génasun 54.2 V 8 A.

It was years ago, maybe one could do better. I think in this picture, it's 2015 and he's completing a 7000km race in 25 days - average 175 miles/day if my arithmetic is right.
 
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