Fat Man Commuter - 270lbs on 700c

After reading as much as I could sort through in a couple of weeks, I have come back with my build ideas and questions.

I am 270lbs
I enjoy regular hikes of aproximately 6kms daily.
I can easily pull of a 4 or 5 Km Hilly bike ride on my Hybrid Rocky Mountain Whistler 10 Bicycle.

I live exactly 10kms from work. From West Saint John, NB To East Side. The round trip commute is 20 Kms.
Often I have to work split shifts so my trip for the day become 40kms.
I can plug in at work for a recharge while I am working.

The terrain is mostly small hills with five, 1kms Hills aprox 5% grade along the way.
Thats my daily commute and I would like to be able to head out the back roads for a country drive occasionally.
I enjoy pedaling along small hills and flats but the big hills really kill me.

I have a budget now of about $1600
I prefer to do things right from the beginning and to put good money into parts that are important.
The throttle and wiring seems easy enough.
I believe I should run a
48v14-20AH Battery (I would like to have lots of reserve)
with a 40amp controller (giving me better performance hill climbing)

My dilemma is in choosing a motor. Remember my Bike has large 700c Rims (I bought it for easier rolling resistance while pedaling and I use a hybrid tire city center with the knobby edge)
I have decided on a brush-less Direct Drive. I want the best quality and most dependable for my application. I was thinking about the crystalyte X5 and the HS3540s or an HT3525 but the reviews have been showing the new HT/HS motors burning up. I am wondering if there are better motors out there and would an older more proven motor be better?

I don't mind spending extra for heat sensors if I must. I would prefer to just over build using quality equipment.
Thank you for your input, ahead of time

I'm hoping to use the bike everyday weather permitting. It would save me aprox $200-$300 per month in gasoline.
I could then use these funds to fund my next projects

Dave

I would go with 9c or an aotema motor. I never had a problem with those motors running a battery at 48 volts with a 30a controller

Well,the big battery will be diffucult to carry any way except in two sections in panniers. But if you went with typical 2c pouch cells you'd run into problems with too many amps for it if you run the 40 amp controller.

Furthermore, the way you fry a motor, is to choose the wrong winding, then ride it up too steep a hill with all the extra amps going straight to heat.

Fortunately, 5% grades is no problem for just about any motor. If you are in Canada, I'd recomend a 9 continent 2808 motor. Slightly better on hills, that is, better able to tolerate climbing the hills a tad slower with your weight. Run it on a bit less than 40 amps, in fact, since you are willing to pedal some, a 25 amp should be fine.

Battery? Cellman sells real nice A123 packs. If you really want range you could get a 20 ah. But I think the range you need is easily done by his 48v triangle pack. Those that have one are loving them.

A triangle pack to start with for the win, then if you really want more range, you can add something in paralell with it for the longer rides, like a 48v 10 ah pingbattery. All you need is the triangle pack for your daily rides, and a 5 amp charger to get recharged a bit on the quick side.

Do lots more reading about melting motors. Ive toasted a few, but it never put me off the 9c motor. You just have to realize what you are doing when you take a motor designed for 500-1000w, and feed it 4000w. A slowish winding will help get your weight up those hills, but 5% does not require the kind of super slow winding motors I like so much.

dsullivan said:

My dilemma is in choosing a motor. Remember my Bike has large 700c Rims (I bought it for easier rolling resistance while pedaling and I use a hybrid tire city center with the knobby edge)
I have decided on a brush-less Direct Drive. I want the best quality and most dependable for my application. I was thinking about the crystalyte X5 and the HS3540s or an HT3525 but the reviews have been showing the new HT/HS motors burning up. I am wondering if there are better motors out there and would an older more proven motor be better?

I don't mind spending extra for heat sensors if I must. I would prefer to just over build using quality equipment.
Thank you for your input, ahead of time

I'm hoping to use the bike everyday weather permitting. It would save me aprox $200-$300 per month in gasoline.
I could then use these funds to fund my next projects

Dave

Click to expand...

Hi Dave,

In my view you will need a nice torquey motor. So either a HT3525 or a 9C 2810 or something like that.

My experience is not extensive. However, I do have a Clyte HT3525, and I am very happy with it. I run it at 126V 45A, and it will overheat within 5 minutes on a 10% grade when inserting >3kW in it. However, I honestly believe you will not have to worry about a 48V 40A (2kW) setup on a 5% grade. Play around with the simulator from ebikes.ca. It is VERY accurate, and for the HT3525 the simulator gives this:

In other words, at those power levels (48V 40A) you can drive up a 5% hill, and it will overheat after 26 minutes.

My 9C 2810 is slightly smaller than my HT3525, so theoretically it will shed warmth slower than the Clyte. However, I do not have real world comparison data. I know Dogman is a fan of the 9C 2810 as well.

(EDIT) I just saw Dogman's response and recommendation for the 2808. Dogman, did you take into account the larger-than-average weight?

Whichever motor you choose, make sure to fixate it with 2 torque arms.

Yes, the weight is a big issue on the hills. But he's not proposing to ride up them with no pedaling, as in the simulator. I think the 2808 will be a slow enough winding for him to get up 5%. If he had longer hills of up to 7%, then I'd be calling for a slower winding.

To keep his speed up with the slow 2810 winding, he'd be needing to go to 72v, complicating the battery situation.

The HT motor should also be slow enough for his needs. Whatever motor, he needs to avoid falling into the trap of trying to feed it too many watts. 48v and 40 amps works great on the gentler grades, but put a lot of weight on one, and then head up steep hills and you end up making 1500 w into heat.

Again, the key thing is he's willing to do a bit more than faux pedaling. He should be able to get up those 5% grades easily by doing only some moderate pedaling that won't get him very sweaty. A sustainable 1200w won't fry his motor, if he's helping some on the pedals. It helps that the ride is fairly short, without one very long hill like my ride has.

Ah yes, the pedaling does make a difference. Reflects my own lazy attitude nowadays; I hardly pedal anymore....

Oh yeah, I have several bikes I pedal only off the start line, or when the hills are too steep to comfortably stand on.

Commuting, I find faux pedaling more comfy than sitting the saddle. Just a bit of real pedaling up the big hill home is all I did.

dsullivan said:

I'm hoping to use the bike everyday weather permitting. It would save me aprox $200-$300 per month in gasoline.
I could then use these funds to fund my next projects

Dave

Click to expand...

You may want to reconsider your projected savings

Projected saving 250
price / gal 4

gallons purchased 62.5
assumed mileage 25

miles travelable 1562.5

e-bike avg speed 17

projected travel time 91.91176471

Click to expand...

That's a lot of hours per week on an e-bike

I am not saying that you will not save money on fuel; but, that estimate is a bit high.

700C is making it hard to climb for motors and controllers. You'd have better torque and your system would run cooler with smaller diameter wheels.

Great first post Dave, and welcome to the electric revolution. Only a few of things. What kind of performance do you want and is it likely you'll want more, or would you stay golden at near pedal bike speeds? Will you still want to pedal 100% of the time? By performance I mean cruising speed as well as acceleration from both stops and passing. Second, I wanted to make sure you understand that with a DD hubmotor your days of riding that bike without using the motor are pretty much over due to the cogging drag of the motor if not in use. You'll definitely want to be sure to get hooked up with regen braking. With the extra speeds of electric assist brake maintenance gets to be a real pain for those of us pushing double the load of the little guys, and a nice light braking force from regen is nice and smooth, keeps the mechanicals fresh and cool for emergency stops on the downhills, and best of all (for me anyway) seldom changing pads or otherwise fiddling with brakes.

John

MadRhino said:

700C is making it hard to climb for motors and controllers. You'd have better torque and your system would run cooler with smaller diameter wheels.

Click to expand...

Yup.
And guess what? a 700c doesn't necessary have lower rolling resistance. This is a common misconception perpetuated by some of the most hardcore cyclists! rolling resistance is a function of tire friction, and hub drag, not the diameter of the wheel!

Just yesterday i had the 1.8" 26" 'city tire' wheels on my pedal bike inflated to about 50 PSI and i was blowing past the local lycra folks all day, LOL. I am a fairly strong pedaler, but here i was on a $80 wal mart mountain bike with tires that had lower rolling resistance than theirs.. and... win

What does 700c give you? slightly better gearing than a 26" wheel.. and the taller the tire, the better it rolls over 'inconsistencies' in the road. This is why the mountain bike world is going to '29ers'.

For hub motors, the smaller the wheel the better. Electric motors love high RPM and bicycle wheels don't move that fast. A 16" or 20" wheel will accelerate like a bat out of hell.

I can't recommend going with a mountain bike strongly enough.
For one, they can easily carry a ton of weight.
For two, they are built tough, and that is a plus for us fatsos ( i am about 240lbs )
For three, the best tires for high power are made for 26" wheels these days. Most hub motors come in a 26" wheel size.
For four, you will suddenly vie for suspension, disc brakes and fat tires the faster you go. It is a reality of going higher speeds. If you really get into this hobby, your build will eventually morph into a slow motorcycle.

BTW, the only reason HT/HS motors are burning up is because they have poor heat dissipation and people think that they can handle far higher power than they are actually capable of.

Run them at ~30 mph, select the right wind for the job, pedal along, and you'll never have problems.

Welcome to the addiction.

A 2808 will meet your needs. A 2810 may meet them a little better for climbing and off road trail riding, but the 2808 will be faster on the road and easier to pedal when the power is off.

48V 10AH is what you need for a battery. If you want more range, get two of them. A 25 to 30A controller would meet your needs as well. a 40 Amp would be fine, but limits your battery choices. Watch the C rate of the batteries you chose. The controller shouldn't exceet the max output of the batteries, or you'll damage them

A direct drive brushless motor suffers from something refered to as cogging, where the motor will cause some resistance when you try to pedal with the power off. The actual resistance is a small percent of your pedal force, and while noticable, is about equivilant to trying to ride with knobby tires on the street, or riding a roadbike tire 10lbs under inflated. I ride all of my bikes with hub DD motors, often without even carrying the battery. its never been a concern for me.

If it does cause you some concern, the cogging effect can be nearly completly eliminated by unplugging the motor from the controller when the motor won't be used.

I've read your comments and suggestions and used the ebike simulator and have come up with this.

I am now thinking
Cellman 52.5 Volt 11.5ah Triangle Battery
40 amp controller
Crystalyte HT3525

here is the comparison. It appears that on a long 5% grade the HT3525 will maintain roughly 30kms/hr and would take 23 minutes to overheat where the 9C5808 would overheat in roughly 12 minutes. Unfortunately it didn't have any slower options for the 9Cs.


I'm really looking for dependability and the triangle battery is just cool.
Any comments on using 52volts instead of a 48v system?

Also any other suggestions will be greatly valued.
When this is done I'll photo journal the build and my test results.

Thanks again
Dave

+1 for the Cellman battery.
What I see is that the HT3525 will give you slightly better acceleration and longer time-to-overheat at the cost of lower max speed, heavier motor, and more money. So it is more a matter of taste, your expectations, and what you are willing to spend.
Regarding the voltage; the higher the voltage, the faster you go.

If you go for a Clyte, I would recommend to buy a sensored version, aka with 3 hall sensors that talk to the controller. And for both 9C and Clyte motors you really would appreciate a controller that can be connected to a Cycle Analyst.

FWIW, cellmans battery is "48v" nominal. So it will work fine with 48v controllers. He just likes to use the voltage a 16s lifepo4 actually is.

Still think you don't really need 40 amps, but it will certainly be more fun to ride with 40. Your ride is short, and the hills mellow enough, I doubt you'll overheat the motor too much. Pedaling some on the hills will help the motor stay cooler, by climbing the hills a bit faster. Aim to keep your speed 15 mph up the hills or more. Should be no problem.

Maybe you already understand this, but you won't use 40 amps all of every ride. 25 mph on the flat will only take about 15 amps. 40 will only happen when on a steep hill.

Good choices, HT winding or 2808, either one will have that little bit of advantage on the hills, without sacrificing too much speed.

If you get a kit with a CA from Grin, you will have a DP Cycleananlyst, which will allow you to limit amps if you feel you are heating up that motor too much.

The 52 volt battery is essentualy a 48 volt battery. Cell Man just believes in a little more truth in advertising. But it has a 30A BMS, so a 40A controller will cause the BMS to go into overload.

The Clyte 3525 is $100 more than the 9C. Its also heavier.
The 9c can handle the 5% grade at full speed for 6km with no pedaling on a 40a controller. on a 30A it will do it even longer, but at lower speeds. Of course, the Clyte can do it for twice as long, but you will rarely find your self going up a 5% grade hill continusly for 6 straight km without pedaling.
A 2810 would do so even long.

All 3 are good choices. All 3 motors will exceed your needs.

Welcome to Endless Sphere.

You found the end of the internet. Most never get this far, but you reached it.

I wouldn't go anywhere else for E-bike advice. Nope. This is the headquarters, the central office, the peak of the mountain.

Good luck with your endeavor. Hey, you only barely mentioned your bike. What do you have? What kind of weight can it hold? That seems like a lot of weight for a bicycle. Is it heavy duty?

20km RT. Only 12.4 miles. That's under 20 minutes with my $600 total cost, including bike, 48v 1000W yescomusa kit (GM motor), including 18s battery pack and new controller capable of up to 100V pack.. If I kept the speed down to 20mph (~30kph) I could make 2 trips a day on one charge. Why on earth would you want to spend more than that?

excellent post thank you.
Regarding using sensored vs unsensored, all the reading says that the only big advantage to sensored are smoother take offs and many people are reporting fine take offs with sensorless. The comparison here http://endless-sphere.com/forums/viewtopic.php?f=3&t=15491 even suggests that the setup is easier and with less parts to go wrong, the sensorless should be even more reliable.

My question is what can you tell me from your experience that might change my current thoughts. Remember I have no experience so I am actually hanging on everyone's words.

Dogman thank you -"If you get a kit with a CA from Grin, you will have a DP Cycleananlyst, which will allow you to limit amps if you feel you are heating up that motor too much." -- I will definitely be using the DP Cycleanalyst. +2

Wesnewell - Could you explain more about your situation. How much do you and your rig weigh, how hilly is your trip and is it used as a daily commuter or just for fun? I am interested in seeing if your setup can help me modify my plans...

Thanks in advance guys. Really great info here. I am already doodling plans for welding a custom bike together for my next play rig

Dave

Sensorless require you to be moving forward for the motor to work. the latest Clyte are suppose to be able to start from bearly any turn of the wheel, but they still require forward movement.

However, a sensored can start like a car, or motorbike: Instantly. it can even start forward if you're rolling backwards. Its also smoother and more efficent, as the sensors tell the motor when to fire each phase, instead of just guessing like the sensorless do.

Install and setup for a sensored motor is harder. You have 1 extra plug to plug in. I know 1 extra plug is hard, right? Its a single 5 wire plug that runs along side the main phase wires from the motor to the controller. Nothing else is needed for setup.

To be fair, sensorless had their place. older motors were not as weather resistant, and water in the motor could damage the sensors. Newer motors are much better sealed, and don't often have this problem. The sensors could be replaced.

Sensored are just superior. Ride one and you'll understand. Plenty of people are happy with their sensorless motors, but I don't know of anyone who would trade their sensored hub for a sensorless.

I don't like sensorless, for I am in hills most of the time and that is where it bugs on a start, even tries to start backward sometimes. They also bug at high speed. Some don't care, mostly those who run low performance on the flat. I have 2 small 12 fet sensored-sensorless controllers that I keep on a shelf as backups, but most of my controllers are 18 fet sensored and upgraded for performance. A good controller and sensored motor are a must in the mountains.

If you are not after performance, the 12 fet sensored-sensorless can run both. If you buy a sensored motor, you will have the benefit of instant start, and can ride sensorless if you have a signal failure that you don't want to fix right now.

Thank you for the in depth explanation about sensors. I'm glad you include the one connector comment.

How about throttles? Do we have a preference?
My bike has a shimano quick fire trigger with triggers over and under. I'm wondering which type of throttle I should use? Ideas?

Dave

dsullivan said:

Thank you for the in depth explanation about sensors. I'm glad you include the one connector comment.

How about throttles? Do we have a preference?
My bike has a shimano quick fire trigger with triggers over and under. I'm wondering which type of throttle I should use? Ideas?

Dave

Click to expand...

Since you have trigger shifters then a half twist throttle should integrate nicely with them. I prefer the half twist to a full twist for a couple of reasons.

1. The full twists have been know to come apart with the grip sliding off the handlebar which leads to wide open throttle on the motor. It's pretty rare but can happen.

2. It's easier to hold a set speed over bumps with the half twist.

Gary