OP mentioned they want a top speed of 20mph, not the 43mph the motor is listed for, FYI.
San Francisco Cargo bike
- Thread starter mol3earth
- Start date
OP mentioned they want a top speed of 20mph, not the 43mph the motor is listed for, FYI.
ebike4healthandfitness
100 kW
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You'd really add another 10lbs of motor weight and spend 2x on the motor to optimize a couple % efficiency in an edge case condition?
I wouldn't. And i wouldn't recommend any sane person do that
The OP (in post #1) mentioned he or she weighed 175 lbs and the kids weigh 60 lbs (and growing) yet you only used a total vehicle weight of 220 lbs for the motor simulator. How much do you think that big tadpole cargo trike weighs? You need to add that to the rider weight of 235 lbs. Then we need to add in the weight of the hub motor, battery and controller. How much do you think that is going to weigh? The total will be a lot more than 220 lbs that is for certain! Now realizing how heavy this really is ask yourself how much of a penalty is 10 extra pounds going to be for 50% more (42mm vs. 28mm) stator width?
For this kind of massive load a wider stator would certainly not be a waste unless it was limited by the controller. Example: Phase runner holds a 42mm or 45mm stator motor back too much. Grin only recommends it to be used for motors in the 500 watt to 2000 watt range as it is limited to 40 battery amps. This with a max of 90 phase amps and 45 to 50 continuous phase amps without a heatsink.
P.S. I'm still waiting to hear back from leaf bike but I doubt a 42mm stator motor will be double the price of a RH212.
EDIT: Leaf got back to me with prices on the 42mm:
48V 52V 2000W front spoke hub motor - electric bike motor
This compared to the price of the RH212:
RH212 Standard Wind
Nine Continent Rear Cassette Motor, RH212 Model with Proper Bike Alignment, Statorade Ready, and L10 Connector. Standard (8.5 RPM/V) Winding Ideal for 24
ebikes.ca
$295 + $105 shipping vs. $260 + $28 shipping is not double the price. The leaf 42mm is only 38% more expensive.
Also notice the 42mm leaf only weighs 2.02 kg more (i.e. 8.6 kg vs. 6.58kg )than the RH212....not 10 pounds (i.e. 4.5+ kg) more.
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999zip999
100 TW
Just ⁷because your car can go 110 on the freeway doesn't mean you go 110 mph on the freeway. What do you think you have a throttle for do you always drive your car with your foot to the floor ? The 45 mm stator can deal with the hills a lot easier before overheating and melting. Remember he only wants to spend $1,000 you show me a package that can be completed and put on that bike for $1,000 that won't melt on the hills of San Francisco.
ebike4healthandfitness
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That motor 999zip999 listed has a speed range of 60 km/h to 75 km/h for a tire diameter range of 26" to 29" using the voltage range of 60v to 72v.
We haven't been using 60v to 72v though. We have been using 48v and the battery 999zip999 linked is also 48v. Furthermore the tire in question is 20" not 26" to 29". Therefore if we assume the low speed range of 60 km/h is for the 26" at 60v then a 20" at 48v works out to be 37 km/h which is only 23 mph.
So 999zip999's motor is not off by much.
999zip999
100 TW
Plus that battery was made for a robot with p42 30amp cells. So I would Guess inside is well buss inside. As with my robot Robi would get mad if I used genetic Chinese cells. Plus that controller has a slower ramp up to speed.
Don't get me wrong it's $350 shipped so it's an inexpensive kit if you know what I mean.
Or a 1,000 watt mid-drive ? How much is that ?
Remember the 1,000 USD limit ?
Don't get me wrong it's $350 shipped so it's an inexpensive kit if you know what I mean.
Or a 1,000 watt mid-drive ? How much is that ?
Remember the 1,000 USD limit ?
999zip999
100 TW
Plus what kind of rear brake system do you have there ?
Answer please.
Answer please.
ebike4healthandfitness
100 kW
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See post #23.
Rear brake is a roller brake on a Nexus 3 speed hub. (I found that from the link the OP gave in post #14).
Oh and the trike weighs 30 kg (66 lbs) according to the specs found in the same link. This without electric motor, battery, controller, etc.
P.S. That battery you linked did not have 30 amp cells. It had 45 amp cells.
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PaPaSteve
1 kW
The Bafang store on Amazon shows a 750 watt kit for $655 (small battery)
Taga comes with disc brakes on the front which is a good feature.
Probably no need for a rear disc upgrade.
With the short wheelbase and heavy loaded front axle that the trike design has, it probably will skid the rear tire easily on a steep downhill.
For a 3 speed or any IGH a shift sensor is a must Link to Luna sensor
A 20" rear wheel in naturally lower geared verse a larger wheel but if 20% hills are common for your travels it might be wise to purchase the smaller crank sprocket first then gear up later if the gearing is too low.
The only other thing we do with the Bafang is to reprogram the controller to have 100% throttle capability in all power levels.
This assures the ability for a quick start at any intersection.
The standard Bafang has a cadence sensor to add in power and sometimes it is too slow a response when trying to get started in busy traffic.
Taga comes with disc brakes on the front which is a good feature.
Probably no need for a rear disc upgrade.
With the short wheelbase and heavy loaded front axle that the trike design has, it probably will skid the rear tire easily on a steep downhill.
For a 3 speed or any IGH a shift sensor is a must Link to Luna sensor
A 20" rear wheel in naturally lower geared verse a larger wheel but if 20% hills are common for your travels it might be wise to purchase the smaller crank sprocket first then gear up later if the gearing is too low.
The only other thing we do with the Bafang is to reprogram the controller to have 100% throttle capability in all power levels.
This assures the ability for a quick start at any intersection.
The standard Bafang has a cadence sensor to add in power and sometimes it is too slow a response when trying to get started in busy traffic.
It looks like the maximum grade of the steep portion is 11.2%, but mostly below 10%., for about a mile and a half. You probably can use a hub with some cooling as an option. I knew a guy at work, about 22 years ago that used a hub motor cargo bike to commute with his kid between Diamond Heights and the Financial District, so basically the same route. They didn't have mid drive kits back then. He was ahead of the times and was building his own packs too. He was wiry though, but sounds like you're total weight may be higher. When I first saw your thread, I thought maybe you were talking about Nob Hill or something.
Kottbullar
10 mW
Guys:
I've been lurking on this thread - and just wanted to say: Good job. Great analysis. A bit of 'divergence', and some great advice for a user seeking out a good decision. Cannot say enough.
I've been lurking on this thread - and just wanted to say: Good job. Great analysis. A bit of 'divergence', and some great advice for a user seeking out a good decision. Cannot say enough.
Chalo
100 TW
Poison-fueled combustion vehicles operate most efficiently at a small fraction of their maximum RPM and power output. EVs make peak efficiency at about 80% of their max RPM with full throttle. That alone should tell you all you need to know about an "overgeared" electric motor. If you want to cruise at 20mph, use an electric motor and voltage that spins at around 25-27mph with the wheel in the air. If you do that, most of the motor's best performance and efficiency will be at speeds you actually use, rather than at high speeds you don't use.
The more overpowered your system is, the less it matters to get the RPM range just right, because using partial throttle is the same as using lower voltage. But with optimized EVs, "foot to the floor" is actually best.
What is the difference between running at full throttle with a system with a voltage, say 48V, with approximately 48V going to the motor, and running partial throttle on a higher voltage system, with 48V going to the motor?
Chalo
100 TW
Only the amount of gross power you're leaving on the table. If the amps are the same, then the power will be the same-- but more volts same amps means a bigger, heavier, more expensive system, or one with shorter range.
Which is a good thing, if you have it on tap to use it when you need it. The point is, just ride partial throttle when you want to be in the efficient range, and use more when you need to. I never ride around at full throttle.
PaPaSteve
1 kW
What I should have written :
The standard Bafang has two ways to control power
1) The cadence sensor adds in power based on the persons pedal speed but the system is sometimes too slow to respond when trying to get started in busy traffic.
2) A handlebar controlled throttle that overrides the cadence sensor.
Cadence sensor for steady cruising, throttle for startup help.
Tongsheng mid-drives use a torque sensor on the cranks so they may respond quicker on start up. ... haven't tried one to know.
The standard Bafang has two ways to control power
1) The cadence sensor adds in power based on the persons pedal speed but the system is sometimes too slow to respond when trying to get started in busy traffic.
2) A handlebar controlled throttle that overrides the cadence sensor.
Cadence sensor for steady cruising, throttle for startup help.
Tongsheng mid-drives use a torque sensor on the cranks so they may respond quicker on start up. ... haven't tried one to know.
chuyskywalker
10 kW
I was enamored of the Taga a while back -- ultimately it wasn't going to fit two bigger kids. Though, during my research I did come across some folks that retrofitted a BBSXX onto the Taga's -- but it requires some frame modification to have it fit on the bike. There's, if I recall, some kind of protrusion near the BB that gets in the way of mounting it.
999zip999
100 TW
Chuyskywalker that a great point as trying to get a mxus 3,000 in a MTB I found the nut to big to fit on the axle so couldn't use that bike. Because they put the rear derailleur too close to the rear axle.
Yeah you have to look at all the angles to see what will actually fit on your particular bike model.
Neptronex I like the debate especially before he buys.
Living in his area he should be able to find an e-bike shop that has both a 1500 watt DD motor and a shop that has a mid drive so he can try both. Why not try before you buy.
Yeah you have to look at all the angles to see what will actually fit on your particular bike model.
Neptronex I like the debate especially before he buys.
Living in his area he should be able to find an e-bike shop that has both a 1500 watt DD motor and a shop that has a mid drive so he can try both. Why not try before you buy.
ebike4healthandfitness
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1500w (i.e. 48v x 35amp) DD hub is not going to be enough for 330+ lbs up a 20% grade. This especially as he or she did say in the OP the kids were 60 lbs and growing and "I just want to get around with my kids and up these hills reliably and for a long time to come." Then he or she also needs to be prepared for the possibility of headwinds while carrying this heavy load up hills as well. The effect of wind, even by itself, can really take its toll on both legs and a motor.....and San Francisco is a very windy place!
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999zip999
100 TW
San Francisco I live south of San Francisco in Burlingame we go up into the city like hate Ashbury and go dancing.
There was this one bartender that like me for driving all the way up from Burlingame and always gave me free drinks even when I introduced my girlfriend to him he still gave me free drinks. Oh the I-beam that's what the place is called that was wild San Francisco is one wild place I remember I was told don't go to the tenderloin district.
That just made me more interested but I never did go to the tenderloin.
There was this one bartender that like me for driving all the way up from Burlingame and always gave me free drinks even when I introduced my girlfriend to him he still gave me free drinks. Oh the I-beam that's what the place is called that was wild San Francisco is one wild place I remember I was told don't go to the tenderloin district.
That just made me more interested but I never did go to the tenderloin.
999zip999
100 TW
48lv x 50amp is 2,600 amps with the BT BMS the motor should not melt.
Don't get me wrong if I was to have the mid drive I'd want to hdn at a thousand Watts.
Sorry the reason I'm biased is I have a cyc pro2 kit and after two years they sold me a working controller for $60 and $30 shipping a huge discount for their X6 controller because the 855 Bluetooth controller from ASI never worked does anybody want it they try to download it with their own software and not using ASI software and it never worked. But Cyc what is the knowledge that they had to fall with the controller they just kept telling me what to do for a year and a half never worked. They played me a fool anyway I got the 1,200 kid plus 2 years later a $90 controller to make it work. Does anyone want to take it off my hands maybe a trade you can ride it and make it work and try to program it at my house before you take it out of my bike they never went more than 15 miles.
Don't get me wrong if I was to have the mid drive I'd want to hdn at a thousand Watts.
Sorry the reason I'm biased is I have a cyc pro2 kit and after two years they sold me a working controller for $60 and $30 shipping a huge discount for their X6 controller because the 855 Bluetooth controller from ASI never worked does anybody want it they try to download it with their own software and not using ASI software and it never worked. But Cyc what is the knowledge that they had to fall with the controller they just kept telling me what to do for a year and a half never worked. They played me a fool anyway I got the 1,200 kid plus 2 years later a $90 controller to make it work. Does anyone want to take it off my hands maybe a trade you can ride it and make it work and try to program it at my house before you take it out of my bike they never went more than 15 miles.
999zip999
100 TW
Battery hookup only has so many of those batteries if you want a $99 battery that's overbuilt for your knees won't tell you how to put a BMS on it and we'll tell you what charge you to get.
But if you don't get that battery 48 volt now it won't be available tomorrow guaranteed
But if you don't get that battery 48 volt now it won't be available tomorrow guaranteed
Yeah, they won't be around for long if you keep talking about them. I bought one this morning, $99.99 plus $22 for shipping.
A new 14s5p 18ah battery made out of 2170 cells that are rated for 45a continuous for $122 seems like a good deal -- if you have the knowledge and skill to make it work.
mol3earth
1 mW
the bike doesnt have rim brake holders.
the bike only has a rear drum brake right now. i think i can find an adapter to make disc brakes work, but im not sure about rim brakes
that link is not working for me (sailmotor.com appears to be down)
999zip999
100 TW
Hell bells !!!
Thanks for the answer to the question because I was scratch my head I know other people told me I'm stupid on page three and page 10 page yeah but I'll tell you what pays a good girl I had to let her go today she was sad.
So because you limitations you have to get a med drive 1,000 w and that battery that I showed you by it now we will teach you how to put a BMS on it Bluetooth it'll cost another hundred bucks but there you go.
You know the battery is the heart of an electric bike system this battery can put out 150 amps great you only need it but out 35 amps wow do you think that battery is going to sweat your little load.
Yeah exactly I need some of those cells I might just buy one to get eight of those cells I hate the shipping cost though. Hell stop me stop me I don't need one I'm not going to buy to buy you almost tricked me. F*** you. Like I need more motors more controllers or more working batteries you guys tempted me.
Thanks for the answer to the question because I was scratch my head I know other people told me I'm stupid on page three and page 10 page yeah but I'll tell you what pays a good girl I had to let her go today she was sad.
So because you limitations you have to get a med drive 1,000 w and that battery that I showed you by it now we will teach you how to put a BMS on it Bluetooth it'll cost another hundred bucks but there you go.
You know the battery is the heart of an electric bike system this battery can put out 150 amps great you only need it but out 35 amps wow do you think that battery is going to sweat your little load.
Yeah exactly I need some of those cells I might just buy one to get eight of those cells I hate the shipping cost though. Hell stop me stop me I don't need one I'm not going to buy to buy you almost tricked me. F*** you. Like I need more motors more controllers or more working batteries you guys tempted me.
999zip999
100 TW
In your situation with the rear brakes a mid drive might be the easiest way out. If it can fit with the interference from the bottom bracket that I read about ?
