High torque set up needed

[Matt_ZH]

Hello,

I want to shorten my commute and therefore electrify my bicycle. My commute includes bringing my child (two kids in a year) to the childcare. To do so i need to get up a steep incline with 15%. Height difference is 50m. The rest of the commute will be without trailer and includes another 200m up.
Besides for commutes i want to use it with the trailer for the kids. To avoid traffic it is always necessary to use roads with steep inclines.
I have a Raleigh Rochester trekking bike with 28" wheels and i am consider to use it for a conversion. I read a lot about pedelecs and possibilities of conversion but for my application i haven't found the solution. I would prefer a direct drive rear hub motor but its hard to find exact data. Also there are little information about the controller. A good controller could get me more torque out of the same motor at relative low speed.

The problem are:
1: A high load 170kg up a steep gradient 15%
2: In Switzerland we can use a motor with 500w power and 25 km/h max as a pedelec whereas in EU there are only 500W allowed. Most conversion kits i saw are for th E U market with only 250W units. For my incline i would need a bit more than 500W but thats for a short time thus not continuous power.
3 Speed should be legal that means under 30km/h

Must have is:
Strong climbing
more than 500Wh Battery
low maintenance

Nice to have is:
Regenerative braking
some cool user interface
good looking

Thanks for any information

edit weight is only 170kg instead of 270kg

[newb]

Welcome Matt,

Wow, 270kg - that's a lot. I think it would be a good idea to go with a geared motor vs a direct drive. Regen actually does very little in the way of recapturing energy, only real benefit would be the additional braking you get will when engaging the regen. If you go with a geared motor you will get alot more torque out of it at lower V's & A's and it's lighter and smaller (more discreet) plus, it freewheels (no resistance when you wish to ride it w/o power).

I would suggest you contact ES member "cell_man" about a 10 turn or even a 12 turn rear motor as I personally wouldn't want that much torque pulling on my forks.

He has motors with newer composite gears which are much better at handling the stress being applied with that weight up such a steep hill. He can provide everything you require and he does it at a reasonable price.

However, if you wish to purchase more locally the here are a few vendors to consider.

NL:
http://www.v-fiets.com/shop/Conversion-sets-c-3.html

http://www.fietsunie.nl/

DE:
http://www.ebike-solutions.de/epages/62 ... s/62204758

AT:
http://elfkw.at/shopen


Good Luck


added: if you decide to go w/ direct drive motor then I would suggest you contact ES member "Methods" as he has a selection of high torque direct drive motors.

[Matt_ZH]

Sorry that 270kg was a typo its 170kg (100kg for me + 20 for the bike + 30 for the trailer)which is still a lot.

I primary want to use regenerative braking to safe on the friction brakes. It would be even ok if the energy is dissipated via a brake resistor. A geared motor would be an option if the gears are really tough.

[Chalo]

This sounds like a job for Stokemonkey!

[nechaus]

my thoughts for shopping list

Direct Drive motor
Controller
Lifep04 batteries like ping or cell man, OR you can go any buy lipos
run it at 60 or 72 volts
High torque like 8x8 9c wind, magic pie, Ht series crystalyte


you may need more battery watt hour

[MadRhino]

This sounds like a job for Stokemonkey!

+1

Torque and stability, to pull the kids.

[Should be working]

Pls explain the benefits of a geared motor vs. direct-drive--I realize that a lot of this was said over on 'my' thread but I'm still learning. I think I understand that direct-drive doesn't 'amplify' the motor's energy to the wheels as much as a geared motor would, which is why the geared motor provides more torque? So why would anyone want direct-drive at all? I think the answers are cost and regen--is it not the case that geared motors can't have regen, but direct-drive can?

And do the terms 'geared motor' and 'direct-drive' motor both apply only to hub motors? The inline motors (like Ecospeed?) are midline motors, not hubs, and they are by definition 'geared'--but not with their own gears, instead with the gears of the bike?

Thanks in advance for the helpful teaching going on here.

[MadRhino]

Geared motors are usually geared down 5 to 1, meaning the motor spins 5 turns to make the wheel do a turn. This gives more torque, but those motors have a set of gears and a clutch inside, keeping them from having good heat dissipation. So those motors have more torque at low power levels, but can't be fed as much power as a direct drive hub motor. The result is that, with high power level, a DD hub has the potential for much more torque.

When we are talking about a stokemonkey, this means that a hub motor is used outside of the wheel and drives a chain through a gear reduction. A DD hub used that way, has the advantages of both a geared hub and a DD, plus a range of gear selection. This makes for the best climbers, especially for those who don't want to rush up the hills at full speed, or have to pull extra weight.

[BikeFanatic]

Direct drive motors are capable of regen which is useful for braking, they can also can take and put out a lot of power. Methods sells high torque lower speed direct drive Hub motors. Hub motors are laced into a wheel. The bad news is direct drive motors are heavy and are difficult to pedal more than 15 MPH without power, say if the battery dies and you have to pedal home. I have a few hub motors and on 48 volts high torque ones will be very simple solution for you.

Geared hub motors freewheel, so they are easier to pedal but do not do regen. I never owned one so That's all I know about them.

[Should be working]

So those motors have more torque at low power levels, but can't be fed as much power as a direct drive hub motor. The result is that, with high power level, a DD hub has the potential for much more torque.

So this means that the geared motor can't receive as much power but produces more torque at low power than a DD hub motor by its gearing. And a DD hub motor can take more power and produce more torque that way, i.e. more power in, more torque out. So it seems like a wash when deciding between them? Which produces more torque NET at low speed (e.g. 5 mph up a steep hill)? Does this depend on the individual motor or is one type better at low speed/steep climb?

When we are talking about a stokemonkey, this means that a hub motor is used outside of the wheel and drives a chain through a gear reduction. A DD hub used that way, has the advantages of both a geared hub and a DD, plus a range of gear selection.

I thought a stokemonkey was a brand of motor, which seems to be at least temporarily defunct. How is it used outside the wheel? But if it's not available anyway I guess it doesn't matter. ebikes.ca suggests it is similar to ecospeed and eLation and Cyclone, but I know Cyclone has a poor reputation on this board.

[Ykick]

Should be working - Geared hub motor is similar to using low gear in a car. Engine spins fast but you can climb steep grades. While direct drive can be tweaked (feeding massive power, slow RPM, small wheel, etc.) to maximize hill climbing it's usually not as cost effective as a simple, robust geared hub motor.

The type that connects and runs through the bicycle gearing is usually very effective for hills but can be quite complicated and in some cases not very reliable.

I suggest you look for suitable demos in and around your area? I think some users held a gathering last year in the bay area? Perhaps check around for other events where you can at least witness what might have a chance of doing what you need to do?

[John in CR]

I'd suggest using this bicycle power calculator, especially if you want to limit your ebike to the legal power limit. http://www.kreuzotter.de/english/espeed.htm

With 170kg load, plus another 40kg of bike, I came up with 500W of motor output power plus 100W of leg power up a 16% grade will produce a speed of under 7kph up those hills. Without an oddly small wheel no hubmotors are going to do that, so I agree with the posters suggesting a hubmotor used as a mid-drive and run through the bike's gears.

[Matt_ZH]

Thanks for the replies.

Actually i am quite reluctant to use the chain drive for the motor assist. I have torn some chains just by my own weight and force. I just worry the bicycle drive train is not able to endure the increased power by the motor assist I also read stories of people which have to change chains monthly this is a no go for me.


As for Voltage and Current to my knowledge and i am electrical engineer if i want higher torque i need more current higher voltage would mean higher speeds. Ideally there would be some kind of VVVF (variable voltage variable frequency )controller but the bike controllers are much simpler. So going with 36V and more than 30 A should do the trick.

For hill climbing i will need more than 500W of assist. this is OK as its for only a short time and nor the continuous output. If the set up can deliver 1kW at the wheel for a limited time of 3 minutes all my worries are gone. The police will not care if am going up hill with 10km/h instead of 5 km/h.

For geared vs direct drive it is true that a 5:1 gear can deliver more torque. But thats only if both motors have the same number of poles and windings. If the direct drive has five times the poles it will be able to deliver the same torque at the same speed. In my case i would need a motor which delivers 1kW at a speed of 8-12km/h with 28" wheels. I am aware that i will end with an overpowered set up which i have to limit in the controller. But that is what the ready to drive pedelecs do.

[o00scorpion00o]

I personally wouldn't be worried about European electric Bicycle laws, they are only as good as local law enforcement.

Here in Ireland there is no such legislation to enforce such ridiculous laws. The E.U has many stupid laws, for instance high powered hid car headlight kits are retro fitted to cars which is completely illegal yet they are an increasingly common sight and blinding many drivers which I think should be more of a priority than limiting Electric bikers to such stupidly low levels!!!

If you need 2000 watts to make your journey comfortably and at a level that you won't be bogging down your motor, then do it!

I would say an 8T or 10T motor from emissions-free would do the job very nicely. But If pulling power is what you need and pulling heavy loads up a hill is probably much better to go with a 24-26 inch rear wheel, 20" would be much better again if you can find a bike capable of such a small wheel.

Smaller wheels are much easier on the motor but will give you a slower top speed so you will need more voltage. You would loose about 5 mph going from 26" wheel to 20" but you have a lot more torque.

Have a chat will cell-man. from emissions free.com. it can take him a few days to reply as he is really busy.

You have a battery to choose too, how far do you need to go and how fast ? A battery capable of good discharge rates for climbing and decent range will be expensive, there is no getting away from that!

But if it were me I would go with a slow wind motor in a small wheel and go with higher voltage, that means you will generate less heat than in a 26" wheel with less voltage and more current!

If you don't act the fool on the road and don't draw attention to yourself, you will have no problems with the law!

[dogman]

A tough nut to crack, given the extra cargo. 15% is a bear for most motors when run under 1000w. It simply isn't going to happen at 500w, even with through the chain motors.

1000w for sure,such as 48v 20 amps, or even more, 48v 30 amps. Your best bet, not through the gears, is going to be the lowest speed winding dd motor you can find, and quite possibly two motors. Maybe a second gearmotor on the front wheel, that gets used only on the hills, and a powerfull dd motor on the back. Good thing the hill is short, you can flog a motor badly if the duration is really that short.

[o00scorpion00o]

The Magic Pie is a really good torque wind motor and it's large diameter helps keep it cool. You need to find one that takes an external controller, or they have a new magic pie III which is a lot better, but you are still better using an external controller

But I think slow high torque geared hubs would be a lot more efficient than a torque wound direct drive motor for slow speeds ?

The direst drive motors would spin slower meaning less efficiency and heat.

20" wheels are the way to go I believe now for such set ups.

You will need a good battery and you need to tell us your range and speed expectations ?

[dogman]

Good point, 20" wheels for the win. Maybe a delta trike? Bmx bike? Then take a motor winding intended for 26", and create a slow speed 20" wheel with it.

What you need is not going to be cheap. It's beyond the normal hubmotor capability.

[John in CR]

Sorry guys, but a single speed hubbie can't put out max power at 7kph and also be capable of 25. Max power occurs at about half of no-load speed. Maybe the hills are short enough that a running start could make the climbs survivable for a fixed gear electric rig, but even a stop sign before a hill kills that idea, and I don't like recommending things that might work over something guaranteed to work.

[Matt_ZH]

I just wrote a email to emissions free for an offer. Their 1000W Mac rear kit with the 12T motors looks promising to me. I don't want to use 20" wheels so i rather chose a geared motor. Since the MAC has 16 poles as opposed to 8 of the competitor motors and 12 turn windings i expect a good torque from it. Their battery cells are also capable of delivering high currents.
Sure its going to cost me some bucks. But i will have a much better performance than from any stock pedelec. And cost even are lower than a high end pedelec from flyer or stromer which use propretiary technology. My father spend a fortune just to repair his flyer battery.

[pwbset]

Their 1000W Mac rear kit with the 12T motors looks promising to me.

Also interested in their 12T MAC. Let us know what they say. I'd like one of those and their 80A BMS on their 52v11.5ah triangular I think. Wondering if the 12T can handle 2.5kw for 18 minutes straight on an 80 degree day for my hill climb commute. Also wondering how fast it would be at 52v. LOL Hmm.

[newb]

Also interested in their 12T MAC. ...... Also wondering how fast it would be at 52v. LOL Hmm.

I have a 12t that i haven't laced yet but it has a no load spd of 18mph @ 38v, hopefully that should you some idea of what you can expect.

[pwbset]

I have a 12t that i haven't laced yet but it has a no load spd of 18mph @ 38v, hopefully that should you some idea of what you can expect.

Thanks for the info!

[o00scorpion00o]

I just wrote a email to emissions free for an offer. Their 1000W Mac rear kit with the 12T motors looks promising to me. I don't want to use 20" wheels so i rather chose a geared motor. Since the MAC has 16 poles as opposed to 8 of the competitor motors and 12 turn windings i expect a good torque from it. Their battery cells are also capable of delivering high currents.
Sure its going to cost me some bucks. But i will have a much better performance than from any stock pedelec. And cost even are lower than a high end pedelec from flyer or stromer which use propretiary technology. My father spend a fortune just to repair his flyer battery.

I think we have all started off with basic lower cost kits only to realise that we should have went for the better more expensive system to begin with. So the mac will be a great choice.

The 8T on 60 volts gives me 40 mph and super torque, so the 12T, while slower should pull like a train up a hill even pulling a heavy load!

I will give you some good advice, cell-man will be installing temperature sensors in some of the macs, maybe by request, so ask him if he can do it for you. It will be the best think you could ever to to make sure you don't cook your motor!!!

I hope he doesn't mind me saying that but it's just one of a few things he is doing to improve the mac!

And ask cell-man if you can hook it up to this

http://www.speedict.com/

Here is a thread discussing the divice which I think has great potential !

viewtopic.php?f=3&t=22919

The trusty old cycle analyst is being upgraded to include temperature sensing and would be well worth getting when it comes out. So just ask Cell-man which one his temperature sensor would be most compatible with !

The speedict kit comes with a temperature sensor, but you would have to open up the motor and stick it to the windings yourself, but I strongly recommend it if climing hills while pulling loads!

Buy you won't go far wrong with a mac and cell-man's batteries!

Best of luck and let us know how you get on when you put all together, I would be interested to know what you think of it!

[Lebowski]

I just wrote a email to emissions free for an offer. Their 1000W Mac rear kit with the 12T motors looks promising to me. I don't want to use 20" wheels so i rather chose a geared motor. Since the MAC has 16 poles as opposed to 8 of the competitor motors and 12 turn windings i expect a good torque from it. Their battery cells are also capable of delivering high currents.
Sure its going to cost me some bucks. But i will have a much better performance than from any stock pedelec. And cost even are lower than a high end pedelec from flyer or stromer which use propretiary technology. My father spend a fortune just to repair his flyer battery.

I'd be interested to hear what cellmans shipping costs to Switzerland are (I'm close to Zurich), please let me know !

[pwbset]

The 8T on 60 volts gives me 40 mph and super torque, so the 12T, while slower should pull like a train up a hill even pulling a heavy load!

I'm really leaning towards a 12T at this point... do you think it would be able to handle ~2kw for 15 minutes straight at 67v30A or am I just going to fry the clutch/gears? I could also run it at 52v40A, but am afraid that might be a bit slow. I climb a fairly serious hill, but want to go as light weight as possible. Thanks for your opinion!