Motor suggestion for 10 km 7-8% grade
- Thread starter dyana_by
- Start date
The BMC or Mac geared motors should be fine, as long as you're using them well below rated power. For that climb, I wouldn't push the motor beyond 50-70% of rated power, and you really should have temperature monitoring on it.
You could also look at sealing up a direct drive motor and oil cooling it to help heat transfer.
The key is really going to be temperature monitoring, and it'll probably take some experimentation.
You could also look at sealing up a direct drive motor and oil cooling it to help heat transfer.
The key is really going to be temperature monitoring, and it'll probably take some experimentation.
MadRhino
100 GW
How fast do you want to climb it ? I presume that 8% average does mean that some sections could be much steeper.
I would go for a cromotor, but if you don't need the speed there might be some cheaper options. Small diameter wheels do climb better and cooler. That is one thing that you should consider, especially if you are riding on pavement.
In any case, if you buy a DD kit you will need a more powerful controller, So I gess you'd be better buying separately. Nothing is worse than a setup that slows down a lot when climbing, stalling is a killer.
I would go for a cromotor, but if you don't need the speed there might be some cheaper options. Small diameter wheels do climb better and cooler. That is one thing that you should consider, especially if you are riding on pavement.
In any case, if you buy a DD kit you will need a more powerful controller, So I gess you'd be better buying separately. Nothing is worse than a setup that slows down a lot when climbing, stalling is a killer.
bowlofsalad
100 kW
This question holds some exceptionally relative variables. What sort of legal(power capacity) and cost restraints do you have? What size is the rear wheel on the bicycle you intend to retrofit? What is the total weight(your body weight, battery, frame, luggage and so on) you are carrying? Do you plan to pedal some, a little, a lot, not at all? Do you already have a controller picked out? I am sure there is much more to consider, but I am the type that over thinks things.
The first stop I recommend is http://www.ebikes.ca/tools/simulator.html this tool, really fantastic. Chances are, with this tool and the right settings you'll have a pretty decent idea of some options available to you, maybe this tool alone will answer your questions.
Every situation is different, if you use a motor that could be borderline for thermal capacity and you just happen to have a strong headwind one day and more weight than expected you could end up destroying the hall sensors, ruining the magnets or some other bad events with the motor. The summary I am saying here is that unless you are within the motors limits at all times, I would probably say a temperature sensor isn't optional for these sorts of climbs. This may depend on the total weight and your willingness to pedal a lot though.
The first stop I recommend is http://www.ebikes.ca/tools/simulator.html this tool, really fantastic. Chances are, with this tool and the right settings you'll have a pretty decent idea of some options available to you, maybe this tool alone will answer your questions.
Every situation is different, if you use a motor that could be borderline for thermal capacity and you just happen to have a strong headwind one day and more weight than expected you could end up destroying the hall sensors, ruining the magnets or some other bad events with the motor. The summary I am saying here is that unless you are within the motors limits at all times, I would probably say a temperature sensor isn't optional for these sorts of climbs. This may depend on the total weight and your willingness to pedal a lot though.
wesnewell
100 GW
http://endless-sphere.com/forums/viewtopic.php?f=3&t=66302
A lot will depend on your weight when climbing hills.
A lot will depend on your weight when climbing hills.
Drunkskunk
100 GW
I think I remember that you had a Bafang 750w mid drive, and a 500w rear motor. which did you burn up on that hill? If it was the mid drive, there may be other reasons. If it was the rear drive, then you have a very serious hill indeed.
You need a slow wound wide motor. in most cases, a Slow wind 9C or MXUS would do it, But you might consider a Clyte HT3525 for a little more heat protection.
You need a slow wound wide motor. in most cases, a Slow wind 9C or MXUS would do it, But you might consider a Clyte HT3525 for a little more heat protection.
Here are some specs:
total weight (bike+battery+me) = 110kg
Pedal = medium/high
rear wheel= 26"
My battery = lion 18650 48v 32,76 ah
street type = off road (smooth, easy to pedal, no rocks)
speed = 8/10 kmh
temperature sensor = I have to buy one (mandatory this time)
Drunkskunk, I've burned the bafang 500w CST. Bafang 750w mid goes up in the same route without problems (for now)!
I'm thinking about a Clyte HT3525 because It's easy for me to buy in Europe.
Controller = I need suggestion
Thx.
Di
total weight (bike+battery+me) = 110kg
Pedal = medium/high
rear wheel= 26"
My battery = lion 18650 48v 32,76 ah
street type = off road (smooth, easy to pedal, no rocks)
speed = 8/10 kmh
temperature sensor = I have to buy one (mandatory this time)
Drunkskunk, I've burned the bafang 500w CST. Bafang 750w mid goes up in the same route without problems (for now)!
I'm thinking about a Clyte HT3525 because It's easy for me to buy in Europe.
Controller = I need suggestion
Thx.
Di
bowlofsalad
100 kW
dyana_by said:
Great. Adaptto mini-e or BAC800+(not released as of yet so far as I know) with a cycle analyst version 3(CAv3, really any controller with some soldered modifications can be used with a CAv3) seem like the options to go with. Automatic thermal rollback is what you want for the motor and these are devices that have this. In addition these controllers I suggest use field oriented control which add to overall motor efficiency (less heat) by around 3% and make a motor run considerably quieter compared to trapezoidal. Collectively these options are costly, but you might ask yourself, "how much does reliability matter to me?". I probably wouldn't consider doing without automatic thermal rollback.
That motor doesn't seem like a bad choice, though I don't know how it's going to perform if you actually plan to go up at 10kph, the simulator I linked to suggests it'll be perfectly fine albeit at less than ideal motor efficiency. A lot of people have said that geared hub motors have more torque when compared to direct drive, I found this so confusing for a long time. The reality is motor efficiency is tied to motor RPM. What they are actually saying is that geared hub motors have far better starting and slow speed efficiency. A geared hub motor means there is a reduction ratio that allows the motor to turn several times for every one revolution. So say your wheel is turning at 85rpm or so, with a reduction ratio 5:1, that means for every one turn of the wheel at 85rpm, the motor will turn 425 times(compared to a direct drive hub motor which spins at a 1:1 ratio, or in this hypothetical situation 85rpm), likely allowing the motor to be in a more ideal point in it's efficiency curve.
I imagine this is obvious, but it's worth repeating. Motor efficiency basically means an amount of energy that is either being turned into heat or propulsion. So if a motor is at 57% efficiency where a geared motor might be operating at 66% efficiency (relative to the RPM) temperature and power consumption differences can be considerable. I am not trying to say that the HT3525 is a bad choice, just sharing a perspective. A massive direct drive hub motor will probably stand long runs without much overheating or damage, or you could always vent a direct drive and it'll run plenty cool at pretty low speeds. To me, the potential advantages that might come with a geared hub motor are lower weight, smaller size and lower speed (acceleration and some hill climbing) efficiency. Of course, direct drive is far quieter and there are no gears to break or clutches to fail in direct drive hub motors. Pros and cons to weigh.
wesnewell
100 GW
The H3525 will never overheat up a 8% grade if you keep it between 8 and 25kph up the hill on 48V. I'd get a 48V 12 fet minimum controller. The MXUS 3000 would scoot up itat max speed without a problem and a lot steeper than 8% without a problem.
MadRhino
100 GW
Again, 10 Km 8% average doesn't tell how steep you have to climb. it can be mostly 4% with some sections that are very steep and that will make a nice 8% average, when it it is much harder than the average might seem.
I have a 10% average trail here that has a very steep section, that makes it necessary to build high power. No H motor ever survived it twice. Friends with mid drives break their chain or fry their motor in that trail. I do it fast with a cromotor, or the X 5404 when the trail conditions are too bad to speed.
Climbing does involve many factors, as Bowlofsalad pointed out. A long hill that you climb everyday reliably, can become a motor killer one morning that you have to face 40 Mph winds.
I have a 10% average trail here that has a very steep section, that makes it necessary to build high power. No H motor ever survived it twice. Friends with mid drives break their chain or fry their motor in that trail. I do it fast with a cromotor, or the X 5404 when the trail conditions are too bad to speed.
Climbing does involve many factors, as Bowlofsalad pointed out. A long hill that you climb everyday reliably, can become a motor killer one morning that you have to face 40 Mph winds.
I'm a little at a loss as to what you are trying to achieve or as to the exact configuration of your bike.dyana_by said:
It seems you have a massive 48V 32Ah battery (2C? What is BMS current limit?), a mid-drive that climbs the hill just fine, but had a CST that you smoked as a 'helper' motor.... Also - from earlier threads it seems you may want to use PAS - is that true?
It really only requires about 300W to climb a 10% grade with that weight at 10kph so the 750W mid-drive should not be working up a sweat. Why do you want another motor if you want to maintain the same slow speed? ('redundancy' is a good answer, particularly if this is a commuter).
It looks like the CST cooked because you had a mixed drive system and pumped a disproportionate amount of power into the CST for that speed and not enough into the mid-drive (which can do the climb alone). The CST was running very inefficiently at that speed and baked. On the face of it, your system should have worked if it was operated differently.
Please fill in some blanks here so your configuration, target speed, and rider/multi-motor operating modes are clearer...
I read your answers and are very interesting. I do not have all the basics
to understand perfectly, but it motivates me to learn.
There are 3 climbs, 200 meters each -10/12%, the remainder roughly 5 to 7%.
I could buy the H3525 if the toughest climbs are made by feet so there is
no risk of burning the engine?
I don't want a mid engine because I need on a downhill bike (the central engine take shots).
I have a question: If I give to a motor less power (Watt) than he needs, he become hot?
At the end with which motor (7,5kg max weight), controlller (and in case the battery, if mine is not suitable) do you recommend?
Thx!
Ps: In the pic the bike that needs a new motor.
to understand perfectly, but it motivates me to learn.
There are 3 climbs, 200 meters each -10/12%, the remainder roughly 5 to 7%.
I could buy the H3525 if the toughest climbs are made by feet so there is
no risk of burning the engine?
I don't want a mid engine because I need on a downhill bike (the central engine take shots).
I have a question: If I give to a motor less power (Watt) than he needs, he become hot?
At the end with which motor (7,5kg max weight), controlller (and in case the battery, if mine is not suitable) do you recommend?
Thx!
Ps: In the pic the bike that needs a new motor.
Attachments
dogman dan
1 PW
Any of the direct drive motors will do it, or the larger gear motors. But the more you weigh, the more you need the quicker self cooling of a direct drive, so you don't heat soak it during the climb. This applies only if you are relatively light, under 250 pounds for sure, So 100 kilos ok, 125 kilos no
The better DD motors will do that climb, with enough power, so they never heat soak. A larger dd motor ( wider magnets than 28mm) run on 2000w, such as 48v 40 amps, will scamper up that hill fast enough to never overheat. This will work even if you are well above 125 kilos weight.
Above 10%, even for the short bit, best to up the power as Mad Rhino commented. At least 2000w is nice. But the 500w geared motors are best kept under 1500w. But again, if you are not heavy, a larger geared motor can be run on 1500w, and get you up that hill reliably. When I ride dirt, I do a few hundred feet of 15-25% grade, with most of it 4-8%, and some occasional very short 15%. By the time I ride about 5 miles, I generally turn so the motor can cool off on the downhill. Total climb only about 1000' vertical, but lots of ups and downs.
If you slow to less than 10 mph under full power, then you need more watts for sure!!!! If this is for trails too difficult to ride that slow, then you have some problems. But since the steep bits are so short, it should still work as long as most of the trail can be run at 12-15 mph, where the hub motor in 26" wheel is still moderately efficient. It's very clear that 8-10 kph under full load is WAAAAY too slow for it to be efficient.
If the trail is too difficult to ride that fast, just too rocky or twisty, then it's mid drive trail. Or, a smaller rear wheel can help a LOT. But if you are slow because it's all the motor can do, then you need a lot more motor for sure. One able to haul your 175 kilos, or whatever total bike weight with rider is, at more like 20 kph. Slower is fine for the short steep bits, but you can't crawl up the whole hill.
The better DD motors will do that climb, with enough power, so they never heat soak. A larger dd motor ( wider magnets than 28mm) run on 2000w, such as 48v 40 amps, will scamper up that hill fast enough to never overheat. This will work even if you are well above 125 kilos weight.
Above 10%, even for the short bit, best to up the power as Mad Rhino commented. At least 2000w is nice. But the 500w geared motors are best kept under 1500w. But again, if you are not heavy, a larger geared motor can be run on 1500w, and get you up that hill reliably. When I ride dirt, I do a few hundred feet of 15-25% grade, with most of it 4-8%, and some occasional very short 15%. By the time I ride about 5 miles, I generally turn so the motor can cool off on the downhill. Total climb only about 1000' vertical, but lots of ups and downs.
If you slow to less than 10 mph under full power, then you need more watts for sure!!!! If this is for trails too difficult to ride that slow, then you have some problems. But since the steep bits are so short, it should still work as long as most of the trail can be run at 12-15 mph, where the hub motor in 26" wheel is still moderately efficient. It's very clear that 8-10 kph under full load is WAAAAY too slow for it to be efficient.
If the trail is too difficult to ride that fast, just too rocky or twisty, then it's mid drive trail. Or, a smaller rear wheel can help a LOT. But if you are slow because it's all the motor can do, then you need a lot more motor for sure. One able to haul your 175 kilos, or whatever total bike weight with rider is, at more like 20 kph. Slower is fine for the short steep bits, but you can't crawl up the whole hill.
bowlofsalad
100 kW
dyana_by said:
I think what you are saying is you'd want to try and walk the e-bike up the hill in sections. This may or may not help. You'll probably need to spend some time pondering this notion, it's an important one to grasp and worth repeating. Motor efficiency is tied to it's RPM.
So when you are accelerating from a dead stop the motor efficiency from that stop is going to be very low and remain pretty low for a while depending on lots of things, especially when accelerating from a stop on a hill. In other words, you might be putting yourself into a worse situation by stopping and trying to walk it up certain sections, it's hard to know how it'll all work out though unless you try and pay close attention to the motors temperature. The best strategy is probably to go as fast as possible up the hill and not stop until at least a bit after the peak.
dyana_by said:
This idea could help or hurt depending on many things. The big killer here is stalling or just going up really really slow for a long time. No matter what, you probably want to consider venting a direct drive hub motor if that is the route you choose. The reason why so many might say to go with a mid drive for hill climbing relates to being able to easily keep the motor in an ideal spot in it's efficiency curve, you can climb really slowly with lowish power but still convert most of that power into propulsion rather than heat using a mid drive.
dyana_by said:
A slow wind, vented, high capacity direct drive hub motor might suit your needs. I am no direct drive hub motor guru, but an HT3525 might be a good way to go.
As to the controller, I suppose that really depends on your budget, wants and needs. Your best bet is probably an adaptto mini-e, field oriented control means higher motor efficiency, this means less heat as you climb, this setup also does automatic thermal cutoff. You don't absolutely have to use automatic thermal cutoff, so long as you are smart enough to keep an eye on a display that shows internal motor temperature and know when to let off the throttle. What this means is from there you could use basically any controller that will work with your motor, I'd personally go with the automatic cutoff but to each their own. You can add a cycle analyst version 3 (which has automatic thermal cut off) to any controller assuming you know how to solder.
Going into which battery is really pretty far off subject and a topic onto it's own.
Now I have a better idea. Then I'll take the HT 3525.
I saw these controllers:
http://shop.crystalyte-europe.com/product.php?productid=16529
http://shop.crystalyte-europe.com/product.php?productid=16464&cat=296&page=1
http://em3ev.com/store/index.php?route=product/product&path=38&product_id=83
http://em3ev.com/store/index.php?route=product/product&path=38&product_id=135
what do you think?
Do you have some other ideas about what controller could I buy ( Adaptto mini-e is too expensive)?
Is the S-LCD3 LCD Meter good or Cycle Analyst V3 is better?
This will be my shopping list:
Crystalyte HT3235
Cycle Analyst V3
Pas
Controller
temperature sensor
Throttle
Thx!
I saw these controllers:
http://shop.crystalyte-europe.com/product.php?productid=16529
http://shop.crystalyte-europe.com/product.php?productid=16464&cat=296&page=1
http://em3ev.com/store/index.php?route=product/product&path=38&product_id=83
http://em3ev.com/store/index.php?route=product/product&path=38&product_id=135
what do you think?
Do you have some other ideas about what controller could I buy ( Adaptto mini-e is too expensive)?
Is the S-LCD3 LCD Meter good or Cycle Analyst V3 is better?
This will be my shopping list:
Crystalyte HT3235
Cycle Analyst V3
Pas
Controller
temperature sensor
Throttle
Thx!
gensem
100 kW
magic pie 2 (cheap and can take multigear freewheel)
no temperature sensor (not really needed)
18fet 4110 infineon (cheap)
cycle analyst v3
thun (real pas)
cheap recipe for 3kw trouble free
no temperature sensor (not really needed)
18fet 4110 infineon (cheap)
cycle analyst v3
thun (real pas)
cheap recipe for 3kw trouble free
dogman dan
1 PW
Seriously folks, unless he is going up rough trails too difficult to ride above 10 mph, he can do this on any 48v hubmotor kit.
Even the cheap ones. A few hundred meters of steeper than 7% is fine, he just needs to pedal hard for those bits. The rest will go easy. I've done rides that were 10 miles long, never less than 8%, with the last mile 10%. Up it fine, on a 36v 800w direct drive motor kit.
If he will be riding serious trails, up the rock staircases that are hard to do at 15 mph, then he'll need slower winds, fancy controllers, or ideally a mid drive. But that will be only needed if the climbs are longer. 200m is not long enough to smoke a motor, if he pedals hard for that bit.
Pie a good suggestion, it's known to do well on the steeps. So is the HT. In Europe, he should be able to find a vendor of 9 continent type motors that are slow wind. Here in the USA, there is one vendor of a 6x9 wind 48v kit.
I would say with the motor he's chosen, a 48v 30 amps controller would be plenty. 40 amps nicer, but that means a stronger battery would be needed.
48v 40 amps controller that plugs into the CA, then he can set amps whatever he wants.
http://www.ebikes.ca/shop/conversion-kits/direct-drive/crystalyte-rear-hs-kit-advanced-pas.html
Even the cheap ones. A few hundred meters of steeper than 7% is fine, he just needs to pedal hard for those bits. The rest will go easy. I've done rides that were 10 miles long, never less than 8%, with the last mile 10%. Up it fine, on a 36v 800w direct drive motor kit.
If he will be riding serious trails, up the rock staircases that are hard to do at 15 mph, then he'll need slower winds, fancy controllers, or ideally a mid drive. But that will be only needed if the climbs are longer. 200m is not long enough to smoke a motor, if he pedals hard for that bit.
Pie a good suggestion, it's known to do well on the steeps. So is the HT. In Europe, he should be able to find a vendor of 9 continent type motors that are slow wind. Here in the USA, there is one vendor of a 6x9 wind 48v kit.
I would say with the motor he's chosen, a 48v 30 amps controller would be plenty. 40 amps nicer, but that means a stronger battery would be needed.
48v 40 amps controller that plugs into the CA, then he can set amps whatever he wants.
http://www.ebikes.ca/shop/conversion-kits/direct-drive/crystalyte-rear-hs-kit-advanced-pas.html
knutselmaaster
1 kW
I am trying out a XiongDa two speed engine, and in the low speed it will get you up easily at that speed.
On 36v 8A it took me up the steepest climb I could find locally (I got 60km/h going down, really steep) without pedaling at about 8km/h.
(rider+bike about 85kg)
On 36v 8A it took me up the steepest climb I could find locally (I got 60km/h going down, really steep) without pedaling at about 8km/h.
(rider+bike about 85kg)
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